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Plumbing & Heating

UFH Controller Upgrade

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Updated 21 October 2024

UFH Mat Damage Alarm Blog Link

Ketotek KTF0155A

20 October 2024 updated my under floor heating (UFH) controller from the existing BH-002 to Tuya compatible Ketotek KTF0155A.

Ketotek KTF0115 Thermostat InstructionsDownload

The reason for the update was to enable integration via the Tuya App with Home Assistant which will allow me to control the UFH when Octopus have periods of free energy.

Many thanks to ‘Speak to the Geek’ on YouTube for his video on this controller and how to create the Octopus Automation.

The replacement controller is the same dimensions and current switching capacity as the existing one and fits within the 35mm deep backbox, also I reused the existing floor buried temperature sensor which worked perfectly.

May 2019

I installed 150W/M electric underfloor heating in the kitchen and utility, each area was controlled using a separate TS700 programmable touch screen controller, these were bought off eBay for £20 each.

ts700
TS700 UFH Controller

TS700-Thermostat-instructions

The TS700 worked fine but wasn’t very user friendly to programme and so you ended up not making any changes after the initial setup.

Looking for an alernative controller which will be within my buget and fit the same footprint as the TS700 and be Smart, I came across the BHT-002 series of WiFi enabled Thermostats on Aliexpress.com.

The Smart aspect means I can use an App (Beca Smart) to control and programme the controller, also as its App based, I can share permissions with familiy so they also can control the floor heating, another bonus is the ability to have control via Alexa.

Moes
BHT-002-GBLW UFH Controller

BHT-002 Series Instructions

The BHT-002 Series of controller has different versions, the one I selected was 240v AC and capable of switching 16A, it has a backlit display and WiFi connectivity.

Connection to the iPhone App was painless and the instructions an setup are considerably easier than the TS700, the cost from Aliexpress was £20 each, unfortunatly I had to pay £11.07 Customs Duty when they came into the UK, but they were a breeze to swop over from the TS700 and work perfectly.

A nice touch is the comfort light on the controller to show it is powered, all in all, a really good move to make the change.

Plumbing & Heating

Spirovent RV2 Installation

2 Comments

The bedroom over the garage was always colder than the rest of the bedrooms, I decided to remove the existing single radiator and replace it with a Stelrad Compact K2 double radiator, this will give a heat output of 1645 Watts against the original radiators 907 Watts.

As the heating system needed to be drained down to enable me to make pipework modifications, I thought this would be a good time to add an air separator into the system.

My system already has two Automatic Air Vents, the difference with an air separator is that the heated water passes through a ‘packing’ which creates a turbulent water flow, any entrained air or micro bubbles are liberated, rising to the top of the device and vented.

The unit was very easy to install, the instructions contained a cutting gauge and the fitting location was ideal.

spiro out

I had just enough room to install the Spirovent RV2 on the bottom pipe which is the flow from the boiler, the manufactures instructions suggest that the unit should be installed at the point where the heated exit water is the hottest, so this was ideal.

After the radiator was replaced and the Spirovent RV2 installed, I slowly used my filling loop via a pressure regulator to refill the system, checking for leaks and venting the system until all are had been removed and the pressure stabilised at 1.5 bar.

After the system had been running for a few days and all the air had been vented, I used the Magnaclean Pro 2 as a dosing pot, and replenished the Fernox F1, again after a few days I used the Fernox test kit to confirm that the inhibitors concentration was satisfactory.

On Youtube one of the respected UK plumbing engineer asserted that the circulating heating water should be treated more like a heat transfer medium and more effort should be paid to its treatment, going so far as to say that the customer shouldn’t top the system up with the filling loop, introducing aerated water. He has a point, but in reality this will never happen.

SpiroVent RV2 ManualDownload
Spirotech_892366_TechnicalDownload
Plumbing & Heating

Installing Boiler Condensate Runoff

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Updated 14 November 2024

Table Of Contents
show

Overview

I currently have a Vaillant Thermocompact 624 System boiler which was installed in 2002 and some of the parts are now obsolete, so its only a matter of time before it needs replacement.

All new boilers now have to reach an ERP (Energy Related Product) minimum efficiency of 92.5% and only condensing boilers can achieve this, it does this by recovering the latent heat within the exhaust flue gases, this causes the water component of the flue gasses to condense and require disposal.

The boiler condensate produced varies in quantity and is acidic, therefore, only plastic parts can be used within the drain system (no copper or cast iron pipes unless the condensate has been neutralized first).

My existing boiler has no need for a condensate drain, however, when this packs in, any new boiler will.

I have read that if the condensate drains runs outside into a gully or soak-away, that the external pipe unless lagged or trace heated can freeze in the winter, and if the condensate can’t run away freely, the boiler will lockout until the pipe is thawed out.

Installation

So, that’s the backstory, fortunately for me, the boiler is in the garage and also a portion of a 11/2″ (40mm) drain pipe runs inside the garage, before going through the wall to connect into the soil stack, the drain pipe carries the waste water from the washing machine, dishwasher and utility sink.

darin pipe

The pipe used was 22.5mm plastic overflow pipe from the boiler to the drain pipe clamp, the picture below shows the capped boiler condensate pipe in advance of the installation.

capped condensate

Fitting this pipe without taking the garage apart was a ‘challenge’ and took ages!

wide angle

This pipe runs behind dado trunking where I used plastic cement to fix a 90 degree bend and ‘Tee’ with a capped stub so I can flush through if needed.

In this picture you can also see an earth clamp, this is fitted to the 15mm copper gas pipe  and is the main bonding conductor for the gas, unfortunatly it does not comply to BS7671 Electrical Regulations,  in so much as it is futher than 600mm from the point of entry and it is also installed after a branch, so I took the oppertunity to install a new clamp and 16mm2 main bonding conductor directly from the meters outgoing gas pipe to the consumer units earth bar, I could have used 10mm2 as I have a PME supply, but as I had the wire already, I made use of that.

tee

After doing the first drain I rechecked the pipe layout on a Vaillant EcoTech and it showed the condensate oulet on the other side of the boiler, so it was out with the drill again and fit another drain.

two pipe

This is the new gas main bonding conductor clamp fitted with the cable sealed after being routed of the enclosure, note the quality pipe soldering done by the British Gas Smartmeter man……Nice!

bonding

The additional uncapped drain below was a lot easier to fit as I removed the boilers isolator and frost stat to make more room.

left side

The drain has to have a fall of 43mm per meter, the pipe was taken to a 90 degree bend and then on to the drain pipe, the pipe is supported every 300mm.

trap

The  picture  shows a 75mm deep trap in the 22.5mm pipe, this then goes on to a McAlpine CONVALVE R28-NRV, this Non Return Valve will allow the flow from the boiler, but will restrict any back-flow from the drain pipe.

Installation of the NRV was very simple, I had to chisel the breeze block slightly so the clamp could fit without touching the wall, then drill a 15mm hole in the drain, debur the hole and fasten the 4 clamp screws and that’s it.

As the main drain pipe was at an angle and the condensate pipe came in vertically (the NRV will only work in this position), warming a small length of pipe and with an internal bending spring, I put a slight bend in the pipe, this was then cut to length and fitted between the pipe clamp and the NRV.

Once fully installed and all joints cemented, I ran a full bore water hose to check for leaks, once everything was checked, the exposed pipes were boxed in to stop any accidental damage (this pipe does form part of the boilers flue system when connected) and the garage was put back together again.

Not sure when my boiler will fail, but at least I’ve saved the plumber some time and effort and therefore I’ve saved some money in the long run.

Update

April 2023, Ideal Vouge Max 18kW system boiler ordered, checking on the guidance in Part L of the latest Building Regulations, there is now a requirement to insulate condensate pipes in unheated rooms, as my garage falls into this category, I have revised this blog.

Rip out and start again

12 April 23, Gas Safe engineer came to cap off the gas to enable me to remove and install a new boiler, he noted the existing condensate pipe size and as the boiler is located installed within an integral garage, this is classed as an unheated space and as such the condensate pipe will need upgrading to 32mm and protected against freezing by Class ‘0’ waterproof insulation.

So, time to start from scratch.

After removing the pipe lagging and McAlpine condensate pipe clamp, I was left with a new starting place.

The pipe above is 40mm solvent weld waster pipe, so I decided to insert a 40mm Tee with a 40mm to 32mm reducer for the condensate.

I had very little movement in the pipe as both ends were fixed, so I couldn’t simply cut the pipe and insert the Tee.

To get around the problem I filed the inner lip smooth of a 32mm coupling (socket), to make a slip coupling and cut the pipe, sliding the slip coupling onto the pipe, then fitting the Tee.

Solvent welding a stub of pipe in the Tee and then sliding the slip coupling back over the pipes to connect them after solvent welding.

All done ready for lagging.

Lagged with 32mm reducer installed ready for the 135o degree bends to take the pipe to the boiler with the correct fall.

32mm pipe was then installed up to the boiler and insulated with Condensate Pro lagging .

Once all the pipe was lagged it was time for a coffee and give my knees a rest!

New boiler all installed and fully compliant.

Plumbing & Heating

Central Heating Inhibitor Testing

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I recenly refilled my central heating system after completely draining down to install an automatic bypass valve and then a partial drain down to install a Magnaclean filter a bit later on, when the system was refilled I used Fernox F1 inhibitor (£18.99 per 500ml), as I didn’t know the volume of water in the system to meet the required minimum of 5% inhibitor per 100 litres of system water, and to be on the safe side, I used two bottles of Fernox, as you can not overdose the system, but this is wasteful and not to mention expensive.

In order to use the correct amount of inhibitor, I needed to find the volume of water and ‘spend to save’, so I bought a couple of inhibitor test kits, a Fernox Protector Test Kit for £23.46 and Sentinel x100 quick test for £4.99.

kits

So, why did I buy two test kits!

When the system was completely refilled I used Fernox F1, a few months later I decided to install the Magnaclean and needed some pipe fittings and inhibitor to top up the system resulting from the partial drain down, however, the merchant didn’t sell Fernox F1 only Sentinel x100, so I bought that.

Reading on a plumbing forum their was a suggestion that it was not a good idea to mix different manufactures inhibitor in the same system, I read this after I had already bought the x100 quick test kit off eBay.

I was refunded the cost of the x100 which was good of Plumb-It in Huntingdon, and bought Fernox F1 from another merchant and I also decided to buy as a long term investment a Fernox test kit.

As I now had two test kits, I thought I would see if the Sentinel x100 quick test would give an accurate indication of inhibitor strength of Fernox F1 as the x100 quick test kit will do two concentration tests for £4.99, rather than spend over £23, having said that, I can do 25 tests with the Fernox test kit, so it is cheaper overall, but as a DIY’r getting the x100 kit is more cost effective.

x100

Reading the hazard data sheets for x100 and Fernox, they contained the same chemicals and concentrations, Fernox F1 had one further component:

  • (Fernox & Sentinel) <2.5% Benzotriazole
  • (Fernox & Sentinel) 5% Sodium Molydate
  • (Fernox) Nitrilotriethanol

So I decided to test if the X100 kit would work in practice.

test1

Running some system water off using the vent on the Magnaclean, you fill the container to 1cm from the top and add two tablets, shake and then wait 10 minutes, the colour of the solution should then be compared with back of the x100 packet, if its the same yellow colour or deeper, its fine.

test2

Using the x100 test, the result appears my system water is of an adequate concentration.

The Fernox Inhibitor Test Kit was slightly more involved than the x100 test, but not difficult, the first thing to do was establish as baseline for your cold water which was used to fill the heating system with water.

f1

Filling the supplied container with 10ml of tap water, you add drops of the reagent and count the number of drops needed to change the solution from Blue to Orange.

blue
This is after one drop.
4 drops

To change my tap water from Blue to Orange took four (4) drops of reagent, shaking the bottle after each drop, this number will be subtracted from the drops total in the next part.

Washing out the container, I refilled this with central heating system water to 10ml as before.

f2
1 drop

One drop of reagent added.

9
Nine drops of reagent added.
nearly

Very nearly there.

39

After 39 drops, the solution changed to Orange, subtracting the baseline tap water 4 drops, means that 35 drops were needed overall, referring to the kit instruction, for Protector F1 at the recommended dose of 500ml for 100L of system water, a minimum of 9 drops of reagent is required to change from Blue to Orange, obviously, I’m well overdosed!!

This got me thinking of how I can determine how much water is in the heating system, the Fernox web site suggests that in a domestic system, volume can be estimated by counting the number of single panel radiators in a property and multiplying by ten. remembering to count double panel radiators as two single panels.

I have 13 radiators with 3 of these being doubles, therefore, using the formula above, this would be 16 x 10 = 160 Litres of System Water needing  just over 1.5 x 500ml bottles of Fernox F1.

To cross check this approximate value, I went the manufactures site for my radiators and found the data sheets, checking the sizes of my radiators against the Kw output of each one, this equaled a total of 10.87Kw, allowing that 1Kw requires 11 liters of water and adding a overhead of 25 litres for water in the boiler, indirect heating coil and system pipework, it worked out to 144.5 Litres of System Water needing just under 1.5 x 500ml bottles of Fernox F1.

The next time the system is completely drained I’ll use one 500ml bottle and then test to confirm if indeed it does need more than one bottle, once established I’ll sell the test kit on eBay.

Plumbing & Heating

Magnaclean Pro 2 Installation

6 Comments

Updated 19 April 2023

Note – Boiler replaced, however Magnaclean has been retained, Blog HERE.

MAGNA

Today (21 April 18), I decided to install a Magnaclean Pro 2 in my heating system which has a system boiler with hot water and central heating controlled using the ‘S’ plan design.

Magnaclean removes suspended solids (ferrous (Magnatite) and non ferrous) from the circulating water and traps them within the canister, this is then cleaned out at regular intervals.

The removal of these particulates will improve the longevity of the boiler and its parts, although my system water has been previously treated with inhibitor and ran clear during the drain down to fit this, these devices are installed when boilers are replaced in compliance with Building Regulations Part L , so I thought I’d bring it up to code.

The instructions specify that the Magnaclean is installed on the return to the boiler after the last radiator and before any system filling/pressurisation point, next to the boiler was a good location for me.

before

In order to make room for the Magnaclean to fit, the cold water filling loop needed to be raised.

drain

With the boiler power isolated, the case was removed to give more working room, a hoselok fitting was screwed onto the cold fill line and a hose ran to drain, I then isolated at the stopcock and drain the line ready for cutting the 15mm copper pipe and raising the whole assembly.

lifted

Cold fill raised and leak tested, the maximum height was governed by the length of the braided filling loop, the 22mm copper pipe nearest the boiler is the return and this has two marks 150mm apart indicating where the cuts need to be made.

I used the hoselok fitting on the return filling valve, and drained the heating system water opening a couple of upstairs radiators to break any vacuum.

pipe slice

Using a 22mm pipe slice it was fairly easy to cut the pipe, due to the restricted working space, I had to use pump pliers to grip and turn the pipe slice through some of its travel.

magnaclean base

The Magnaclean has a slip socket allowing the unit to slide over the pipe, then once engaged, the unit is lifted slightly so the inlet pipe engages allowing a nut and olive compression fitting to be made, I used jointing compound on both top and bottom olives before tightening.

The isolation valves are on the left, rather than the right, I had to use this orientation so I could easily access the isolation valves, I was going to use obtuse street elbows to form  a tight set in the return pipe, lifting the  Magnaclean clear of the flow pipe so I could operate the isolation valves, but this was way too much work for no real gain, especially as effective fluid flow is a function of the Magnaclean canister and not the valve orientation.

finished

Once the canister was pushed into place and the lid was tight, I closed the radiator vents and started to fill the system watching for leaks, the filling system pressure reducing valve is set for 1.5bar, so this was left open as I went round venting the upstairs radiators.

With the first round of venting done, I vented the Magnaclean and boilers circulation pump before turning the boiler on to heat.

This was followed by more venting until the majority of the air subsided, I isolated the Magnaclean and drained it so I could add 500ml of Fernox F1 inhibitor to the system, using the canister as a dosing pot.

As I only partially drained the system, (downstairs radiators are below the boiler so I only drained upstairs), 500ml should be sufficient to top up protection.

The installation went well with no leaks, and once the Magnaclean was proved to be ok, I registered the device online for the 10 year warranty.

I’ll post pictures in a few weeks of the Magnaclean magnet to see what it has picked up.

5 May 18 – Checked the Magnaclean and this is what it had caught:

magnatite

My Vaillant Thermocompact system was installed in 2003 and has 13 radiators piped in 10mm.  I’m very happy with the low level of magnetite retained and nothing was trapped within the lower filter housing, I’ll check this again in a years time, but so far so good 🙂

Plumbing & Heating

Central Heating Frost Protection

12 Comments

Updated 8 February 2023

Due to the recent cold snap and the fact that my central heating boiler is in the garage, I thought I’d install frost protection which will override the heating controls and fire up the boiler when the frost stat air temperature is  at or below +5℃, on the return pipework to the boiler is pipe stat set for +25℃ to turn the boiler off.

I have a Hive system which has a frost setting on the internal thermostat, this will bring the heating on if the temperature falls to +7℃ or below, the garage frost protection supplements this.

I spotted the Honeywell Frost Protection Kit – K42008628-001 comprising of a Frost Stat and Pipe Stat for £27.00 on eBay which is a really good price compared to Screwfix, Plumbase and Toolstation, so I bought it.

stat

For the installation, apart from the stats, I needed some heat resisting cable for the pipe stat and a double mounting box.

2 core and earth (3093Y) 0.75mm2 heat resisting white round flexible cable was bought off the internet from Under Control Instruments (www.undercontrol.co.uk)  for £4.00 which is temperature rated to 85℃.

The double gang surface box took a little bit of searching as I needed one with the flexibility to be used either vertically or horizontally with face-plates in the correct orientation, this cost £3.99 off eBay.

switch
Original installation showing the boilers isolating switch, the white flex is from the pipe stat.

First job was to wire the pipe stat and install it on the return pipe to the boiler, the stat is held in place with a spring which hook onto lugs on the base of the stat, getting the spring behind the pipe and stretching it to fit was made easier by tying a piece of string to one end of the spring and passing that behind the pipe.

Hooking the spring on the stat lug and keeping tension on the string, offer the stat to the pipe and pull the string to stretch the spring round the back of the pipe and hook it on the opposite lug, once done the string is simply cut off, this worked very easily once you got the knack.

pipe stat

With the power isolated, the existing isolator was opened and a picture taken for reference.

The Blue (Neutral (N)), Yellow (system calling for heat – switched 230v (L2)) and Red (Live (L1)) are from the junction box wiring centre, the opposing wires in the isolator are to the boiler.

isolator

Once everything was identified and proved dead, the wiring was removed and the new double gang surface box was fitted and wires pulled back in.

The two red sleeved blacks were separated, one will be connected back into L2, the other will be used by the frost protection system.

dual

The isolator was wired up and screwed into place, then the frost stat was fitted but it did not sit right as it was very slightly smaller than the back box so I needed packing to make it level, for this I used an off-cut of trunking lid, which did the trick.

packing

Once the Froststat was fixed in place and connected, the power was turned on and the frost protection tested by simulation that everything worked ok, including the operation of the Automatic Bypass Valve, once done the trigger temperature was set and the stat lid fixed in place.

I did notice a draft from behind my changeover switch on the left of the picture which was blowing across the face of the froststat, so I sealed the gap with decorators caulk to avoid inaccurate operation of the stat.

frost stat
Froststat and isolator, I bought additional lower cover screws and two were missing, the part number is Vaillant 290811 Clips.

As I have recently installed an Automatic Bypass Valve, I have not connected the frost stat to any motorised zone valves, therefore, once the air temperature is at or below +5℃,  a switched live will be applied to the boilers ‘calling for heat’ via the red sleeved black wire, the boiler will now fire and the circulation pump will operate.

As the motorised valves to either the central heating or hot water cylinder will be closed (‘S’ Plan system), the pumped water pressure will ‘lift’ the automatic bypass valve, maintaining a heated water flow to the boiler via the return pipework to which the pipe stat is affixed.

Once the return pipework is above +25℃, the pipe stat opens the series wired connection from the frost stat, this removes the switched live to the boiler, and the boiler enters ‘no heat run on mode’ before switching off.

The job took 2 hours and cost £35.00 and although we have never had a problem, the boiler and pipework in the garage should have had effective frost protection from day one.

Update

19 March 18 – The boiler came on unexpectedly and it was caused by the frost stat, closer inspection reveled that one of the bimetallic switch support pillar was snapped inside the unit, I’ve contacted the seller on eBay to see if I can get a replacement.

20 March 18 – eBay seller responded to my mail and is sending a replacement unit out.

24 March 18 – Replacement froststat arrived in good order and installed, all working now and the original unit sent back to the seller.

15 December 2022 – Had a few really cold days of around -5oC and the garage internal temperature sensor was reading 4.25oC

I took the cover off the frost stat and I must have moved the dial when I was replacing the lid as it was set below +5oC, I have readjusted this now, so all should be good.

3 February 2023 – Timeguard TRT031N electronic frost thermostat arrived from Fastlec at a cost of £22.36.

Manual for Timeguard

I found the mechanical frost stat to be quite inaccurate, the replacement is electronic and should therefore be reliable.

Plumbing & Heating

ESi Electronic Hot Water Cylinder Thermostat – ESCTDE/B – Part 1

21 Comments

UPDATED -27 April 2022

Table Of Contents
show

Background

In order to save energy and better regulate the temperature of my domestic hot water in my Santon Premier Plus unvented cylinder, I decided to install a ESCTDE/B Electronic Dual Cylinder Thermostat manufactured by ESI Controls, I bought online from PlumbNation.

box

Installation

The ESCTDE/B has two thermisters, one for the temperature reading and control, the other is for over-temperature trip and is set for 80℃, I must have a big problem if this operates as my boiler output temperature is set to 68℃.

thermistor

Fortunately the Santon Premier Plus has a spare dry thermostat pocket which the thermistors are a perfect fit.

pocket

I marked the location of the thermister pocket on the outside of the cylinder cover and offered up the ESCTDE/B back-plate and marked the centre hole.  I’m not sure what the ESCTDE/B is specifically designed to fit, but the rear fixing was perplexing and I didn’t want to modify the casing of the unit in case I invalidated the warranty.

back
Rear fixing arrangment

I used a cut down 20mm Female Adapter as a center bush, this was cut to size and fixed to the front cylinder cover.

bush
20mm Female Adapter
bush
Cut down female adapter used as a through cover fixing method.
bush
Fixing bush installed.
bush
Inside cover showing bush and thermostat pocket.

ESCTDE/B fixed to the bush with the three back-plate screws and as the female adapter has a serrated edge, it holds very well, the existing cylinder thermostat was turned up to position 5 which is 72℃, I have left this in circuit as another backup to over-temperature, as mentioned earlier, my boiler output temperature is set to 68℃, so only under a fault condition should this protection operate.

fixed
Indirect temperature setting and top view of fixing to ESCTDE/B.
Cover
Thermistors sliding into cylinder pocket.

Connections

NOTE – The mains supply to the ESCTBE/B MUST be from the same source as the heating systems programmer, this will ensure that there is only one point of electrical isolation for safe working.

I used 1mm 4 core and earth from the ESCTDE/B to the heating connection box, the ESCTDE/B does not have an earth connection, so this wire was parked, the unit requires a permanent 230v feed, the temperature calling relay changeover contacts are NOT volt free, although they are simply wired in series with the existing cylinder thermostat.

If the Legionella setting is active on the ESCTDE/B, the unit will automatically switch 230v to the Domestic Hot Water motorised valve (NOTE- this overrides any programmer settings), which in turn will bring on the heating, the output from the ESCTDE/B will remain on for 1 hour when the tank temperature is above 61℃.

As the bending radius of the connecting wires within the unit is quite tight, I used ferrules on the end of the wires, this ensures that no ‘whiskers’ can cause problems later.

wire
Ready for wire stripping.
wires
Insulation removed and conductors twisted.
wire
Bootlace ferrule pushed on.
wires
Bootlace crimped and job done.

Conclusion

Finished installation all working, as my hot water system is directly fed, (no header tank), I did not need to enable the ‘disinfection mode’, this mode increases the water temperature to 61℃ for 1 hour to kill Legionella, however, as the feature exists, I set it to activate once per week.

finished
We had been away for a few days hence the water temperature was showing 21℃, the unit was initially set for 48℃ and the Red LED shows the cylinder is calling for heat.
finished
Picture showing wiring from ESCTDE/B to heating terminal box and the tank temperature now reached the set-point of 48℃.

Problem

Apologies for not updating this blog and a recent comment made me revisit this, so thank you.

I have decide to make a Part 2 to the ESi showing how I addressed the problem of the the heating coming on outside of the scheduled time due to the ‘legionella’ setting being on.

Part 2 is HERE.

Plumbing & Heating

Central Heating Enhancement

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I was reading on the plumbing forums about the need for an Automatic Bypass Valve (ABV) on central heating systems and compliance with the HM Government  document – Domestic Building Services Compliance Guide, specifically the need for a ABV (page 15, section 2.0).

I have a System configuration using a Valliant Thermocompact 624e boiler, the purpose of the ABV is to maintain a consistent flow through the boiler and also should both the hot water and central heating zone valves close due reaching the set point temperature, the boiler will continue to run for 10 minutes to dissipate heat in the the boilers heat exchanger, without some form of bypass the pump will be pumping against closed valves, which is not good!

The ABV senses the increase in pump pressure and opens against a calibrated spring pressure to maintain water flow.

S Plan

My central heating system had a 15mm hand valve cracked open between the boilers flow and return for this purpose, the 28mm pipe with an automatic air vent is the feed from the boiler, the centre 22mm pipe is the return.

start

The advantage of this configuration is that the pump can not pump against a dead head, the disadvantage is that a portion of the heated water from the boiler is immediately returned to the boiler and not used the heat radiators or hot water, so I thought I’d install an Automatic Bypass Valve not realising that the boiler already had an inbuilt one until I had bought all the parts…oh well!!

The manual bypass valve was not the only thing I wasn’t entirely happy with, the main niggles were the motorised valve to the heating circuit was mounted very low and it would be better to move it higher for ease of replacement and the automatic air vent was not at the recommended height above the highest point in the system, both of these were going to be fixed at the same time as the installation of the ABV.

First job was to electrically isolate all power to the boiler and controller, once done it was a matter of draining the system down, I’m fortunate that my radiators have drain valves, this made the process very simple.

Once drained I could disassemble the pipework.

strip

I retained the hand valve for adding inhibitor and for use as a vacuum break should I need to drain down in the future.

Once the pipework was apart, I used a 22m straight compression coupling to extend the central heating pipe, lifting the motorised valve  to a more accessible location, the pipe to the automatic air vent was also extended to be 300mm above the height of the upstairs radiators.

The tricky job was to unsolder a 22mm stub which was cut to allow the pipework to come apart.

solder

With the heat mats in place, I was surprised how easy it was to desolder the stub from the feed pipe elbow, once the stub was out, I could start to  dry fit the pipework so that the ABV exit pipe was directly inline with the return from the hot water cylinders heating coil.

Once everything was aligned, I removed the head of the ABV so as not to melt anything inside it when I started soldering the fittings.

finished

This is the finished job, I used another compression fitting on the return pipework to make any future ABV replacement easier as the whole assembly can be broken down, something you cant do with soldered fittings.

British Gas replace one of the motorised valve heads and they don’t open the Honeywell junction box to connect the new head wiring, they add an external junction box which looked naff, so I remade the head cable off as it should be done.

The system now needed to be refilled, I coupled a length of 15mm copper pipe with a tundish to the original hand valve and added 1 litre of Fernox Protector F1, once done the pipe was removed, valve closed and a screw cap was fitted.

Mine is a closed system with no head tank, a filling loop from the cold water feed is used to add water and pressurise the system, as I knew there would be a lot of radiator venting, I installed a water pressure reducing valve inline with the double check and isolating valve already installed, this allowed me to set the filling pressure at 1.2bar and leave the valve open, rather than continually repressurising the system after venting air, this worked really well and saved loads of time.

loop

The picture was taken after all the air in the system was vented and the boiler pressure was 1.4bar and steady with no leaks, the loop was disconnected and capped off until next required.

To keep a beady eye on the the pressure over the nest few days I used a home CCTV system 🙂

pressure

The main problems I had was not having all the correct fittings to hand when you have to adapt from the original plan, I started the job on a Saturday morning just in case, and fortunately Screwfix is not too far away and they had everything in stock, including a new 22mm pipe slice as mine had packed it.

One thing which bothers me is that the builder used copper pipe where it can be seen and plastic where it can’t, this means that as your cutting pipe, it starts to turn inside the transitional coupling!!

I hate with a passion plastic fittings and have little confidence in them, fingers crossed they will last the test of time.

Plumbing & Heating

Hot Water to Outside Tap

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When we first moved into the house I installed an external bibcock tap which I fed by ‘teeing’ into the cold water feed line in the garage which is  used for the combination boilers filling loop.

In the previous house I had hot and cold available outside to wash the car, so the project was to do the same here. The two problems were the lack of available hot water pipes in the garage and no more wall space to add another external bibcock dedicated to hot water.

First things first, locate a source for the hot water, fortunately on the other side of the garage wall is a small utility room with a sink and plumbing for a dishwasher and washing machine.

Isolating the cold water fill to at the tank, I drained the hot water down into the utility sink and emptied the dead leg of the washer fill line using the tap at the bottom of the pipe, once this was done, I put the plug in the sink and removed the sinks waste pipe for ease of access to where I would be cutting and soldering.

Drilling a 15mm hole through into the garage from the house was easy as the internal double skin walls are built using low density thermalite block.

Pipe installPutting some tape over the open end of pipe, I pushed it through the hole into the garage where I soldered an end fed elbow with stub to a compression fitting isolation valve. From the isolation valve a stub with a tee and drain cock were soldered.  A stub pipe from the tee had a plastic stop end fitted, the pipe was then pushed back into securing clips fixed to the garage wall.

soldered bridgeUsing the pipe slicer tool shown in the first picture, I cut out a small section out of the hot pipe and put on a 15mm copper tee, using a half crossover to bridge the cold pipe, I then used a short piece of pipe to connect an elbow to the pipe to the garage.

Once the dry fit went ok, I dissembled it all to clean and flux the pipe and fittings before soldering, all the fitting were end fed here.

Once all the joints were soldered and making sure all the valves are closed, I cracked open the hot water tank fill valve and went to check for leaks after venting air from the system and running water through the garage drain valve to flush out any debris.

Pipe pull

The garage has been converted into a workshop and I didn’t want to damage any exposed pipe  when I throw stuff for storage, so the best option was to use plastic pipe and fish it behind the false wall as their was just enough room.

Drilling 110mm holes, allowed me plenty of room to push trunking lids taped together for the 4.5m run, string was attached to the end of the lid and pushed in place.

At the other end it was a pain to fish for the string using a torch, mirror and bent hook, however, once grabbed, I tied on stronger blue rope  to the string and pulled this back to secure on the pipe as shown, (the last thing I wanted to repeat fishing!).

At the utility isolation valve end, I clipped the John Guest Layflat Speedfit pipe to the wall and used a cold form bend to hold its radius and take strain off the ‘plastic to copper’ coupling.

The design to allow me to use one external bibcock tap was to use a three port valve, this suggestion came from DIYNOT plumbing forum.

SchematicParts

The pressure reducing valve, 3 port valve, double checkvalves and themostatically controlled valve were from eBay, all other parts from Screwfix.

How it works

The cold water has a local isolation valve for ease of maintenance, a double check valve stops contaminants getting back into the upstream water system, a ‘tee’ allows the pressure reducing valve to be bypassed, and if the 3 port valve is in the right position, allows full mains pressure at the outside tap for use with the hose.

The pressure reducing valve is set for 3.5bar which is the same water pressure as my unvented hot water tank, therefore the water pressure for both feeds to the thermostatically controlled valve (TCV) is the same.

The hot water also has a local isolation valve and double check valve before it feeds the TCV, the temperature of the blended water leaving the TCV is 42C.

Garage pipeAs the cold water was available, I connected this first to the valve and allowed pressure testing, the biggest problem I had was sealing the 1/2″ BSP threads on the 3 port valve.

I tried using fibre washers, PTFE tape and jointing paste but a couple of joints would still weep very slowly over time.  I searched the problem in the DIYNOT forum and the advice from experienced plumbers was to use Locktite 55 , following the instructional video on the locktite site, I applied the sealing material onto the prepared threads and it worked, no more leaks.

At the end near the bibcock tap, I used another ‘plastic to copper’ coupling and piped up and over to the hot water isolation valve.

A hot water drain cock was installed where the pipe emerged from behind the false wall so I can drain down if needed.

Hot pipeThis shows the hot water pipe coupling about to be soldered, hence the heat resisting mat, on the right of the picture is the cold water valve which is open and testing for leaks.

In the garage is another isolation valve directly behind the bibcock, this stops unauthorised use of the external tap.

The final job was to flush the system thoroughly and check that the water coming out of the bibcock tap is at the correct temperature, once proven, all exposed pipes were insulated and where the risk of damage was high, boxed in.

The most expensive part of the job was the plastic pipe as this comes in a minimum of a 25m roll and I only needed 4.5m. The option of pulling in straight lengths with a connecting coupling behind the false wall was discounted as I didn’t want any inaccessible joints, so I had no choice but to pay for more than I needed.

Apart from hassle of sealing the weeping threads, the job went well and I’m happy with the result.

Lagged pipe