Removing/Disabling TRV's

[freezing butt]

Hi all,

I have just moved house and all the rads including the one in the passage where the thermostat is sited have TRV's fitted.

Our old house had good old fashioned radiators without TRV's and were hot all the time until we turned the stat down and that is what I would like to get back too in certain rooms.

So, my question is................can I disable a TRV without having to replace it so it is on/open all the time or do I need to replace the whole unit?

If the only option is replacement is it just a case of draining down, removing the TRV and replacing it with a conventional valve?

Any advice would be apprieciated, thank you in advance.

 

[stevetheplumber]

taking the head of disables them although leaving them on full usually works as well

 

[doitmyself]

Our old house had good old fashioned radiators without TRV's and were hot all the time until we turned the stat down and that is what I would like to get back to in certain rooms.

I know it's your call, but why do you want to do this?

 

[Dennis]

taking the head of disables them although leaving them on full usually works as well

'Full' tries to get room heat of [IIRC] 93 degrees f on mine!

 

[WHPES]

If your rooms aren't warming up it is that the system needs balancing and not the fault of the TRVs. With the TRVs on full it is the same as a manual valve fully open.

 

[freezing butt]

I know it's your call, but why do you want to do this?

Thanks for all the replies guys but as "doitmyself" asked why I will explain.

First of all all our rads are set to "max"

The system starts off fine once the timer kicks in, all rads become very hot, however in our lounge/dining area we have 2 x rads, once the temp starts to rise it seems they are battling each other to come on/go off, what tends to happen is the dining area rad is always boiling hot and it seems to me the lounge area rad can sense this temp and shuts down, however the room is still cold.

Also we have a rad at the bottom of the stairs and one at the top, as we all know hot air rises so what happens is the hot air from downstairs rises up so the rad at the top is always off because it is sensing the hot air coming up, however the hot air coming up the stairs is not enough to heat the upstairs landing.

Maybe they do need a balance, what is the best way to balance a system with these TRV on?

 

[fuzzy]

i suspect it just wants balancing. The TRV's should actually help the problems that you are expereincing not the cause of

fuzz

 

[doitmyself]

Thanks for all the replies guys but as "doitmyself" asked why I will explain.

Thanks.

1. Do all your radiators have TRVs, or is there one rad without a TRV, where the wall stat is situated?

2. Are the TRVs set to max to try to overcome the problem or because the rooms are not warm enough?

3. The problem with the upstairs rad turning off too soon is unlikely to be due just to the hot air rising. You say that the landing is not hot enough, so the TRV should still be keeping the rad open.

4. Poor balance is very likely to be the cause of the problem.

what is the best way to balance a system with these TRV on?

Read How to balance a CH system for detailed instructions.

 

[Blackcatgas]

If your rooms aren't warming up it is that the system needs balancing and not the fault of the TRVs. With the TRVs on full it is the same as a manual valve fully open.

+1 WHPES is correct. unless the pin is partly jammed and they are stuck on say setting 3. Keep the trvs, they are your friend.

 

[charitynjw]

Just a thought, guys.
TRVs don't react directly to room temp, they sense the water temperature at the radiator.

 

[Blackcatgas]

Just a thought, guys.
TRVs don't react directly to room temp, they sense the water temperature at the radiator.

Wrong. Google how one works

 

[fuzzy]

Just a thought, guys.
TRVs don't react directly to room temp, they sense the water temperature at the radiator.

This would stop the rad from warming the room

 

[doitmyself]

TRVs don't react directly to room temp, they sense the water temperature at the radiator.

Manufacturers go to considerable lengths to ensure that TRVs do not react to the water temperature, only to the air temperature.

On a Drayton TRV4 the water temperature only affects the room temperature by a maximum of 0.8 degrees.

 

[freezing butt]

Thanks.

1. Do all your radiators have TRVs, or is there one rad without a TRV, where the wall stat is situated?

2. Are the TRVs set to max to try to overcome the problem or because the rooms are not warm enough?

3. The problem with the upstairs rad turning off too soon is unlikely to be due just to the hot air rising. You say that the landing is not hot enough, so the TRV should still be keeping the rad open.

4. Poor balance is very likely to be the cause of the problem.

Read How to balance a CH system for detailed instructions.

Hi again,

1/ Yes, all the rads have TRV's

2/ Yes, all set to Max because we are cold, especially downstairs.

3/ Maybe I did not explain myself, the area the upstairs rad is sited in is warm and I think this is aided by the warm air rising, so the rad upstairs is generally cold/warm when you touch it and I am assuming it thinks the house is warm enough, however move further down the passage and once again its cold due the upper rad not being very hot.

4/ Hope so, thanks for the link to balance the system, I must admit I generally just bleed air out of the system as and when so maybe a full balance is what is needed to set it up, the house was empty for 6 months before we moved in and the heating was turned off so a little TLC would not go a miss.

If I post on here Monday thanking you all from bended knees because we are warm you can consider yourselves heros, if however I post telling you all I am still cold following the system re-balance I shall sign up to another forum where they know what they are talking about

I do have another question about the system because I do not have a tank in my loft but to avoid getting off topic I will start another thread.

Thank guys, talk soon

Thanks.

1. Do all your radiators have TRVs, or is there one rad without a TRV, where the wall stat is situated?

2. Are the TRVs set to max to try to overcome the problem or because the rooms are not warm enough?

3. The problem with the upstairs rad turning off too soon is unlikely to be due just to the hot air rising. You say that the landing is not hot enough, so the TRV should still be keeping the rad open.

4. Poor balance is very likely to be the cause of the problem.

Read How to balance a CH system for detailed instructions.

Hi doitmyself,

Thank you for the link re the balancing however I have a couple of questions.

3/ It says "open all LS (lock shield?) valves fully, remove all TRV heads and open all manual rad valves fully"

I am at work at the moment and can't remember but am I not right in saying the TRV replaces the LS valve? I thought the other end of the rad had the plastic cover on it that you removed and adjusted the nut with a spanner.

If this is the case do I fully open both ends of the rad?

6/ "Adjust the bypass (if fitted)" what is a bypass and where would I find it?

9/ "close all the lock shield valves and leave off the TRV heads" does this mean I leave the other end of the rad fully open?

Sorry if they are dumb questions but I did a proper apprenticeship, I am an electrician (ducks and waits for the abuse)

All joking a side if you could clear up these matters for me I could be in business.

Thanks

 

[doitmyself]

1/ Yes, all the rads have TRV's

I asked if you have a room thermostat and then re-read your first post where you said that you do. You should never have a TRV in the same area as a wall thermostat; one will stop the other one working. Set the wall stat to 20 and the TRV to 22 and the room will heat up to 20C, when the wall sat will turn the boiler off. If you set the TRV to 20 and the wall stat to 22, the TRV will shut the radiator off, so the room will never reach 22. Result; the boiler runs continuously.

Replacing the TRV with a wheel valve is the best solution. But setting the TRV to Max or removing the head are acceptable alternatives.

Maybe I did not explain myself, the area the upstairs rad is sited in is warm and I think this is aided by the warm air rising, so the rad upstairs is generally cold/warm when you touch it and I am assuming it thinks the house is warm enough, however move further down the passage and once again its cold due the upper rad not being very hot.

Got you. If you don't want to move the rad down the passage, you may be able to get a remote sensor for your TRV. Drayton do them for the TRV4; they come with 2m or 6m capillary tube connections.

It says "open all LS (lock shield?) valves fully, remove all TRV heads and open all manual rad valves fully"

I am at work at the moment and can't remember but am I not right in saying the TRV replaces the LS valve? I thought the other end of the rad had the plastic cover on it that you removed and adjusted the nut with a spanner.

All rads have two valves. At one end there is either a manual wheel valve or a TRV. At the other end is the lock shield valve, usually under a plain cover.

If this is the case do I fully open both ends of the rad?

Yes; and remove the TRV head.

"Adjust the bypass (if fitted)" what is a bypass and where would I find it?

It's a pipe immediately after the pump which connects the flow directly to the return. You say you don't have a tank in the loft so you may not have a bypass.

Make and exact model of boiler please.

"close all the lock shield valves and leave off the TRV heads" does this mean I leave the other end of the rad fully open?

Yes. that's why it says leave the TRV heads off (not just set to MAX)

 

[freezing butt]

I asked if you have a room thermostat and then re-read your first post where you said that you do. You should never have a TRV in the same area as a wall thermostat; one will stop the other one working. Set the wall stat to 20 and the TRV to 22 and the room will heat up to 20C, when the wall sat will turn the boiler off. If you set the TRV to 20 and the wall stat to 22, the TRV will shut the radiator off, so the room will never reach 22. Result; the boiler runs continuously.

Replacing the TRV with a wheel valve is the best solution. But setting the TRV to Max or removing the head are acceptable alternatives.

Got you. If you don't want to move the rad down the passage, you may be able to get a remote sensor for your TRV. Drayton do them for the TRV4; they come with 2m or 6m capillary tube connections.

All rads have two valves. At one end there is either a manual wheel valve or a TRV. At the other end is the lock shield valve, usually under a plain cover.

Yes; and remove the TRV head.

It's a pipe immediately after the pump which connects the flow directly to the return. You say you don't have a tank in the loft so you may not have a bypass.

Make and exact model of boiler please.

Yes. that's why it says leave the TRV heads off (not just set to MAX)

Thanks for all of this doitmyself, all understood so far and I will post the boiler details when I get home however I have what I think they call a sealed system?

My boiler is in the garage, the hot water tank sits on the floor beside it and the pump is mounted inside the boiler, I have a pressure gauge on the front of the boiler and I was told that when the needle drops below the red line I have to turn a tap that is sited on a peice of braided hose to top the system up.

I have been doing the above when the pressure drops and it seems to to the job.

I must admit it takes a bit of getting used too though as it is totally different from my last house/system.

Make and exact model of boiler please.

Hi doitmyself,

Make and model of boiler are as follows:

Potterton Performa System 24 HE

Its a wall mounted powered flue condensing boiler and it has a built in by pass which answers my question re the balancing.

Hope this helps, I look forward to your reply.

Thanks

 

[Dennis]

Hmmm..... Having to regularly re-pressurise the system does not sound good to me....

 

[freezing butt]

Hmmm..... Having to regularly re-pressurise the system does not sound good to me....

No??? I suppose on average I give it a quick burst to top it up about once a month, the pressure does drop but I like to do it in case i forget and it drops too low.

 

[fuzzy]

i presume its a system boiler then, with an unvented cylinder? what make is the cylinder?

 

[freezing butt]

i presume its a system boiler then, with an unvented cylinder? what make is the cylinder?

Correct Fuzz,

The hot water cylinder is an Ariston unvented storage tank.

 

[doitmyself]

Make and model of boiler are as follows:

Potterton Performa System 24 HE

Its a wall mounted powered flue condensing boiler and it has a built in by pass which answers my question re the balancing.

Yes, you have a sealed system.

You can ignore the bypass adjusting bit in the balancing instructions.

Although it is not stated in the Installation Instructions, you can assume that the correct temperature differential when balancing is 11C or as near as you can get.

 

[LIFES A GAS]

You could have other problems too, first off, standard TRV's are positioned low down & close to the rad, not the ideal position for controlling the temp of the room, they do not snap open/closed as the temp rises or falls, they are controlled by a wax or liquid filled head which as it expands or contracts adjusts the valve flow, the time taken to open/close fully is not that fast.
Your rads may be too small or wrongly positioned, your room thermostat may not be in the best position, remember the room thermostat will turn all the heating off when it is satisfied no matter what setting the TRV's are on.
You could consider zoning your system, this would involve adding zone valve(s) and extra room thermostat(s), all depends on your current layout. Hope this helps,
Martin

 

[charitynjw]

Yes, you have a sealed system.

You can ignore the bypass adjusting bit in the balancing instructions.

Although it is not stated in the Installation Instructions, you can assume that the correct temperature differential when balancing is 11C or as near as you can get.

I was told that the recommended temp diff is 20C on condensing blrs (to maintain a low return temp of <50C - has this changed?

 

[LIFES A GAS]

I was told that the recommended temp diff is 20C on condensing blrs (to maintain a low return temp of <50C - has this changed?

Not sure, but I know when condensing boilers were first used by BG (over 30 years ago) those older boilers could not modulate so it was a case of fitting over sized radiators and operate the boiler at a much lower temp to increase the time the boiler spent condensing, today its possible to run boilers at high temp as the boilers can modulate.
Martin.

 

[freezing butt]

Yes, you have a sealed system.

You can ignore the bypass adjusting bit in the balancing instructions.

Although it is not stated in the Installation Instructions, you can assume that the correct temperature differential when balancing is 11C or as near as you can get.

thanks doitmyself and all the rest of you.

I can confirm I spent a large part of yesterday balancing the system as per the link above and it has made a big difference.

Its a little early to tell if it solved the problem 100% because the weather has been so mild over the last 24 hours but we shall see how it stands up in the next cold snap.

I will keep you posted

 

[doitmyself]

I was told that the recommended temp diff is 20C on condensing blrs (to maintain a low return temp of <50C - has this changed?

Not sure, but I know when condensing boilers were first used by BG (over 30 years ago) those older boilers could not modulate so it was a case of fitting over sized radiators and operate the boiler at a much lower temp to increase the time the boiler spent condensing, today its possible to run boilers at high temp as the boilers can modulate.
Martin.

The important temperature is the Return temperature. This has to be less than 55C or the boiler will not condense.

If the flow temperature is 11C higher, i.e. 66C, the radiators will only give off 75% of their stated output. If the flow is 20C higher, i.e. 75C, the output will be 85%.

I can't prove it, but my suspicion is that most condensing boilers rarely condense as they are run at too high a temperature. This is because the installation was not designed with condensing boiler in mind, i.e oversized radiators to allow for the reduced output. This will be particularly true where the condensing boiler is a replacement for a non-condensing.