Radiator thermostats


Hi,
We have one room upstairs that's always too hot. We've got the usual twist valve on the bottom of the rad, but the room is too cold if we turn it off. Was thinking about those replacement valves with the thermostsat in, are these effective? Do we have to fit them to all rads or just the ones in need? Oh, and how big a job is fitting? Do I have to drain the system first?
Thanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
HI TRV's (thermostatic radiator valves) are IMO the easiest way to regulate the temperature in your home and save heating costs. They are very reliable and really should be fitted to all but one radiator (normally the bathroom).If you had them on every radiator then if the house gets hot all the rads switch off and the water in the system cannot circulate. Others on group may know current regs for this but as a DIY job I think the choice is yours on how many to replace, As to replacement you WILL have to drain down the system and remove the rad.(yes I know some tradesmen can do it in situ but this is a DIY NG) Next job is to remove the valve from the feeder pipe and the tail from the rad. This may mean having to cut the feeder pipe as the valve is sealed with an olive and locknut.Again this is worst case scenario some TRV's have the size fittings and you may be one of those lucky people who get away with using an old olive,but be prepared to shorten the feed pipe. The tail screws into the rad usually secured with PTFE tape and/or Boss White sealing compound.To remove you will need the correct size spanner or Allen Key. As you can see a time consuming job so why not clean the system while it is drained down (flush it out) and do all the rads you need at the same time. HTH CJ

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

That should be all but the radiador where the room stat is, usually the hallway
<If

The bypass. May or may not be needed. It depends on the setup.

A drain down is needed, the TRVs are usually a straight swap when the system is drained down.
Adam
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
[Default] On Sun, 28 Mar 2010 00:04:39 -0000, a certain chimpanzee,
keyboard and wrote:

I must remember to read all the posts in a thread before replying; I've just said the same thing only 11 hours later!

Can it be done with one of those pipe freezing kits? I've _replaced_ a TRV without draining down.
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
[Default] On Sat, 27 Mar 2010 23:05:41 -0000, a certain chimpanzee,

They should be fitted in every room except the one with the room 'stat in (usually the hall or the living room).

Not if the room 'stat turns off the boiler first. If it doesn't then the boiler is on all the time the programmer says it is, and you're wasting incredible amounts of gas (or oil or whatever).
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
randomly hit the keyboard and wrote:

Thanks guys, I've just discovered that all the rads are hot even with the wall thermostat turned down fully. This might explain why this particular room is too hot. It's got the airing cupboard one side, bathroom the other (it's one of those systems where the bathroom rad is on constantly), plus the rads don't seem to be turning off no matter what the main thermostat is telling them.
The programmer is set to "continuous" for heating and water, but the thermostat doesn't seem to be controlling anything. We have a problem!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
randomly hit the keyboard and wrote:

What system do you have?
http://wiki.diyfaq.org.uk/index.php?title ntral_Heating_Controls_and_Zoning
You are showing symptoms of a dodgey mid position valve. Test the roomstat by turning OFF your HW at the programmer and then see if you can get the boiler to fire up using the room stat. If a 3 port valve is stuck at the mid position then the CH will get hot everytime the HW is called for regardless of the room stat position.
Adam
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
randomly hit the keyboard and wrote:

I'm not sure. We have a boiler in the kitchen which supplies the water and the heating, a hot-water-tank in the airing cupboard along with the programmer, and a wall mounted thermostat in the hallway. That's it, really. I've left the programmer on "continuous" and was under the impression that the boiler would only heat the rads or the water when they needed it.....
In your scenario, do you mean I should turn off the heating at the programmer, or the hot water? The rads are still hot despite the thermostat being turned all the way down, so I'll go and turn the heating OFF at the programmer and see what happens.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
randomly hit the keyboard and wrote:

Have you any zone valves in the airing cupboard?
Adam
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
randomly hit the keyboard and wrote:

We've got a 3-way valve that was replaced a few months ago.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
randomly hit the keyboard and wrote:

A Y Plan set up?
Try calling for HW and CH on their own and see what happens. You should be able to get both HW and CH to work independantly of each other.
Adam
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
randomly hit the keyboard and wrote:

I've turned the CH "OFF" on the programmer but am waiting to see if the rads cool down.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

OK, the programmer has been OFF for the CH for half an hour and all the rads are all still red-hot.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Are you still calling for HW?
Adam
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Yes. Kept the CH off at the programmer, then turned the hot water off at the programmer an hour later, and the rads went cold. Turned the HW back on, rads got hot again. CH still off at the programmer.
No idea how this system works, but I can hear the valve motor run when I turn the hot water on at the programmer, but there's nothing when I turn the heating on, whether the water is on or off.
To be honest, I'm not sure if this is recent, or whether it's been since we had work done on the system. We had a problem where the boiler stopped firing up, they replaced the 3-way valve and the programmer (under insurance), but now I'm wondering whether they've wired everything up correctly or whether we've had a failure since then. It's only since the weather is getting warmer that we've noticed how hot this room is.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

A few tests for you to do if you have a multimter. The yplan diagram is here http://www.diyfaq.org.uk/docs/Sundial-Wiring-Rev1d-2nd%20Edition.pdf
Call for HW only at the programmer. Then test the white and grey wires to the midposition valve. These should be at 0 volts if the boiler is running and should not be affected by the room stat. It is important that the clylinder stat is calling for heat.
Then call for HW and CH. The white wire should go to 240V when you turn the roomstat up.
Adam
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I didn't fancy sticking probes into live electrics(!), so we called the fella out again... it was the mid-position actuator apparently, he just swapped it and all is well. Because it was one of the parts he'd swapped a few months back, it was covered. Thanks for all the help.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.