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?
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).
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!
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.
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.
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.
A few tests for you to do if you have a multimter. The yplan diagram is here
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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.
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.
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