Thanks for the advice re TRV's, I will probably change all mine when the weather warms up again.
However, I was working for a lady today (nothing to do with heating) who mentioned that her lounge was always warm, but the rest of the house was always cold.
Her roomstat was in the lounge diner and both rads had TRV's. It sounds like this might be causing the problem. The hall rad is the only one in the house with normal valves.
A few questions.
Would removing the TRVs & replacing them with normal valves solve the problem?
Failing that, should they just be turned up to maximum & left?
Moving the roomstat into the hall wouldn't be easy. Are there wireless versions that could be fitted?
Are they baffled by curtains or other accidental insulation? Constant problem in our house - opened curtains smother TRV & rad end together, TRV feels lovely and warm and shuts off.
If this lady wants to be 100% sure of it being fixed then all you have to do is remove the thermostatic part from the valve, but its worth her just turning the valve up to full. Its also worth seing whether her sitting room is oversized for rads compared to the rest of the house in which case it will alsways heat up quicker unless you restrict the flow to these rads by closing the manual valve slightly.
You can get very good wireless roomstats that usually also have a clock on them too. The batteries last a long time and usually have a flashing symbol to indicate when they are low in energy.
In your case, despite other posts, I would always leave one rad without a TRV you can restrict the flow to this rad as described above. This rad could be in your bathroom, which as a rule of thum you would want to be slightly warm anyway.
Calum Sabey (Newark Traditional Kitchen 01556 690544)
It might be better to turn down the lockshield valves slightly so the lounge heats up more slowly, giving the rest of the house more time to warm up before the roomstat cuts off.
The system might also benefit from rebalancing so that more heat goes to the other rads.
I this case probably not[1], but it would normally be one of the "correct" options.
[1] The normal way in which this setup fails to work correctly is that it defeats the boiler interlock. The room heats until the point where the TRV shuts down, possibly leaving the main stat still calling for heat[2] - potentially overheating the rest of the house and leaving the boiler cycling when the house is already upto temp. Since the main stat will never be satisfied (unless there are additional sources of heat in the room), you carry on in this inefficient state of affairs. The usual symptom in cases like this is with the house over rather than under heating.
[2] Note that even this is a slight simplification since it does not take into account the response rates of the different stats. These have the effect of introducing a phase shift into you closed loop control system. The effect of phase shifts, if large enough, can drive the control system to instability. This could then manifest as erratic control with large swings in temperature rather than simple overheating.
If you are going to leave the main stat in that room then this is one of the things to do (or simply remove the TRV head from the valve body). The other would be to re-balance the system.
There are, and this would probably represent a better solution. The stat could be moved to the hall.
Having said all that, it sounds as if the main problem here is one of system balancing and possibly radiator sizing.
Pity, because you do get-a-little-badge-to-wear and that would look good on his puffy anorak when he's got his Ian Allan book out collecting combi serial numbers.
Thanks for all the advice chaps, turned out the sealed eystem just needed filling. Told her how to do so over the phone. She did so & bled the rads & now the house is warm all over.
Note to Alex - I didn't charge her for this, it's called customer service.
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