Thermostats and TRVs

[Paul]

For a combi fired system - which is better - a room thermostat or TRV's??

Personally i dont like TRV's they've always seemed ugly and a lot of hassel (having to adjust each one) - are new ones better??

Also - the age old heated towel rail debate - if I have TRV's except in the bathroom (so I have the required full time 'sink' or what ever the correct phrase is) - can I leave my CH running in the summer for

*just* the towel rail - or is that silly?

bonus question - what size pipes to run the CH system in? 22mm from the boiler and spliting to 15mm to each rad or what?

Thanks in advance -

Paul.

[Andy Hall]

TRVs are the preferred solution for room temp. control, but there should also be a room thermostat to lock off the boiler when the house is warm.

It is not relevant that the boiler is a combi.

If you use good quality TRVs like Invensys, they work fine.

You should calculate the flows properly because it depends on radiator sizes and pipe lengths.

There is an application note on the Copper Development Association web site on how to do this.

.andy

To email, substitute .nospam with .gl

[anthony james]

and no radiator stats in the room with the room stat otherwise they'll conflict

we thought about this one and are going for an electric element on a timer on the towel rail which we'll run for an hour in the morning and evening in summer.

Running the CH to dry towels seemed wastful, the room stat would need to be turned up (otherwise quite often the CH would never even come on), and you'd also be partially heating the rest of the house when you didnt need to (boiler running, hot water in pipes).

[Set Square]

The solution have I adopted is to have the heating on for half an hour each morning with the (programmable) room stat turned up - but with all radiators manually turned off except one in the bathroom and one in the en-suite. Works a treat!