Central heating - does this sound OK?

[defblade]

My MiL has just bought a bungalow. It's got oil fired central heating, with a Worcester boiler in the basement and hot water tank in the airing cupboard. It's got a programable timer, which seems to be working as intended. So fine so far.

But ALL the radiators have thermostatic valves on and there's no room thermostat anywhere. I have it in my head that you shouldn't have thermostatic valves on all the the radiators in a system - at least one should be plain valved (I could well be wrong here....). Also, how will the boiler know to switch off when correct room temp is reached; apart from when the boiler thermostat is tripped by the water heating up too much overall (and presumably leading to on-off cycling as the temperature at the boiler thermostat falls?).

There's going to be a fair bit of redecorating done before she moves in properly, so now's the time to this right if it's not already....

Thanks in advance for any help.

[Herbie58]

Emm, not sure, all of my central heating radiators have had a temp control on them, the boilers have had their own temp control, which is for overall max temp (IIRC). Never had any issues, so it all sounds normal to me, but I'm no plumber!

[TooLateForAName]

Is there a bypass valve near the pump/boiler?

[defblade]

TooLateForAName said:

Is there a bypass valve near the pump/boiler?

No idea. What would it look like?

[ACEparts_com]

You need a thermostat and one rad at least with no valve. System will then be very efficient. Without a thermostat and bypass (rad with no valve) the thermovalves will BUZZ/bang like mad as they try to shut with the pump still running as it does in this st house we're currently living in.

[Ferg]

I would definately fit a room thermostat.
Take the head off the raiator valve in the space with most air changes (Hall?) and fit it in there. You are spot on that it will just heat up the primaries then cut out on the boiler thermostat.

The issue above is slightly different. That sounds like the system hasn't been provided with a bypass to cope with a pump overrun. Oil boilers don't overrun the pump simply because the heat exchangers are man enough to take a bit of heat-soak, unlike the modern gas boilers.

[defblade]

Thanks folks - looks like I'll have a bit of plumbing and wiring to do then (might try and sell her on a wireless thermostat though to save me a lot of work ).

[Ricky_M]

Was going to recommend a wireless stat, so much easier to install. It is actually a building reg requirement to have a room stat, but so many properties don't. Mine included, I've got it on the wall, just havn't got round to wiring it up!