Do you have to have a room thermostat

[davphi338]

All of my radiators have TRV's fitted but there is no room thermostat. Sometimes when I have the central heating on for some time the boiler trips via the overtemp thermostat.

Do you think this could be caused by not having a room thermostat and the rads turning off but the boiler continuing??

 

[kevplumb]

caused by not having a bypass i should think

 

[felix]

Your diagnosis is spot on. When all the rooms are up to temperature the TRVs close but there's nothing to turn off the boiler. At least one room needs a thermostat wired in to contol the boiler. This room shouldn't really have a TRV so turn it up to maximum and let the room stat do the job. I suggest you put the room stat in the room which takes the longest to warm up. If you need help wiring in the room stat you'll have to give us more information on what you've got already.

 

[davphi338]

Thanks for the advice guys.

kevplumb, when you say 'by-pass'. Do you mean the radiator pipework, i.e a pipe bypassing the radiator when a radiator shuts down. I remember a friend with a similar age house to mine (early 50's) saying that his heating was plumbed in a cheap way where there was just one pipe going from rad to rad. i.e a loop.

I can't see how my radiators are plumbed but could it be that radiator shutting down will stop the flow of water for the whole system and has anybody seen a house plumbed this way before.

 

[kevplumb]

take the trv off the furthest one from the boiler