DIY Doctor UK DIY Forums

hi, theres a fault with my central heating,i have a conventional system.the boilers a glowworm and the controls are drayton. i thought it was the room thermostat as i couldnt turn temp down.it keeps firing up to 23 degrees even though its set and clicks to under 20 .i even turned heating off at the programer next to the tank but the rads are still running hot.i still have hot water as i normally have both ch and hw on at same time.what is a actuator? and a 3way valve?please help me to find out problem. thank u

First you have to discount a frost stat is not over riding the heating controls and firing the boiler even when the programmer is in the off position.

If this is not the case, it may be the three way valve if fitted may be jamming and keeping the heat on. Another possibility is incorrect wiring or even a faulty room stat.

The trouble is, unless you know a little about heating systems, because of the number of possibilities, it may be difficult to nail down the problem.