Thermostat problem.

[mac1567]

Hi. I have a probelm with my gas central heating if anyone could suggest a fix for it. When i turn the heating on by the Thermostat (pic below) to just heat the water and not the radiators the radiators now come on. My boiler is a Baxi boiler (old i know) does anyone think it could be the Termstat?

Thanks all

 

[aggis]

This thermostat should just operate your radiators, not hot water. turn it up rads come on, turn it down below room temp, & they go off, when the time clock is on/calling.
Hot water will be operated by the clock & if the cylinder has a thermostat [ on the side about 10- 18" from the bottom] should be set 55c or 140f.If turned up high & no hot water, could be a motorized valve, you'll need a plumber to lool at it.

 

[mac1567]

Hi thanks for the reply your right sorry. The problem is when the thermostat is turned down and the clock kicks in for firing up the boiler the rads come on when they shouldn't. Do you think this is the termostat that seen its day.

 

[PlumbBobBob]

sounds like the three way valve or two way if those are fitted is in need of fixing. best to get a heating engineer in to have a look.

 

[aggis]

The only way to check the roomstat, is to turn the power off remove the front of the stat, could be upto 4 wires, earth, live, neutral & switched live to the boiler/pump. turn on electric with a neon screwdriver there should be power to live, with clock turned on. if the stat is turned down there should be no power to switched live, turn the stat up & there should be power to sw live. if there is power to the sw live all the time, the stat is faulty.
If the r/stat is ok, then does the system have a 3 way valve or zone valves?
If not sure, is there a cylinder stat on the side of the cylinder?
If there isn't, I'm guessing your boiler is at the bottom of the house, therefore your problem lies with a faulty anti-gravity valve, plumber req'd.
If there is a cylinder stat you might have a 3 way valve might be in your cylinder cupboard, 3 pipes into it, looks like a T with a box on it. 1 pipe goes into the cylinder, the pipe at the opposite side is the heating supply, now if this has a gate valve on the heating side, turn it off. If this stops the radiators getting hot, you need a new 3 way valve.
If it's zone valves there will be 2 valves, identify the heating valve, if it has a gate valve next to it, turn it off, if rads stop getting hot, new 2 port zone valve req'd.
Hope this helps.All in all you probably need a plumber

 

[mac1567]

Thanks for the advice thats great and gives me good places to start.

Thanks all