My hot water is working fine, boiler fires up OK.
The problem is that my heating won't switch on.
I have a wireless thermostat which appears to send and receive the correct signal as the receiver switches on and off when I change temp of the sender and I get all the right lights.
Every now and then I can get it to come on but I have to turn temp up and down until it switches in – sometimes I have to do this for an hour or more.
I have an Ideal/Icos boiler (not combi) about 8 years old.
Any suggestions please.
Best Answer
I had this recently with a recently installed Tado thermostat and 8-year old Horstmann diverter valve.
The valve was found to be sticking, The thermostat was fine.
Yo can check this by unscrewing and lifting the diverter head off the valve, the turning the valve to the hot water position with pliers.
In my case, the radiators started to warm immediately. Putting the head back on the valve reinstated the hot water only situation. Moving the manual override lever on the valve head had no effect.
A new diverter valve fixed the problem.