Heating Won't Come On But Water Does!

[Scarlett]

The radiators are off but the water is still heating up so the boiler obviously works- any ideas what I can do to wake it up? It's has central heating and quite an old boiler but was serviced this month and is fine apparently!

[jennyjoan]

can you make sure the radiators are not off at the side of them - you know the little nozzle

[jennyjoan]

You could have an air lock somewhere

[emeritus]

Do you have a room thermostat ?. Check it hasn't been turned down accidentally. Check the Time clock as well to make sure its in an on position.

[emeritus]

Also could be the Pump

[vetuste_ennemi]

Do you have a thermostat to control room temperature when the radiators are on, Scarlett? If so its batteries may need replacing.

[TWR]

Could be an imbalance in the rads,
Has it valves on the Rads? they may be faulty,
As Said, air locks easy to vent each rad Scarlett,
Contact the Service agent and say that your system was ok until it was serviced, they should rectify at no cost.

[bhg481]

The most likely problem is the diverter valve, which will be in the airing cupboard near to the pump. Systems are normally set to heat the hot water cylinder when the heating first switches on; when the hot water has reached the set temperature a motorised valve diverts the water from the pump to go through the radiators, instead of the hot-water cylinder. This valve is easily recognised by the fact that there is one pipe in (from the pump) and two pipes out (one to the cylinder and one to the radiators) and it has a lever sticking out of it to allow you to operate it manually, in case it sticks. Find the valve and move the lever - it will be stiff and you might hear the motor turning as you move it. Once moved it should operate normally; if it doesn't it will need replacing - not a difficult/expensive job.

[TWR]

The valve your on about Bhj, I attempted to replace our's with difficulty, there was no movement in the pipes & the job which should be completed under an hour took hours, I would still recall the service person to sort it being that it has just ( Month) been serviced.

[Garaman]

I would just make sure it isn't something silly as others have said, like the thermostat set incorrectly, or its batteries OK if it has them, then ring the service company.

[The Builder]

I think bhg is right about the diverter valve (automatically selects hot water or heating, depending on which is calling.)

If you have a combi boiler, it's inside the boiler casing, so I would suggest that you have someone take a look at it.

[Scarlett]

Many thanks all, I will get the boiler man to come and have a look as I can't even open a tin of spam!

[gness]

Exactly the same thing happened to me, Scarlett...immediately after I'd had the yearly service....and it was the diverter valve.....but Worcester Bosch who'd done the service told me it was because it was winter and the water was colder coming into the house?????
I had to pay someone else to sort it.....I'd rather give Worcester Bosch a tin of spam to open than let them near my boiler again...... :-)

So don't let anyone fob you off with the cold winter water waffle!...Gx

[-Talbot-]

Agree with bhg.

[Tilly2]

Same happened to us on Christmas Eve. Just before the pump seized up!