Heating comes on when not required

[flinty]

Hi,
my central heating is coming on when it is not required.
When the electronic programmer tells the heating and hot water to come on but the thermostat is down lower than the room temperature the radiators still heat up.
I have checked the three port valve and that is moving freely across and have also checked that it moves to the on position when the thermostat is turned up and goes back to the off position when the thermostat is turned back down.
sometimes the radiators will not heat up but if the stat then calls for heat they will not turn off again.
Any ideas please?

 

[Agile]

You have not explained the history of this installation!

Is this where you live? Have any changes been made?

My first guess is the valve is not sealing properly perhaps because the ball has come loose?

Tony

 

[EliteHeat]

sometimes the radiators will not heat up but if the stat then calls for heat they will not turn off again.

huh?

 

[flinty]

The installation is exactly as it was installed by the builders 10 years ago. It's my house.. a bog standard 4 bed detached slum.
The pump has been replaced as has the three position valve.

 

[flinty]

sometimes the radiators will not heat up but if the stat then calls for heat they will not turn off again.

huh?

The radiators don't always heat up when no heat has been called for by the thermostat, but sometimes they do.

 

[flinty]

My first guess is the valve is not sealing properly perhaps because the ball has come loose?

Tony

Any (clean) suggestions as to how I can check if the ball has become loose?

 

[wilhelm]

then the valve actuator is fekked. change it.

 

[Agile]

You seem convinced that the valve actuator is moving correctly.

If thats the case then the only logical reason for the problem would be the ball is not sealing because its come loose/disintegrated/or there is a chunk of dirt blocking it.

Only way is to drain and open and inspect the ball.

How long ago were the pump and valve changed?

Tony

 

[flinty]

The valve was changed 4 months ago because the previous one was faulty and not moving across to allow the central heating to come on.

 

[Softus]

Did the person who changed the valve also clean the system and add a chemical inhibitor when refilling?

Please could you read this and provide the information it asks you to provide?
_______________

sometimes the radiators will not heat up but if the stat then calls for heat they will not turn off again.

huh?

I read that as meaning that the problem [of the radiators heating up when they shouldn't] doesn't always occur, for example when the whole system has been off for a while, but that once the heating circuit has been on then the valve doesn't shut it off again.

This symptom is consistent with Agile's suggested cause, but there are other possible causes.

 

[Agile]

Because you did not volunteer the information about when the valve was changed I have to ask you another question as it may be relevant.

Was the WHOLE valve changed? That means the actuator AND the body?

Has the valve been connected the correct way round?

Is the water flow through the valve in the correct direction?

Tony

 

[gas4you]

New valve should still be under warranty then. Get installer back to check it.

 

[flinty]

Was the WHOLE valve changed? That means the actuator AND the body?

Has the valve been connected the correct way round?

Is the water flow through the valve in the correct direction?

Tony

Yes the whole valve was changed and yes the water flow is deffinately correct.

Today I managed to check after the heating had shut off and the valve hade not reset to the default 'water only' setting so it does look like the valve has gone tits up.

 

[Agile]

I think that it sounds more like a wiring fault than a failed valve.

Have you electrically checked the cylinder stat on NO and NC ???

Tony

 

[gas4you]

Whatever! Still the same reply; get the engineer who fitted it back to correct or replace. (I really wanted to say tw at instead of engineer, but couldn't bring myself to do it )