Heating does not turn off all the time

[lmhud]

Heating does not turn off when we lower the thermostat, also it is set to turn off at 22:00 each evening and most of the time it doesn't and I have to turn the boiler off and then back on when it then resets and is okay until its due to go off the next evening.

The timer is a Sunvic, The Thermostat and the 3 port valve are both Honeywell. The boiler is a Viessmann.

The boiler was new 2 years ago and was fine about 10 months ago we got the 3 port valve moved from under a bedroom floor next to the boiler in the garage, at the same time we asked him to put in the new thermostat, new timer and a new 3 port valve, timer and thermostat are new but looking at the 3 port valve it looks second hand could this be the problem ? sorry to go on a bit.
The guy that did all the work now lives in Australia so getting him back is a no go, any help appreciated.

 

[jackthom]

It sounds like a wiring problem but you would need a multimeter and be confident to make some mains voltage measurements to sort this out yourself.

If you are OK with this, a photo of the inside of the wiring centre would be helpful.

 

[lmhud]

View media item 86380

 

[jackthom]

Can you also show a view from slightly above and right a bit? So the wires going into the top of the strip are clearer.

 

[lmhud]

Can you also show a view from slightly above and right a bit? So the wires going into the top of the strip are clearer.

Thanks for the reply Jack. Hope this helps.
View media item 86392

 

[jackthom]

Yes there's still lots of spaghetti but it's clearer.

Can you measure the voltage between Neutral (Blue on #2 counting from the left) and the 3-port valve white wire (#5 from left) ?

When the room thermostat is set high and calling for heat this should be ~230V and when the stat is set very low, ie satisfied, the voltage should be closer to zero.

This is when the programmer has been set for heating to be ON.


When heating is programmed to be OFF the above voltage should remain very low, regardless of the thermostat setting.

 

[lmhud]

Yes there's still lots of spaghetti but it's clearer.

Can you measure the voltage between Neutral (Blue on #2 counting from the left) and the 3-port valve white wire (#5 from left) ?

When the room thermostat is set high and calling for heat this should be ~230V and when the stat is set very low, ie satisfied, the voltage should be closer to zero.

This is when the programmer has been set for heating to be ON.


When heating is programmed to be OFF the above voltage should remain very low, regardless of the thermostat setting.

That be a problem as I don't have a voltage testerand am not 100% sure of what to do. appreciate your replies though

 

[jackthom]

No problems. Unfortunately it would be near impossible to find out what's going wrong in there without a multimeter.

 

[leakydave]

Is a FROST STAT keeping the boiler running when you turn it off?

 

[lmhud]

If I can get someone to test the connections what would we be looking for using the info you gave and what could be wrong?

 

[lmhud]

Is a FROST STAT keeping the boiler running when you turn it off?

Not sure we have a frost stat ?

 

[leakydave]

Probably be a good idea with boiler in the Garage which I assume is an unheated space.

 

[lmhud]

Probably be a good idea with boiler in the Garage which I assume is an unheated space.

Where and how would i put a frost stat ?