Potterton Combi boiler not firing for DHW

[Yankbo]

Potterton gold Combi boiler is firing and heating CH but not for DHW.

The burn on light is not coming on at all for DHW leading to a lack of hot water.

Any ideas on what this could be?

 

[cross thread]

Probably hot water sensor ,should put a red light on when water is calling ,

 

[Deleted member 267285]

Is the tap symbol showing on the boiler?

 

[Yankbo]

Tap symbol is showing when hot water taps are turned on. Only the burn light failed to come on

I turned the boiler off including power supply for around 10min while looking over the circuit board for any signs of wear and it has now started working again. So completely unsure of what the issue was/is.

 

[Deleted member 267285]

So completely unsure of what the issue was/is.

If the tap symbol showing, then it’s seeing the demand, could be flow sensor or diverter issue.

 

[Yankbo]

Noticing today that while the symbols are all showing correctly the water is not getting up to temperature (e.g if DHW is set to 55 degrees the boiler is only showing ~45 degrees upon heating)

I had the heat exchanger replaced around a month ago as it was gunked up and it has worked fine since then.

 

[ianmcd]

Most likely the diverter valve cartridge

 

[Yankbo]

Do you think it is stuck in the CH position? In DHW only mode I get the same lukewarm water through

 

[ianmcd]

Do you think it is stuck in the CH position? In DHW only mode I get the same lukewarm water through

There is two common faults with them , the plastic cartridge breaks up, or the diverter gland passes and water gets into the actuator motor and the motor fails, you do not have to be gas safe registered to remove the outer cover and have a look, the motor is simply held in with a large circlip take it out and see if you can see signs of it having water damage , usually very obvious, or post pics of it

 

[Yankbo]

There is two common faults with them , the plastic cartridge breaks up, or the diverter gland passes and water gets into the actuator motor and the motor fails, you do not have to be gas safe registered to remove the outer cover and have a look, the motor is simply held in with a large circlip take it out and see if you can see signs of it having water damage , usually very obvious, or post pics of it

Apologies for the delay in updating but the boiler is now working again!

I took your advice and had a look at the valve cartridge which was broken up and stuck inside the assembly. I had to wait over Xmas for parts to arrive but now have replaced the entire assembly/motor/cartridge (as the parts only cost about £40).

Massive thanks to yourself and CBW for your knowledge, as I would have had no idea where to start looking to be able to fix this myself!