Potterton Promax combi 24he A, hot water problems!!!!

[TomP51D]

This boiler works absolutely fine when running on heating mode. When you put the hot water on it runs fine for a while but the temperature goes up to 90 before cutting out causing the water to go cold, once it cools back down again it fires up for a period of time before repeating the same thing over and over. The flow rate around the property seems good and isn't effected when the water drops out and goes cold

I got called out for this fault and also a leak. the diverter valve cartridge was leaking and so was the DHW temperature sensor. the water from the cartridge had managed to find its way into the diverter motor head and had also run over the pressure sensor. So I figured why mess around, the main cost was the cartridge and head, so I may as well replace the temperature sensor which I thought was probably the part causing the hot water fault and the pressure sensor while I was doing it all.

I am totally not familiar with these boilers and im glad im not as the customer said it was only just 2 years old. cheap boilers maybe?

I tried to contact potterton tech while I was there but 40 minutes later I gave up on them. So I thought I would see if anybody had any ideas or suggestions before I go back? Didn't know if these boilers had any common faults?

I did wonder if it had something to do with the hall effect sensor or maybe the PCB is knackered.

Thanks for your help

 

[Gasguru]

Sounds more like the plate heat exchanger is blocked. Was the system water black...diverters should not fail so soon.

Join the Combustion Chamber.

 

[TomP51D]

I figured the plate heat exchanger should be ok as the boiler is still virtually new, heating water seemed clean and the boiler had a magnaclean fitted when the boiler was installed. Also has a scale reducer correctly fitted on the cold supply. pretty sure I could smell the inhibitor in the system. Presumably was correctly flushed when installed but I have no idea.

New to the site, whats the combustion chamber?

 

[Gasguru]

Never assume anything

Feel the flow and return pipes across the secondary hex....if the flow is red hot and the return significantly cooler that would indicate a slow pump, blocked heat exchanger etc

The CC is a trade only forum, join here....


//www.diynot.com/forums/viewtopic.php?t=114690&start=0