Potterton Promax SL 12 Fires up but cuts & locks out after a few minutes

[Richard Campbell]

I’ve got a Potterton 12SL Promax condensing CH boiler, It would be great if someone could give me some advice to resolve this problem, I was having problems with the boiler where I was getting the Dry-Fire warning lights on the fault finding. I’ve recently changed out the flow switch as well, When I changed the flow switch out, There was a lot of black gunk attached to the magnet on the magnet swing gate inside the flow switch. I’ve been having further problems since changing the flow switch. It worked well for the first day but today it started locking out. After firing up & working for 5 minutes, The water coming into the boiler is noisy. It was cutting out & all three lights were out on the PCB housing & the reset switch wasn’t working. For me to fire it up, I had to turn off & turn on the fuse coving the boiler on the house main fuse panel. The boiler isn’t flicking the fuse. I need to turn it on & then of myself. It fires up each time after resetting the house fuse but cuts & locks out after a few minutes. I would appreciate any advice to resolve this problem. Thank you in advance. Richy

 

[ianmcd]

sounds like a jammed/faulty pump

 

[Richard Campbell]

Thanks for the swift reply. When you say a Jammed/faulty pump. Do you mean the one located upstairs in the cupboard with the hot water cylinder? I've checked that pump & the pipes either side of the pump are hot.

 

[ianmcd]

Thanks for the swift reply. When you say a Jammed/faulty pump. Do you mean the one located upstairs in the cupboard with the hot water cylinder? I've checked that pump & the pipes either side of the pump are hot.

yes but is it actually circulating ?

 

[Richard Campbell]

For the short amount of time the boiler is running, A few radiators are getting Luke warm. The circulation doesn’t seem to be as efficient as it has in the past, Yesterday I stripped out & cleaned the pump. It was running.

 

[CBW]

Check the storage cistern in the loft for water and you may want to check the cold feed to the rads.

 

[Richard Campbell]

The F & E cistern in the loft is good & has ample water. The cold feed to the radiators is good. I've cleaned & flushed the system out with Sentinel X800 & refilled & bleed the system. No change. It's still cutting out after 3 minutes & all three lights were out on the PCB housing & the reset switch wasn’t working. For me to fire it up, I had to turn off & turn on the fuse coving the boiler on the house main fuse panel. The boiler isn’t flicking the fuse. I need to turn it on & then of myself. It fires up each time after resetting the house fuse but cuts & locks out after a few minutes.