Post by gnl on Apr 12, 2019 19:40:17 GMT -5
I have a Powermax OV157P Boiler (which I understand to be the LPG version of the 155x), operating in an open vented installation supplying domestic hot water and central heating. The boiler does not have an integrated programmer and is operated via a remote Potterton programmer and room thermostat. The boiler is around 15 years old - but it has been regularly serviced and, until very recently, it has been totally reliable.
About a fortnight ago the boiler failed to ignite and the lock-out light cut in. I checked behind the front panel and neither the limit nor the overheat thermostats appeared to have tripped. Following the User Manual guidance, I turned the operating switch off, waited a few minutes and then powered it on again to recommence the ignition cycle. On doing this, the fan started up immediately and after a few seconds I could hear the gas valve solenoid clicking into action but there appeared to be no subsequent spark at the electrode and the burner stubbornly failed to ignite. Over the next few days, I repeated this re-set procedure dozens of times - but always with the same result - the fan starts, the controller runs through the ignition cycle about 4 or 5 times over the course of a couple of minutes - and then the lock-out light comes back on.
I have been unable to find an LPG certified engineer in this area (SW Hampshire) who is familiar with Powermax Boilers so I have been working through the suggested fixes listed on this website with the help of a local Viessman trained heating engineer. To date we have done the following without be able to fix the problem :
1) Replaced the sensor tube running from the fan to the gas valve (it looked to have cracked in a few places and we thought that the valve sensor might not be picking up enough pressure to register that the fan was running correctly).
2) Replaced the ignition electrode (and gasket) and the ignition HT lead (both of which appeared to be OK - the electrode gap was correct the contacts were clean and when tested away from the boiler, the HT lead able to carry a current). While replacing the electrode, we also fitted a new gasket to the burner assembly.
3) Replaced the ignition control board.
4) Replaced the gas valve.
We are now starting to run out of ideas. There appears to be no current reaching the electrode but we are unsure if this is because there is a fail-safe circuit somewhere in the boiler that is detecting a fault and deliberately isolating the ignition electrode - or if there is a component or wiring failure in the electrical circuitry. Just about the only electrical components on the top section of the boiler that we haven't yet replaced are the capacitor (P503 - which seems to regulate just the fan ?) and the Relay P759. Could either of these be causing the ignition failure ?
By carefully shopping around I have so far managed to limit my spending on replacement parts to around £150 and although I am willing to continue exchanging potentially faulty components to try to restore the ignition, I would be very grateful for any suggestions that might point me in the direction of the underlying problem.
Thanks in advance for any help and advice that you might be able to give.
About a fortnight ago the boiler failed to ignite and the lock-out light cut in. I checked behind the front panel and neither the limit nor the overheat thermostats appeared to have tripped. Following the User Manual guidance, I turned the operating switch off, waited a few minutes and then powered it on again to recommence the ignition cycle. On doing this, the fan started up immediately and after a few seconds I could hear the gas valve solenoid clicking into action but there appeared to be no subsequent spark at the electrode and the burner stubbornly failed to ignite. Over the next few days, I repeated this re-set procedure dozens of times - but always with the same result - the fan starts, the controller runs through the ignition cycle about 4 or 5 times over the course of a couple of minutes - and then the lock-out light comes back on.
I have been unable to find an LPG certified engineer in this area (SW Hampshire) who is familiar with Powermax Boilers so I have been working through the suggested fixes listed on this website with the help of a local Viessman trained heating engineer. To date we have done the following without be able to fix the problem :
1) Replaced the sensor tube running from the fan to the gas valve (it looked to have cracked in a few places and we thought that the valve sensor might not be picking up enough pressure to register that the fan was running correctly).
2) Replaced the ignition electrode (and gasket) and the ignition HT lead (both of which appeared to be OK - the electrode gap was correct the contacts were clean and when tested away from the boiler, the HT lead able to carry a current). While replacing the electrode, we also fitted a new gasket to the burner assembly.
3) Replaced the ignition control board.
4) Replaced the gas valve.
We are now starting to run out of ideas. There appears to be no current reaching the electrode but we are unsure if this is because there is a fail-safe circuit somewhere in the boiler that is detecting a fault and deliberately isolating the ignition electrode - or if there is a component or wiring failure in the electrical circuitry. Just about the only electrical components on the top section of the boiler that we haven't yet replaced are the capacitor (P503 - which seems to regulate just the fan ?) and the Relay P759. Could either of these be causing the ignition failure ?
By carefully shopping around I have so far managed to limit my spending on replacement parts to around £150 and although I am willing to continue exchanging potentially faulty components to try to restore the ignition, I would be very grateful for any suggestions that might point me in the direction of the underlying problem.
Thanks in advance for any help and advice that you might be able to give.
