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dhgas
The story so far
Got call to hotel with 2 x promax's, neither one firing. Restricting air intakes allowed both to fire. On checking inlet pressure found to be below MI min, so checked at meter and found 17mb, so got the pressure adjusted. Both boilers the fired ok.
After couple of days got call that right hand boiler keeps locking out and there is not much heat to building (which I put down to only 1 boiler working). The lock out was caused by boiler not lighting, gas valve opened, fan run, spark worked but no light. Restricting air intake as before allowed boiler to fire. Gas valve thought I so tried potterton technical and they agreed. New gas valve later and boiler still does not fire (except with hand restricting air intake).
When boilers were going I checked the CO2 level, it was 8% MI say 9%+_1%, so within spec. MI also say DO NOT ADJUST GAS VALVE.
After much umming & ahing I decided to try adjusting the gas valve, on principal I could always put back again. As soon as i adjusted the valve the boiler fired, so I adjusted to 9% CO2. The fault of lockout then transfered itself to the other boiler. I thought in for a penny.... And adjusted the second boiler to 9%.
I still got not enough heat complaint but still put this down to only 1 boiler working.
Both boilers now do not lock out, still no heat complaint. Finally gas rated them. With both firing the gas rate is about 21Kw. Back onto Potterton who said either fan or PCB (which I had already thought myself). 1 PCB & 1 fan later and boilers are no different.
Back onto Potterton tech, could be wrong wiring loom they said, as this decides which boiler it is. 1 new wiring loom later and still the same.
Am now wondering what else to try. Am wondering if a fault with fan or board may cause both to fault and would it be worth trying new fan & board as single unit??
I feel the fault is with the fan speed as that is what determines the final gas usage. According to Potterton there is no way to check the fan speed.
Anyone any thoughts????
Got call to hotel with 2 x promax's, neither one firing. Restricting air intakes allowed both to fire. On checking inlet pressure found to be below MI min, so checked at meter and found 17mb, so got the pressure adjusted. Both boilers the fired ok.
After couple of days got call that right hand boiler keeps locking out and there is not much heat to building (which I put down to only 1 boiler working). The lock out was caused by boiler not lighting, gas valve opened, fan run, spark worked but no light. Restricting air intake as before allowed boiler to fire. Gas valve thought I so tried potterton technical and they agreed. New gas valve later and boiler still does not fire (except with hand restricting air intake).
When boilers were going I checked the CO2 level, it was 8% MI say 9%+_1%, so within spec. MI also say DO NOT ADJUST GAS VALVE.
After much umming & ahing I decided to try adjusting the gas valve, on principal I could always put back again. As soon as i adjusted the valve the boiler fired, so I adjusted to 9% CO2. The fault of lockout then transfered itself to the other boiler. I thought in for a penny.... And adjusted the second boiler to 9%.
I still got not enough heat complaint but still put this down to only 1 boiler working.
Both boilers now do not lock out, still no heat complaint. Finally gas rated them. With both firing the gas rate is about 21Kw. Back onto Potterton who said either fan or PCB (which I had already thought myself). 1 PCB & 1 fan later and boilers are no different.
Back onto Potterton tech, could be wrong wiring loom they said, as this decides which boiler it is. 1 new wiring loom later and still the same.
Am now wondering what else to try. Am wondering if a fault with fan or board may cause both to fault and would it be worth trying new fan & board as single unit??
I feel the fault is with the fan speed as that is what determines the final gas usage. According to Potterton there is no way to check the fan speed.
Anyone any thoughts????
