apollo fanfare banging then pilot light out

[ndmxp07]

looking for help with a myson apollo fanfare 30/50s. when the boiler lights there's lots of banging and it sounds as if theres air in the pipes, (this happens for HW and CH) then after 30 seconds to a minute the boiler shuts down and the pilot light goes out.

On the rare occasion that the boiler will stay lit for any length of time it will fire for half a minute then stop then fire again then stop and so on until the banging starts.

So far i have drained and refilled the system, flushed the heat exchanger and changed the pump. the motorised valve synchro motor and thermo-couple are less than six months old.

any help much appreciated, many thanks

 

[namsag]

If you have changed pump and wired in correctly and removed all air locks , when you turn boiler on at first check for 240v at pump if there is no voltage ,the highest probability is it is your pump over run stat that has gone(this is where the pump gets it`s power from). This is fitted inside the boiler at the bottom right handside about the size of a ten pence coin and held to boiler chasis with two self taping screws. Cost about £20 .The loud banging is the water getting far too hot by staying in the boiler too long either by air lock or pump not spinning.

 

[ndmxp07]

thanks for that i will check asap

 

[ndmxp07]

checked for voltage at pump have constant 240v, pump definatly working. any other suggestions?

 

[AlanE]

Pump has 240 Volts but is it actually pumping?

Alan

 

[ndmxp07]

pump is definately running but how can i tell if its pumping? when i remove the centre screw its spinning and i get a constant drible of water. it makes sense that the problem here is water not moving from boiler quick enough, but why, i've already changed the pump. could it be a blockage between boiler and pump? if so what can i do? thanks for your help

 

[namsag]

Have you fitted pump the correct way round and live and neutral to correct terminals(does happen,not being condesending), even though pump valve spindles may have turned have both the actual pump valves opened, have you bled every available air release and got water out check around cylinder for hidden ones. If it`s air turn boiler stat off so there is no banging turn just HW on so the pump is working and use speed selector on side of pump to try different speeds to shift air also remove bleed screw from pump ocasionally to let air out, then leave running for half hour to see if anything shifts. Other than that get someone in.

 

[fuelmonster]

Sounds like its the gas valve, banging noise is the solonoid trying to open? See if you have 240 volts at the gas valve after its gone through all the fan start etc.

 

[ArtfulBodger]

Sounds like its the gas valve, banging noise is the solonoid trying to open? See if you have 240 volts at the gas valve after its gone through all the fan start etc.

I've never heard a gas valve banging, clicking yes .......

 

[kevplumb]

they only go BANG once