Myson Apollo Fanfare 40Si boiler problems

Philby54 · 22 Oct 2008

My boiler has just started to play up the the problem is that the burner lights up ok runs for 5-10 mins then stops, and will not re-light up for anything from 15-30mins although the spark electrode is sparking away.
I have checked the hi, lo, and overheat thermostats and all ok. The pump is running ok. I have checked the voltage across the main gas solenoid whilst the boiler is running and getting 240volts until whatever the problem is causes the voltage to drop to zero & turn the gas off. A friend said it will be the thermocouple but there is not one fitted on this boiler, unless it is done through the spark electrode/flame sensor. Help please

malkie · 22 Oct 2008

Hello is it getting heat to the rads before it cuts out now if its reaching temp then trying to fire back up i can see maybe a pcb fault,see your boiler is telling the fan to run which allows the aps to open causing the ignition to start but when its sparking you say theres no 240 at the gas v alve which tells me its the pcb

namsag · 22 Oct 2008

Areyou sure the voltage on solenoid is dropping to zero or just assuming it is because the gas is going off , does it have 2 solenoids . Pilot and main gas

giblets · 22 Oct 2008

Does the fan ramp up to full speed on a call for heat?

Philby54 · 22 Oct 2008

The fan is definetly ramping up & running at full speed this part is relatively new as the originial motor packed up a few years back. As far as voltage on the main solenoid goes, It definetly drops to zero volts, I have a digital volt meter connected to the terminals and the reading while running is 240v dropping to zero as the flame goes out.
There is 2 solenoid valves, pilot & main. I have only checked the voltage on the main solenoid so far.

The rads barely get warm as it cuts out after running for only approx 3-4 minutes before it cuts out. ( got less time since original post)
Immediatly the flame goes out the spark electrode starts to spark again, but will not re-ignite as there is no voltage to open solenoid for at least it would appear now, an hour.
I have checked the 2 relays on the ignition board they are both working correctly which energise the solenoids

namsag · 22 Oct 2008

Well if the pilot drops out , Then you would not get any voltage to main solenoid as pilot needs to send signal back to board to then allow power to main solenoid.

I would suspect your pilot solenoid is shot and breaking down under use.
So as its sparking away check the PILOT solenoid for 240 if its getting 240 then new pilot solenoid req if its not you should be looking at pcb

Philby54 · 22 Oct 2008

namsag said:
Well if the pilot drops out , Then you would not get any voltage to main solenoid as pilot needs to send signal back to board to then allow power to main solenoid.

I would suspect your pilot solenoid is shot and breaking down under use.
So as its sparking away check the PILOT solenoid for 240 if its getting 240 then new pilot solenoid req if its not you should be looking at pcb

Thanks I will check that asap.

Philby54 · 22 Oct 2008

Right I have checked the voltage across the pilot solenoid terminals ang getting a reading of 240v as the system is fired up to the call for heat. the pilot & main burner light up ok, as the pilot & main burner go out there is still 240v across pilot solenoid terminals but no gas flow to the pilot burner.
I think you may have the answer Namsag in that the pilot solenoid is nackered ,my next problem will be getting a new one thanks for your help.
Am I right in thinking that if the pilot (input) solenoid is not opening then gas cannot flow to the main solenoid?

namsag · 23 Oct 2008

Yep thats right , is pilot solenoid little black or red cylinder shaped thing about an inch long.
If so have a look on honeywell site or on mjt controls (for part number ollski had a link to honeywell site he may put it if he sees this post) cost approx 20 quid no need to touch gas as it is held in place with a push in clip and just slides onto the shaft.

Edit.
here is part number for mjt controls 45900406-003 that is for red solenoid which will do same job as black one cost under £12

Philby54 · 24 Oct 2008

Got the new solenoid coil (red) this morning cost £18.00 inc vat, fitted it and the boiler is running like new again.

Thanks again Namsag

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Myson Apollo Fanfare 40Si boiler problems

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