Ideal Classic HE 18 query/problem.

[carlbyrne]

I had this boiler fitted a few weeks ago. All was fine until I noticed by chance when I was washing early one morning that when the boiler starts up in the morning you can hear it sparking for upto 15 times before the pilot lighte and then the main burner. For the rest of the day it lights first time. I queried the installer who came back and checked the pressures - 26mbar at boiler when boiler off, 20.6 mbar at boiler when riunning, and the main burner pressure was 12.9 mbar (stated in manual as 12.7 mbar). He called Ideal and they agreed to change the main gas valve - it made no difference.

Trawling the internet I found reference to a sticking gas meter regulator valave diaphram as a possible cause. This morning I turned on the gas burners of the cooker (as suggested) prior to switching the boiler on - it made no difference - there being 9 audible clicks form the spark generator before the boiler lit.

I checked the voltage on the pilot light solenoid - 240 volts immediately prior to the first spark. Oddly this solenoid remains at 240 volts even after the main burner has lit - is this correct? I would have thought that the solenoid would have been deenergised once the boiler had lit.

Any suggestions? Is it indeed a fault? Should I forget it and not worry?

Cheers Carl.

 

[gas4you]

I would want to check the pilot injector and position of the spark electrode.

I would also drop the pcb casing and gently tap the relays on the board when it is sparking, to see if this made it light quicker, pointing to a sticking relay.

What happens if it has been off all day and tries to light for the first time in th afternoon for example?

 

[carlbyrne]

Dave - thanks for the reply. I think it unlikey that it is the solenoids as the gas valve complete has already been changed with no effect.

The gas fitter has ordered a new electrode just in case it is playing up - he said it was highly unlikely but something else to rule out. Ideal seem to be at a loss as to what else it could be.

The boiler has been off all day today. Before I turned it on I disconnected the main gas valve wires so that the main burner wouldn't fire up. I then turned on the boiler and looked through the window. It took five sparks before the pilot lit and when it did it was a blue flame just over an 1" long. However, it was fluttering a little like a 'candle in the wind' - almost like it was too drafty for it. It got me wondering if the fan is naturally drawing the pilot gas vertically and possibly out of the line of the electrode/spark. Daft so it sounds I wonder if there is something odd about the shape of the deflector. How is the position of the electrode adjusted?

I am intrigued by the cause of the fault. Hopefully he will be back tomorrow with the new electrode.

Cheers Carl.

 

[carlbyrne]

Dave - I just reread your message. I had confused your comment about the relays, taking it to mean solenoids - hence my comment regarding the gas valve. That said, from previous tests the pilot solenoid has 240 volts on it after the fan turns on and prior to the first spark so surely it should light. Is there something we are missing here?

Cheers Carl.

 

[gas4you]

Shot in the dark, check case and flue seals if the pilot is flickering.

I would still want to blow through the pilot injector with my compressor though.

 

[carlbyrne]

Well the installer has been back and several more tests carried out.

With front cover off, main burner solenoid electrically isolated, fan disconnected, and a small positive pressure applied to the RED pipe to the pressure switch (to simulate the fan is running) the following has been deduced at start up.

Excellent spark.

Gas can be heard coming from the pilot light jet.

However, after the boiler has been off overnight it takes upto 15 seconds for the pilot light to light despite repeated sparks.

We (Corgi installer, and me the sparkie) have concluded there are now ONLY two possibilities:

1. The gas initially coming through the pilot light jet is not volatile. The boiler has only run for about three days since installing - surely enough time to purge out any air from the system? Following installation the system was properly purged anyway. The boiler is connected by 22mm pipe to the meter - about 6 m of pipe. We don't see how it can be an oxygen problem as for the above tests the cover of the boiler was off, the boiler had not been run for 12 hours, and the room was well ventilated. Since the boiler is plumped at the highest point of the gas system could it really be that any impurities in the gas are settling at the highest point overnight? It seems excessive impurity (typically carbon dioxide) if this is the case.

2. The initial flowrate of gas from the pilot light jet is too high. This isn't adjustable so what could cause this, if this is actually the case? When lit, the flame is blue and about 1" long as specified by the manufacturer. The gas coming from the pilot light jet is audible with the boiler cover off.

The gas valve has already been replaced once with no positive effect.

Static and dynamic pressure are consistently ok - see above.

Another check made - with the manometer connected to the inlet point of the boiler solenoid gas valve the gas cock on the boiler was shut off. Initially there was 260 mm of water reducing to about 130 mm after 5 hours. This seemed to be a trivial leakage from the boiler valve itself?

Could it be possible that the gas supply is contaminated with more than the normal amount of impurity? We have checked with the immediate neighbours who have had no problems BUT they have old boilers with permanent pilot lights. This is not a rural property but one situated in a built-up area.

Any suggestions please???

Cheers Carl.

 

[gas4you]

I don't know why the fan has been disconnected etc If the boiler is sparking then the fan and aps have been proved and all is ok this far.

If the spark is good and in the correct position, then it has to be the gas valve or pcb.

Have you tested for the required voltage at the gas valve solenoid terminals on the board?

Have you tried tapping the relays as I previously suggested?

 

[carlbyrne]

Thanks again for your help.

The fan was disconnected merely to cut out its noise so that we could hear if gas was coming from the pilot jet. Bear in mind that the main burner valve was also electrically isolated so that the burner could not fire up.

I don't see how it can be a PCB fault bearing in mind that there is an excellent spark AND 'gas' can be heard coming from the pilot jet. Nevertheless, we did try tapping the PCB/relays and it made no difference. A new board is also being sent down purely to rule it out - I don't think that it will change anything.

The voltage at the pilot light solenod is 241 volts when last checked.

Andrew plans to use his gas detector to check whether a combustable gas comes from the pilot jet during the first 10-15 seconds prior to lite up.

The electrode has been position as stated - 3-5 mm. If this was however incorrect would it not affect every time the boiler lites up, not merely the first time each day?

Cheers Carl.

 

[gas4you]

How could you hear if gas was coming out of the pilot jet without the fan connected?

The pilot solenoid shouldn't be live until the aps has proved the fan

Have you checked the ignition lead fully for arcing?

 

[carlbyrne]

Dave

As said previously, a small positive pressure was applied to the pressure switch pipe so that the switch triggered and the pcb thought the fan was running thereby initiating the sparking. We have basically fooled the aps into thinking the fan is running - otherwise we wouldn't get the pilot solenoid energised and sparking. Or are we missing something here?

There is definitely no arcing along the cable although I have heard of this happening with another similar boiler when the pressure switch wires were laying against the HT connector on the PCB - ity seems bad design that soldered tab on the PCB is not completely insulated when the electrode connector is fully connected. I can guarantee that the spark is strong, reliable and where it should be.

This has pricked up both (Andrew and I) our curiosities and we would really like to find the true specific cause rather than simply cure it by random part replacements. Luckily it is my boiler and I can live with it not working at present - not for much longer though!

Cheers Carl.

 

[gas4you]

Well, you know what Ideal technical would say?

Installation fault or spiders webs

Have all the above tests/checks you have detailed been done when the boiler won't fire, or just when the engineer can be there?

 

[bigtank78]

I would want to check the pilot injector and position of the spark electrode.

I would also drop the pcb casing and gently tap the relays on the board when it is sparking, to see if this made it light quicker, pointing to a sticking relay.

What happens if it has been off all day and tries to light for the first time in th afternoon for example?

gas4you (or whomever else may be able to help)

I have had an intermittent fault with my Ideal Classic FF340 for a few weeks now. An electrician found the fault to be with one of the relays on the board. It seemed like applying pressure, instead of tapping it, caused the boiler to fire. Am I right in thinking this may be a faulty solder joint as opposed to a sticking relay?

The PCB is over £100 to replace (part only I still have to add vat and fitting) Is this something that could be repaired? Could the joint be soldered? Would it be possible to replace the relay if it was faulty?

Cheers

 

[shambolic]

Had a similar problem ona site mate with 6 boilers and it was actually the main gas supply to the site had never been purged properly by NAtional grid/transco whatever they are called now.
This led to an improper air gas mixture causing boilers to fail to light properly.

We ended up clearing site for 30 mins while purging supply from furthest away meters and all legs.
But TBH honest first thing in the morning you could have a we bit of condensation on the probes or in the pilot injector.
If its sparking a few extra times whats the problem its lighting isnt it??
Classics are more or less bulletproof and occasional fan or main pcb.
As this is a new instal it sounds more likle the above gas problem.
Also check earth and neutral to earth as bad neutral can cause problems rectifying the flame!

 

[carlbyrne]

Many thanks for the suggestion -- the problem still persists even after the gas valve and board has been changed!!

Assume that the boiler is left OFF over night. If the pilot solenoid is separately energised with a mains supply for about 15 seconds (to purge the gas valve). Then the solenoid is reconnected to the PCB and the boiler is switched on, the pilot lites and the boiler fires up within about two sparks.

The question is - how is the 'gas' in the valve being contaminated overnight?? It seems like the gas valve has to purge itself which takes upto twenty sparks. Surely this isn't right?? Ideal and the Installer seem to be happy so I have to accept it. Surely the poor old spark generator will wear out prematurely? I have already bought a replacement 25E board ready for that day!!

Cheers Carl.

 

[carlbyrne]

Any ideas - any one???

Cheers Carl.