Glow Worm Ultimate 50BF

[Teggs]

Hello Everyone.

I am having problems with my central heating and hot water, my Glow Wom Boiler does not seem to want to stay lit for more then a minute or so. My system is as follows:

Glow Worm Ultimate 50BF boiler
Danfoss 103 time switch
Honeywell roomstat
Honeywell cylinder stat
Grundfos pump

I have tested all the external components and find that these are working fine. The pilot is on in the boiler, but when I set the timer to constant it doesn't kick in. On the rare occassions that it does the boiler only remains working for about 5 mins - if that.

I can see from other posts on here that the pilot injector and/or main burner may be to blame. I have opened the boiler and lightly cleaned, using air, both of these components. After doing so I thought this had fixed the problem, however after 10 minutes it stopped again only leaving the pilot light on.

Can any of you suggest anything else it might be, and if not is it possible that blow cleaning these items might not have done the job? If new components are needed I'll call a gas engineer, but having some understanding of the problem would be great.

Terry

 

[namsag]

Check there is enough water in the syustem ,check ball valve has not stuck in header tank

 

[Teggs]

Hey thanks for the sppedy response.

I have checked the header tank, it has sufficent water in their. Also bled the pump and checked rads for air, all seems fine?

The 3 port valve appears to work without issue as well.

Terry

 

[gas4you]

Could be the gas valve is dropping out. You need to see if there is 230V present at it when it goes off.

 

[Teggs]

Hey guys,

Apologies for the delay in replying to the last post. Been away to the Highlands (great open fire), came home to my cold house.

I tested the voltage to the gas valve and this remained at 240 when the valve clicked off (continuing to do so). After about 10 minutes or so the boiler relights but again remains lit for only 5 minutes or less.

Does this imply that this valve is to blame? My other thought was that it might be the thermostat on the upperright hand side.

Any answers would be greatly accepted, if it's the gas valve I'll not touch it for the obvious reasons. Finally is it worth fixing the boiler in this instance?

Teggs

 

[Teggs]

Gas4You,

Can you describe to me what you mean by a gas valve dropping out? The voltage to the valve remains at 240V when the boiler turns itself off. At this stage the pilot remains lit.

If you require any further information let me know

Terry

 

[namsag]

If you have pilot on and 240 to gas valve connections and no main flame it is a faulty solenoid on gas valve

 

[Rob]

Are you checking both solenoids? Im assuming it has a pilot and main. Make sure its 240v to the main your getting.

Could be an electronic fault if not.

Dont know these that well.

 

[namsag]

Permenant pilot on the BF rob so only one solenoid

 

[Teggs]

Cheers Guys,

Is the solenoid available as an individual item or will the engineer have to replace the whole gas valve?

Terry

 

[Meldrew's mate]

Hate to be a spoilsport, but I think you have mis-measured the solenoid voltage on the gas valve. If you had 240v on the coil and the main burner is off, then what turns it ON when it does come on????

I read you've checked all the external components. Does the pump pump? i.e can you hear water surging when you change speeds? It's not unknown for the impellor shaft to shear so the motor turns but the pump.....doesn't pump!

Suggest you feel the exit pipes at the boiler, if they get very hot before the burner shuts-off then it's a lack of circulation problem. If they don't then suspect the boiler-stat MAY be faulty.

MM

 

[namsag]

Eh if he is getting 240v at solenoid if it is not turning it on then it is a faulty solenoid not lifting the gas valve/or a faulty valve .

If he is getting 240v at solenoid(and its not firing) it can`t be the thermostat or any other external control

But as solenoid for these are only a tenner it`s best to change that and 90% of time that is what it is

Your solenoid i take it is round about inch and half long (probably black)

www.mjtcontrols.co.uk honeywell part number 45900406-003 red solenoid 240v £10.50

 

[Meldrew's mate]

Man of gas, normally I'd agree with you, and your last post makes perfect sense, but add the following comment:-

...I tested the voltage to the gas valve and this remained at 240 when the valve clicked off (continuing to do so). After about 10 minutes or so the boiler relights but again remains lit for only 5 minutes or less...

and you can see where the inconsistency lies. This is too regular to be a "stuck" gas valve or a broken winding on the solenoid (which regularly repairs itself), which is why I questioned the information supplied. It's more likely to be a lack of circulationcausing this symptom.

So I repeat my advice to the OP, do the boiler pipes get very hot when the boiler goes off? I have known pump impellor shafts to shear, the little rubber ball in the Honeywell 3-port valve to fall off and regularly block the heating port, but never come across an intermittant solenoid coil fault -they either work or they don't.

MM

 

[namsag]

Had at least a hundred intermittent solenoid faults over the years. Which is why i`m believing him when he says continuous 240v , If he isn`t gettin continuous 240v then yes would be thinking along your lines

 

[ChrisR]

Teggs how are you measuring the 240V?
If you measure between one (live side) and earth or neutral you could be fooled by something like a thermostat switching in the other connection.

Yes they do go intermittent!
Measure the coil's resistance when it's cold. Couple of thousand ohms or of that order. Then run the boiler, and as soon at it drops out, isaolate the leccy and measure it again. If it's open circuit you found it.