Glowworm Fuelsaver MkII Main Burner Not Lighting

[Johnglav]

Thanks Guys for your attention on this, this isn't my area of expertise, so please bear with my inexperience.

When I re-tested the new thermostat, I found that one of the thermostat block terminals was live which was not live on the old one. So I've fitted it permenently now.

When the timer is on and the thermostat is on there is power to all of the terminals on the thermostat block. Ollski - There is power (brown terminal) of the gas valve, but no power on the blue terminal.

Chris, I cannot find any obvious by-pass pipe near the boiler. The only pipework is the large input and output pipes. More generally, only the radiators and the central heating overflow tank exit pipe have been disturbed. The motorised valve is Honeywell, the pump is Grundfos. I've opened the lever and switched on the heating, optimistically awaiting results.

Timmo, in the morning I'll clean the gas valve connections.

Thanks again,

John.

 

[Johnglav]

Chris, the boiler is a 50R MkII, GC number 41 313 79.

 

[chrishutt]

Ok, so it's not the same as the MI I was referring to, therefore ignore my information. What do you think R refers to (B referring to Balanced flue, I presume)? Could it be Room Sealed - does it have a fan powered flue?

If you've got 240 volts at live terminal on gas valve, but no gas, it looks like gas valve fault. Some Honeywell gas valves are obtainable as generic items (i.e. not specific to one model or manufacturer), therefore much cheaper than as official spare parts.

 

[Johnglav]

Ok, I believe it's fixed.

The problem was eventually tracked down to a broken overheat thermostat. It's probable that when the boiler was turned on during the flushing process, it wasn't adequately filled and triggered the cutout. I assume this is why it burned in 15 second bursts. However, after that it appears to have broken down completely. It's bypassed at the minute until a new one can be fitted.

Thanks for all your contributions. Given my aged heating system I suspect I'll be appearing regularly on this forum.

Cheers,

John.

 

[ollski]

Now I could have sworn this one had a simple thermocouple interruptor....ah well.

 

[chrishutt]

At the beginning I wrote

I would guess it might be something to do with there being air in heat exchanger and consequent cut out by over-heat stat

Not bad, eh.

 

[ollski]

Ok, I believe it's fixed.

It's bypassed at the minute until a new one can be fitted.

Thanks for all your contributions. Given my aged heating system I suspect I'll be appearing regularly on this forum.

Cheers,

John.

Big, big no no...no safety device should be bypassed, particularly an overheat stat that has recently had to operate.
John I too suspect you will be back on this forum, but I also have a strong suspicion it will be with the same problem

 

[Johnglav]

Oops, but by-passed by a Corgi man until he can fit the replacement!



John.

p.s. Well done Chris.

 

[ollski]

Oops, but by-passed by a Corgi man until he can fit the replacement!



John.

p.s. Well done Chris.

That's even worse...someone who should know better

 

[d34n0]

I was having problems every year with the pilot and main flame going out. I first thought it was the wind blowing the pilot out but later found the fix.

On the right hand side of the heat exchanger there are two censors, one mounted on top of the pipework and one that is inserted into a recess in the same pipe. After removing them and cleaning the heat sink paste on the sensor and surrounding areas then replacing with good quality heat sink paste (I used the silver stuff used on processor heat sinks) I got a good as new boiler. I also de-soldered the two wires going to the surface mounted censor and slipped a bit of insulation over the tops of the wires as they seemed to run against a sharp are of the boiler then re-soldered.
Noticed improvements:
1/ Boiler casings no longer gets hot.
2/ Main flame kicks in and out regularly, instead of on for long periods. which was a waste of gas.
Boiler does not go off for no reason.
3/ No more ketteling.
4/ I will most likely get more life from the pump and valve motors now they are not working at such a hot constant temp.

Not sure if the connection with the wind was anything to do with the heat not being able to escape the flu as efficiently as it does under normal weather and that was compounding overheating within the boiler. (Ill never know)

 

[misterdubya]

Think it may have been sorted by now. This topic is old and one of the contributors is sadly no longer with us.

Mr. W.

 

[d34n0]

I gathered that it would be but hey it stood the test of time because I used it to try to solve my problem and I'm sure others will too.
Sorry to hear about the contributor passing away