Gloworm comapct 100e c/h cutout after 1 min

[ambi]

Hi all,
Looking for some pointers?
Daughter has decided to try heating after months of just D/h/w. Start up procedures appear to go all o.k. with no lock outs and boiler fires up but only for 1 min and then cuts off!
D/h/w call has been mediocre for months( luke warm ). Whilst c/h was on it ( D/h/w)was very good. Following this 1 min cut off D/h/w is very hot ( assuming due to C/h call ) and then fades to luke warm. Diverter switch/valve was pencilled in for a replace to cure this problem. Pump appears to be working due to noise change via selector, but pump is very hot after the 1 min and water is very hot from bleed screw when opened.
Could the diverter valve had moved and stuck with no heating being used, or does it rest at C/h demand normally? Would the hot water around the pump not have dissipated if it was working o.k.? May it be the C/h overheat stat?
Best way forward from the experts would be appreciated.
Cheers

 

[ambi]

It`s been 37 mins guys and no ponters?

 

[twgas]

are all, or at least one, rads turned on - both ends

 

[ambi]

Yes they are Mick, It was working fine before warm weather came...........but I have just thought....maybe an air lock has occured due to staticness over summer with subsequent C/h call moving it through system. Thoughts?
I shall make that the first port of call when I get down there!

 

[twgas]

when you get there double check the rads are on, also check the iso valves on boiler. make sure the system pressure is good 1 to 1.5 bar.

 

[ambi]

All that I do know is as was when last working. I am there a lot. Do you think just a settlement of air could possibly cause this?

 

[ambi]

System and pump bled earlier, problem persists? Suggestions welcome!

 

[twgas]

does the boiler go to lock-out (reset required) or just shut down on temp control.

 

[ambi]

does not go to lockout and does not require a reset. It just shuts down after about 1 min of burner operation and then does the same again eventually after it has cooled down.

 

[ambi]

It is very hot around the pump area though!

 

[twgas]

I beginning to suspect the pump is partially bocked, preventing it pumping properly so causing the boiler to get hot so quick - and not cooling down for some time.

 

[ambi]

It does sound a possibility Mick. Maybe I`ve been kidded by the pump noise change when the speed adjuster is changed! Nex visit = Pump bleed screw off and try and see if impeller can be spun with screwdriver!

 

[twgas]

you will only be able to spin the shaft, the impellor should spin with it but it is possible for the impellor to become detatched. a better option might be to drain boiler, split pump, clean and refit or replace.

 

[ambi]

Yeh Thanks I`ll play that one by ear. i.e. see if it feels tight at first. I`ll report back with results when been back there.

 

[ambi]

Back to this one guys?
I would appreciate the experts opinion with regards the following

Fault persists. Pump is working o.k. Boiler still shuts down after 1 min when C/H selected with an increased water temp from D/H/W for a short time afterwards ( assuming the small C/H fire up is causing this ) Following this the D/H/W is normal temp again with no boiler shutdown happening on D/H/W and running o.k. Problem only on C/H selection.
I have removed the electrical diverter switch as per fault finding and observed the enclosed pin moving in and out on c/h & d/h/w selection as it should do.
I have tried to manually press the brass spindle in the diverter valve as per the fault finding to simulate c/h and d/w/h selection to see if it operates? I can only feel about 1/8 of an inch protruding out which is impossible to manually depress anymore! I am assuming that the diverter valve needle/pin has maybe siezed/broken and appears to be locked in the d/w/h position, which I am guessing well may be the problem overall?



The price being quoted for a replacement diverter valve/needle seems quite steep!

Has anyone encompassed this problem before?
From the diagram there does not appear to be much in the valve which makes me think it may be possible to remove and free off if stuck?


Opinions and thoughts are most welcome?
Regards