Glow worm compact 100e - DHW probs / part no advice plse

[beefster]

Hi,
Had a similar problem before which was down to the Plate heat exchanger being partially blocked. On DHW mode water goes hot/cold/hot/cold (and trips now and then) as burner goes on and off. I assume on the primary stat temp control?? On shut off of DHW some kettleing can be heard and occasionally trips.

When opening the boiler to take a look, scale and a slight leak around the DHW micro switch.... changed the sw last year.. no leak then. I have the part no for the diaphragm 801191, but should i replace the brass housing / gland too?? and if so what part number is it... i cant find it on the net??

Also not 100% sure the burner is modulating.... on DHW it just seems to go on and off at the moment..... was thinking the plate heat exchanger and poss dhw switch prob may be causing that some how??

All help most welcome.
Ta all.

 

[beefster]

Anyone????????

 

[Gasguru]

Change the DHW diaphragm and brass cover plate assembly. Check the microswitch..they are often full of water. Use the existing screws. Search previous postings for part numbers..I must have posted them several times.

Turn the hot water temperature control down gradually and see if the burner modulates at different settings. If it does it's a good indication the plates clogged. The primary thermister is in effect used as an overheat stat in DHW mode. Therefore any slight overheating due to poor heat transfer across the plate will just cut the burner off rather than modulating down early as with most combis/blocked plates. A miniscule amount of debris will cause problems. The plates are a crazy price on the 100s.

These boilers often run at too higher burner pressure..the design is carp so gas ratie it (see FAQs) to be sure (providing boiler doesn't cut out early).

 

[beefster]

Thanks for that...
Did a quick search before but didnt see the part numbers.... if i cant find i will call Glow worm on monday?? Will go further back in the searches....
Put some flushing agent in the system this week and its helped a bit... just moved the muck probably!

What about recon heat exchangers?? I've seen a few for sale at £40 ish?? Worth a punt.... mines a pig to get out as i have the top feed conversion kit which means it cant come out unless the conversion kit pipes are also removed!! They run tight behind the P H Exch.... Total pain.

Will check the modulation out... ta for the info.

 

[beefster]

What a pain of a job..
Removed the conversion kit pipework for top connection, but the p heat exchanger wouldnt come out. Had to take the whole pump assembly and block out as there had unknown to me been a slight leak there and the heat exchanger was well and truly stuck to the block...

Long and short of it is changed exchanger and DHW demand switch housing. Flushed the system and its spot on now.... )

 

[ecoangel]

Seem to have similar trouble with mine.

Twas installed in late 2000 and had proper servicing and inhibitor.

Leak appears to be coming from behind the DHW microswitch.

Also Hot water from tap is poor at higher domestic pressure flow rates. Have to wind tap to near minimum to run a HOT bath.

Any ideas? Part numbers and recommended suppliers.

Many thanks

 

[ecoangel]

what is the brass housing part number?

Can the heat exchanger plate be cleaned out?