VCW 242

[John2512_00]

Hi all,

Was trying to sort out a freinds heating system today, shes just moved into an older house. VCW 242 boiler running 6 rads.

They were getting various probs, (lots of leaks on the rads) so sorted up as much as I could.

After having drined the system/relived pressure more like, to repair the leaks on the rads, i filled the system back up to 1.5bar and ran the boiler.

Could hear it sparking then going to lock out without lighting.

After a little mucking about I discovered that if i knocked the black plastic section on front of the gas valve while it was sparking the flame would appear.

And a little later if i hit that part again it will go to high flame.


Im not too familair with these boilers as Im guilty of running away from them in the past when i see it working for more than 10 sec lol.


But I want to learn now, would a typical thought be that the venturi/tiny copper tipes from the pump to the plastic unit are possible blocked?

is there a diaghram inside that black section or something i can strip and clean to make it modulate/control the gas valve better.

Thanks Very much for any input possible.

 

[Agile]

Thats really just an interlock but it is slightly proportional if its moving fully. Probably should be CORGi registered to work on it.

The pump may not be pushing hard enough, there may be a blockage or the capillary tube may be rather blocked at the pump end.

The diaphragm rarely fails but is normally replaced as a whole unit.

Tony

 

[John2512_00]

Cool cool, ill have a look at the pipes from the pump, as far as I can tell the pumps ok, but not tested it properly yet.

I think this has only started happening since I drained it down and I did get a shot of sludge in the face from one of the rad pipes after realising there was a blockage in it, so wouldnt be surprised if iv cuased some sludge to travell into those pipes when drainning/filling.

I am corgi registered (not that you could tell lol) But only been for maybe 8 months and only had to work on like 2 or 3 of these before. So guess Ill be going back to clean out those pipes.

Wasnt sure if there was a common prob with the diaghrams in them but thanks for clearing that part up.

Hate it when u fix one thing and aother causes problems folk jus think uv broken the boiler lol.

 

[Agile]

Now you are starting to tell the whole story!

If you have disturbed sludge it make it almost certain that some debris has got into the flow interlock or pump impeller.

FIRST remove the pump head and see if there is dirt in the impeller. If not then do a finger test to check the torque.

If you want to risk detaching the two capillary pipes from the switch you could see if water flows freely from them but be warned they leak unless carefully cleaned and greased.

Tony