My combination boiler leaks. It's only a drip, but still a couple of ltes a day

It's a Vaillant unit, either a
VCW GB 242 EH
or a
VCW GB 282 EH

Having taken the side panal of, andlookng at the instructions that came with it it appears to be leaking from the
DHW Heat Exchanger, also called the Secondary Heat Exchanger.
Part No. 06-1834
G.C.No. 255 247

Having done a quick search i found the part here:
http://www.mjtcontrols.co.uk/Part_Type3.aspx?Manufacture_ID=52&Part_Type=HEAT+EXCHANGER
however it is £100 (inc Vat).
anybody know anywhere cheaper to get it from?

ALso, from the manual it looks pretty straight forward to replace: turn of ll the valves gas water leccy.
remove the covers, drain water from boiler inc CH, undo pipes and swap.

anything i am likely to trip up on?

Is it the original plastic SILO type heat exchanger?
Is it dripping around the joints between the top, bottom & middle sections?
If yes & there isn't too much scale on it try tightening the screws/nuts & bolts up gently (so you dont damage the the plastic). Otherwise the replacement is a full kit to convert it from plastic to s/s plate type heat exchanger and requires the fitting of new pipes & the new h/e all contained in the conversion kit. Vaillant aren't the cheapest for parts so keep searching around for a deal! Theres loads of spares suppliers out there & most will mail order.

The boiler is about 15 yeas old, and was serviced annually up to 2 1/2 years ago - I have been moved in for 2 months.

It looks like 3 vertical black plastic tubes joined together, with some white scum in places ~ around the joints.

Seem to be dripping from a little hole (purpose bulit?) near the top. If I put my finger over it, the presure builds up, and can actually squirt a few inches

tried tightnening the screws, didn't do much at all

Cheers

Sounds pretty terminal for the heat exchanger then!
They changed away from those plastic ones due to their tendancy to crack & breakdown with age.
Thats mains water pressure inside there so i'd recomend chasing around a few spares stockists for the best deal tomorrow morning before it lets go properly!

is this what i need?

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=6017065286&fromMakeTrack=true

Aye that be the beast !

Well have replaced the DHW Heat Excahanger with a new stainles steel one, however I cant seem to get the boiler to fire up!

No have no heating and no hot water!

Have tried bleeding radiators, but reckon have probably put even more air into Central heating system!

any suggestions most welcome!

[Edited on 11/12/05 by Lawnmower]

Try fully bleeding the system/rads then try venting the pump (big silver screw on front), itend to run these at about 1.5 bar.
Does the pump run up? Can you hear it? Under the silver cap you can test the spindle with a screw driver to see if it's spinning, if its not you can spin it up from the same place. Does it try to light or does it do nothing at all?

Hi, fixed it the other night, thanks for your help.

STupidly, I hadn't refilled the CH with water after i swapped parts,. thus boiler was empty and a failsafe must have prevented it from lighting.

All fixed now, touch wood!

cost me £85 over all, (plus whatever it cost me in leccy to heat the house for two days with portable electric fires!)

thanks again!