Greenstar boiler problems 😣

Gemlg

I am at my wits end with our boiler-
The pressure is dropping up to 3-4 times a day. We have renewed the prv and the expansion vessel but the pressure still dropped within a few hours.
Any ideas ????
No sign of water leaking anywhere in the house from radiators etc.
Only possible sign of water running away is through the white pipe in the wall into our drains outside (not the copper pipe).

Heating engineer coming back but also at wits end of answers. Next to change the heat exchanger!?! But more expense and what if it isn't that???

Any help/advise will be much appreciated

Seronera

Well he's done all the things i'd have done. To test if its the heat exchanger there are two ways. One is to just route the condensate into a bucket, repressurise the system then see if the bucket fills up with the boiler switched off. With the boiler off NO condensate will be produced by the boiler so any water has to come from elsewhere.

The other way to test for heat exchanger failure is to repressurise the boiler then turn off the boiler isolators on the flow and return pipes. Leave it overnight switched off and if by morning (or earlier) the pressure has gone, then its the heat exchanger.

Just a warning...make sure he checks the plate to plate direct hot water heat exchanger as well. That could do the same.

How old is the boiler? Worcester Bosch may provide support if its relatively new, but you need to find out why it has failed to prevent it happening again. The usual reason is corrosion caused by dirty system water that is uninhibited. I've seen a Worcester Bosch Junior heat exchanger corrode through in 3 years due to dirty system water full of ferric sludge

Gemlg

Thank you very much, this has helped
I shall let you know how we get on. We have just had an extension with new radiators and the system drained a few times etc so it's probably not helped matters.
The boiler is 11-12yrs old, we've been in the house 8.5 of that with no problems whatsoever until now. Worcester won't offer a monthly cover due to age of the boiler but will come out for a charge of £262.50 all in apart from certain parts ie the expansion vessel and heat exchanger, typically!!

Seronera

A new Heat Ex is about £380 plus fitting, but if you look on ebay there are some at £160 upwards. If you are sure you can get the right part number for your boiler it makes it worth repairing if you can keep the parts price down. Otherwise repairing it will be a close run thing to swapping it for a new boiler with a long guarantee (subject to servicing annually).

Some will say its aluminium alloy heat exchangers you should avoid. Well the alloy one on my Ideal is 23 years old and still has some life in it, so properly protected with inhibitor they should last.

10+years is a difficult age for modern boilers though. Most are repairable, but the question is whether its economic to do so in the light of the low cost of new boilers (they are a lot cheaper than they used to be...in every way)