Baxi combi - pressure building

[alwest197]

Can some one give me the possible reasons for the pressure within the expansion Vessel on my Baxi 105e rising please.

I've checked the input tap to make sure it was not slowly leaking..all ok.

It takes a few days for the pressure to rise to over 3 bars, I then have to release the pressure by bleeding water from a radiator.

I should say that I fitted an extra towel rail a few months ago into what I think is the CH system pipes. Surely if I had fitted this wrongly the pressure rise would be a lot quicker than a couple of days, almost instant if you like same as filling from the input tap.

I don't suppose that this could happen through an internal boiler fault..could it..?

Al

 

[plumbnuts]

Check that the filling loop is completely closed, disconnect the flexible hose if possible.

 

[alwest197]

Thanks for this..

I actually disconnected the filling loop for a couple of days but it made no difference.

Al

 

[muggles]

Almost certainly a pinholed heat exchanger, you'll need a new one.

 

[alwest197]

Thanks..what an excellent idea... I'll get one on order.

Al

 

[muggles]

Do you know which one you need? Is your boiler a Combi 105E or a Combi Instant 105E? It makes a difference as the hex is different in either one. Also check it's an E and not a HE, or better still see if you can find the GC number which IIRC is on a white sticker on the fold-down panel. I can give you a part number, it'll make ordering easier

 

[alwest197]

Its a Baxi Combi 105e.
Fitted in Oct 2001
serial no is 01 39 062423 247902 01 00

The installation manual says the Heat Exchanger part no is 2048030

Thanks Al

 

[muggles]

Serial number doesn't help much, it's the GC number that's really needed, check it's 4707508.

Check that part number, most Baxi part numbers are six digits and you have seven there, it doesn't come up on Google either. If you've mistyped and meant 248030 that's the combustion chamber, don't order that it won't do you any good.

Assuming we're both talking about the same boiler, and I'm pretty sure we are, hex part number is 248048, the seal kit which I'd highly recommend getting as well is 248049

 

[alwest197]

hi,

I had to take the front cover off to get to the GC number its, as you say, 4707508.

the install manual qoutes the hex as 248030..

sorry for any confusion caused..

Al

 

[alwest197]

oh dear...got it wrong again...hex no is 248017...must get some glasses...

Al

 

[muggles]

Wrong again, that hex is the primary one, changing that won't sort your problem, you need the hex and seal kit I've already given you the part numbers for.

248048
248049

 

[alwest197]

Thanks for your patience...


can I take it that you mean that the exchanger which needs changing is the "plate Heat exchanger" and NOT the "Primary heat exchanger"..

The installation manual does not list a number for the plate heat exchanger..

Where is the best place to purchase from..?

Al

 

[muggles]

Yes you're correct it's the plate hex that needs changing. We get everything from Parts Centre but if you type the part numbers into Google you'll find there's places online where you can buy the hex and seal kit from

 

[alwest197]

Great

That saves a fortune over the primary one....

I'll get one on order and report back when I've completed the work...

Al

 

[muggles]

Don't forget the seal kit