Help! Baxi boiler losing pressure

Pob_2

Hi can anyone help.
We have a Baxi Bahama 100 combi gas boiler. Recently I changed 2 radiators-drained down and replaced them, then repressurised the system. The radiators work but the boiler seems to be venting water slowly through the outside overflow pipe. Over a period of time the pressure drops in the system. Can anyone suggest a reason and possible solution PLEASE its driving me nuts. Thanks POB

Snow_Dog

Perhaps you have a bit of muck holding the vent valve from closing fully, it wouldnt take much. Is the release valve on that one a push lever? You could try depressing it fully for a second or so, if there is any crud there it may shift it.

Pob_2

Thanks Snow dog
I have twisted the valve and the venting out side seems to have slowed down to a small drip. The pressure on the combi still drops though, but over a longer peroid, any ideas?
Thanks again.

Snow_Dog

It shouldn't really be venting out normally, it could be you have a bad seal on the vent valve.

The small drip over a period will drop the pressure on the combi as you are losing water from the sealed system (you aren't overpressurising are you?).

The thing is with replacing rads and draining down you can move crud around, it may be worth having a few more goes at flushing water through the valve. If that still doesn't completely stop the water coming out the vent then you're next probable step is to drain down and strip down the valve/ or replace it.

lapat

if your pressure is dropping in your boiler you have a leak. as it says on the tin combi's are a pressurised system and they only lose water when they have a leak wether it be on your relaease valve or the pipework.

did you change any pipework when you changed the rads..?
if so check the joints as the waters hot and it will evaporate so you may not see it.
regarding the valve they are quite easy to strip down but i would suggest you buy a seal kit at least as you will struggle to reseat the seals if you nick them.
another problem could be that is your filler loop seating properley it should really be disconnected because believe it or not if your combi is upstairs and the filler loop is open i have seen a system drain back on itself when the presuure dropped in the mains outside.

hope this helps