circulating pump aav

[coldwrench]

Leaks were causing my heating system to loose nearly 1bar of pressure a day.

After replacing the expansion vessel, a leaking pump, a leaky rad, 6 leaking radiator vents/caps, leaking hot cylinder aav, a clean with Fernox F5 and the addition of a leak sealer additive - I am now down to loosing <0.1 bar a day. Pressure is only lost when the heating is on.

I could live with this but I would like to try eliminate the remaining water loss.

One remaining area I think could be leaking is the aav at the circulating pump.

It's difficult to know if the pump aav is leaking as it is at an inaccessible location in the boiler. I wouldn't like to try and get my hand in there to check for water while the boiler is at temp. I am thinking of closing off the pump aav (manual system bleed is fine for me). Before I do this I would like to get others thoughts as I am not a plumber. (There does seem to be a lot of "crud" around the vent itself).

What problems could I cause by closing the aav at the pump?

Any thoughts would be gratefully appreciated.

Thanks !

(The boiler is a 10 year old Vokera Mynute 20SE).

 

[REDSAW]

well, it must have saved a fortune on getting a plumber in, well done.

 

[WHPES]

if you have a leak there will normally be the telltale signs of leaking (dried residues) if they are visible.

 

[coldwrench]

if you have a leak there will normally be the telltale signs of leaking (dried residues) if they are visible.

Hi Whpes,

Hmm, interesting, there is a lot of dried residue. So much so I didn’t want to rub it away in case it made matters worse. There may not even be a screw cap. It was difficult to tell with so much residue there. I can’t see it, I can only just about feel around with my fingers.

Should I take any particular precautions if I clean it off and close it off with a screw cap?

Thanks.

 

[ian macca]

have you checked the prv? if i replace a faulty expantion vessell i always replace the prv,

ian

 

[wnjswozo]

Start saving for a new boiler

 

[oldplumber]

if your expansion vessel was faulty you may well have blown the o rings/seals within the boiler some of which are in the sealed housi ng for the burner/heat exchanger, any leaks can be well hidden there as they dry out with all that heat. A leaking aav on the pump is symtomatic of an overpressurised system and normally reverts to normal once the expansion vessel is repaired. I am assuming this model is a combi as i dont know it to work on.

 

[coldwrench]

if your expansion vessel was faulty you may well have blown the o rings/seals within the boiler some of which are in the sealed housi ng for the burner/heat exchanger, any leaks can be well hidden there as they dry out with all that heat. A leaking aav on the pump is symtomatic of an overpressurised system and normally reverts to normal once the expansion vessel is repaired. I am assuming this model is a combi as i dont know it to work on.

When I replaced the expansion vessel, it wasn't because the pressure was activating the PRV. The pressure never went above 1.5bar. When testing pressure at the schraeder valve I was getting some water, so my thinking was a mere pinhole leak in the diaphram. I did check the external PRV pipe. Absolutley no water was leaking out there.

I think I'll go ahead and clean/close-off the pump aav, and see if that solves the leak. If not, I guess the only remaining possibility is the heat exchanger. Are the heat exchanger O rings something that can be replaced during a boiler service?

BTW - The boiler is not a combi.

Thanks !