"BillP" wrote in message
news

"Justin" jsheldon@ remove me lineone.net wrote in message
...
.But wouldn't the head of
water keep the feed under +ve pressure ? Both the cold and hot are 22mm
pipe. The AAV will be on a 15mm stub out of the top of the Tee

Hi Justin,

Maybe, not too sure what the dynamics of the system would be.I've just got
a
feeling that it would tend to draw air in. I've not yet seen a
manufacturers
installation guide requiring the addition of an AAV. Do you have the
manufacturers instructions for the pump you are fitting, or are you
following the other install as a guide. Providing the hot and cold feeds
to
the pump are made in such a way that air will not be drawn into the system
and the pump is situated at low level, there shouldn't be a need for the
AAV. Unless the manufacturer says different.



I can't seem to find the instructions now, but I've been using the other
install as a guide. I suppose when you first commision the system the vents
help expel the air, but manual vents would do the same.


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