When the heat goes on I can hear gurggling in the pipes which I assume
is air in the FHW system. I want to bleed this air off but am not
sure on how to go about it. It is a 3 zone system with 3 circulating
pumps. There are valves positioned on the return lines above each
pump. They look like outside faucet valves. Do I just open these
valves while the system is running to bleed off the air? Ok, I'm
actualy asking after the fact. I already tried doing this but the
flow was very slow, at times it stopped completely. I assumed this was
because the air was beng purged but I held a bucket there for a few
minutes and the flow never increased. Did I not wait long enough or
am I doing this wrong? If there was no air in the system I expect I'd
see a pretty good flow out of that valve, right?

Thanks

hey george try ask toh.org its ask this old house smitty

Ultimately it depends on the system and how it was hooked up. If the
installer planned properly for this, it should be easy.

Your method sounds right but you need to open the zone valve and run the
pump or the water will not flow. There may be a manual bypass valve which
allows water to circulate in the zone without the pump, activate that if you
have it. There may be an electronic solenoid valve in addition to the pump
or the pumps may serve that purpose themselves.

You will need a heck of a lot more than a bucket. Attach a garden hose to
the faucet valve and run it outside. When you open the valve and turn on
the zone pump, lots of water and air pockets will purge out the hose while
new water will fill the boiler from its inlet pipe (which should also
already be open). Run it long enough to replace all the water in the pipes
and observe the outlet hose for a smooth steady stream with no gurgling.

The way you did it, it sounds like you drained an isolated short section of
pipe, thereby adding more air to the loop. If you had been purging a large
amount of trapped air, it would probably hiss then be followed by lots of
water.

In the end, it might be worth the $ to have a heating guy come out and show
you how to do it properly once and for all. If you insist on asking us, try
posting a few pix (on your own webspace) and put the links here so we know
what you actually have. Even the same furnace can be installed a myriad of
ways to satisfy particular needs and space.


wrote in message
ups.com...
When the heat goes on I can hear gurggling in the pipes which I assume
is air in the FHW system. I want to bleed this air off but am not
sure on how to go about it. It is a 3 zone system with 3 circulating
pumps. There are valves positioned on the return lines above each
pump. They look like outside faucet valves. Do I just open these
valves while the system is running to bleed off the air? Ok, I'm
actualy asking after the fact. I already tried doing this but the
flow was very slow, at times it stopped completely. I assumed this was
because the air was beng purged but I held a bucket there for a few
minutes and the flow never increased. Did I not wait long enough or
am I doing this wrong? If there was no air in the system I expect I'd
see a pretty good flow out of that valve, right?

Thanks