The boiler is old, like 1964 old. It's a sunray iv. I have heat and
everything works fine. I just bought this house about a month ago. I
have waterfall sounds in my rooms which is air i'm assuming. I want to
bleed the system, but i'm concerned with the pressure. It's water not
steam, and only needs to go up about 10ft. Cold i have no pressure, the
secondary guage is set at zero, not sure if that's normal or if the
technician never set the normal reading guage? It get's up to about 5 psi
when heating. So, first should i have pressure when cold, even though
this is not a steam system. And if my pressure should read zero when
cold, how do i go about filling the system up then?
On Thu, 10 Dec 2009 17:42:10 +0000,
jeffmeitz_at_hotmail_dot firstname.lastname@example.org (minimeitz) wrote:
Your boiler has a max working pressure for hot water of 30 psi.
Anywhere between 12 -15 psi working pressure should be fine in your
Look at the make up water pressure reducing valve and see if it has a
lever on the top or if there is a bypass fill pipe. If it does have a
lever, that's the fast fill lever. Open it by pulling it until its
straight up and watch the pressure gauge. Close it when you get to
about 25 psi. Once you see pressure building open the pop off valve
to make sure it works. When you see water coming out leave it open
for a few and give it a good blow. Build up the boiler pressure again
then open the bleeders on the top of the system on each radiator or
high point, what ever your case may be.
If you don't have any coin vent type bleeders or maid-o-mists
(automatic air purgers) you'll need to build pressure as described and
shut all zones and work on one at a time. Purge the air by closing
the return line with the zone valve or a stop valve which ever your
case may be. Then open the bleed valve upstream of where you closed
off the return loop. Hopefully there is a place to hook a hose to.
The supply line always comes off the top of the boiler and the return
into the bottom. So basically you want to force the water all the way
through the loop unless you can let the air out from the top. If you
have to bleed the loop use a hose and a bucket. Attach the hose to
the loop drain on the return side and watch until the bubbles quit.
Run the circulating pump. Turn the gas off to the boiler when
bleeding the air out.
Make sure your expansion tank is in good condition and the bladder is
good or if its a air tank make sure its drained before you start and
if there is a sight glass on it replace the seals to prevent the
expansion tank becoming water logged. Its possible to break the sight
glass taking the compression nuts off. The old gasket can stick to
the glass causing it to break. You'll need a glass cutter designed
for a sight glass to cut the new one to fit. Buy all new gaskets,
nuts and washers to reassemble. Once you get the air out, adjust the
pressure on the boiler to about 10 psi and let the PRV and expansion
tank equalize pressure at temp and check the gauge. If the pressure
keeps rising you either have a PRV that's stuck open or the expansion
tank has no air in it and is water logged. If its all good fire the
boiler and watch the pressure gauge. Somewhere between 12 and 15 psi
is what you want to see at operating temp. 160-180 F.
There's are a lot of ways boiler are piped and valved I cant see yours
from here. Anything I've said may or may not apply to you. Your best
bet is to hire someone who knows what to do and watch him so you know
Good luck, merry Christmas and if you fuck something up don't blame
You definitely need an experience and licensed service person.
If that pressure is that low, it may indicate a doctored system to
avoid it leaking. As for air in the system, it may need manual bleeding,
but it might pay you to have automatic bleeders installed along with an
overall systems check. Just how much did you pay for this abode with
such antiquated mechanical systems. It should have been priced
accordingly. A good appraiser or a home inspector would have apprised
you of these things in advance of purchase. I might also add that old
systems seldom have a low water cutoff safety.
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