purging procedure for hydronics

T.W.

Hello,
I have encountered several opinions on how to properly purge a residential hot water boiler. I usually have
an FB-38(B&G prv)on the water makeup with good city water pressure for fast feed at approx.20#/10min.Isolation/purge valves on the supply & return & an additional ball valve for the air vent on a typical 2 zone system.I purge one at a time & usually i leave the 2nd flr. last. Turn off the purge & then the makeup......slowly drop the pressure to approx. 12-13# & turn off purge or draind at air vent.
Please advise or refer to proper literature on subject

T.W.

purging procedure for hydronics

Hello,
I have encountered several opinions on how to properly purge a residential hot water boiler. I usually have
an FB-38(B&G prv)on the water makeup with good city water pressure for fast feed at approx.20#/10min.Isolation/purge valves on the supply & return & an additional ball valve for the air vent on a typical 2 zone system.I purge one at a time & usually i leave the 2nd flr. last. Turn off the purge & then the makeup......slowly drop the pressure to approx. 12-13# & turn off purge or draind at air vent.
Please advise or refer to proper literature on subject

Brad White_9

You did not say

if you are getting the results (an essentially air-free system) with the way you are going.

I have trouble following your procedure so here is mine:

1) Connect hoses to drains (very important!)

2) Isolate all but the subject zone to be purged if possible.

3) Connect supply water hose to valve downstream of circulator and flow check. (=Drain valve for zone supply side).

4) Open outlet drain valve upstream of return isolation valve.

5) Open cold water valve. Stand by return outlet hose.

6) Observe flow of water and air. Once surging/gushing/splashing stops, go another 30 seconds or so.

7) Slowly close the outlet valve.

8) Close the CW inlet valve. Adjust to pressure. (Hose-Bibb gauge is handy this way.)

9) Keep purged zones isolated until rest of system is filled. Open each valve to system and adjust to pressure. Allow for fill height (feet x 0.433) plus 4 PSIG for top pressure. Done.