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PSWired

join:2006-03-26
Annapolis, MD

Hydronic heat pipes banging

Yesterday I replaced the circulator in my 2-zone hydronic heating system. There is a single circulator on the return side of the system and two zone valves on the supply side of the system. I drained the system to replace the circulator.

After replacing the pump, I refilled the system and purged the air from each circuit using the zone waste valves and autofiller. Everything is working now except that each time a zone shuts off, I get a huge bang throughout the system. It's happening in both zones.

When I moved in here a much milder bang occurred when the zones shut off, but I solved that by removing one spring from each zone valve, causing them to shut more gracefully and avoid the banging.

What did I manage to change to cause this?



tp0d
yabbazooie
Premium
join:2001-02-13
Carnegie, PA
kudos:5

Did you change the pump with exactly the same model, or is it a higher GPM pump?

Also sounds like your zone valves are shutting off too fast, before the pump slows. What is the make/model?

A water-bound expansion tank could also cause this problem. What type do you have

-j
--
if it aint broke, tweak it!!
currently on FiOS (kick aZZ!)



PSWired

join:2006-03-26
Annapolis, MD

The pump is identical. Taco 007-F5.

I'll check the zone valves tomorrow, but they're Honeywell and are motor actuated, spring return.

Expansion tank seems ok. It's a ~2 gallon bladder tank. Tapping on the air side sounds hollow, tapping the water side sounds full.



PSWired

join:2006-03-26
Annapolis, MD
reply to tp0d

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PSWired

join:2006-03-26
Annapolis, MD
reply to PSWired

Well, I think I've found the problem.

Whoever installed my old circulator must have reversed the pump orientation with respect to the motor... I have the new circulator installed backward, pulling water out of the bottom of the boiler

Time to drain the whole system again and redo this whole thing...



tp0d
yabbazooie
Premium
join:2001-02-13
Carnegie, PA
kudos:5

ahhhhh that'll do it.. the zone valves are meant to stop flow in one direction, not reversed.

-j
--
if it aint broke, tweak it!!
currently on FiOS (kick aZZ!)



PSWired

join:2006-03-26
Annapolis, MD

Drained the system and flipped the pump around last night. No more banging pipes.



cdru
Go Colts
Premium,MVM
join:2003-05-14
Fort Wayne, IN
kudos:7
reply to PSWired

said by PSWired:

Whoever installed my old circulator must have reversed the pump orientation with respect to the motor... I have the new circulator installed backward, pulling water out of the bottom of the boiler

Time to drain the whole system again and redo this whole thing...

Just reverse the wires. Duh.


PSWired

join:2006-03-26
Annapolis, MD

Or just put in some earplugs