Noisy pipes that sound like too high of flow.

Mike Bushard

I'm working on a four-story apartment building built in the mid 1960s that has 18 units. Each unit has an upper and lower level with a zone valve and thermostat on each level, so there are a total of 36 zones. The two most remote units from the boiler on the west end of the building have this screaming high flow sound coming from the heating pipes in the wall. When I open all four zone valves in these two units, the noise pretty much goes away. But when they are closed, it sounds like a lot of water trying to go through too small of an opening.
I've tried to purge air from the top floor, most remote, unit but only get water out of a garden hose connected to a boiler drain valve on the baseboard radiator after running it at least 10 minutes.
I had worked on the Bell & Gossett series 60 pump before, bringing it to the B&G rep. who put a new impeller on it and swore it was the right one for the pump. When I installed the pump, the impeller just barely fit into the volute.
Is this pump pumping too much water? Do the impellers get sized to the system not the pump? Is there a faulty bypass/balancing valve? Where? How many gallons per minute should there be pumping through the 3/4" copper pipe in the most remote units? Is it a balancing problem?

J.C.A._3

Is there,

Any kind of pressure differential unit at the boiler or between the feed and return piping? We have an apartment complex with between 6 and 15 units in the smaller buildings, all controlled by zone valves. The worst offender was treated to a pressure differential valve (Stadler I think) but the problem wasn't the flow as much it was failing pipe insulation causing banging during expansion, and slamming as the zone valves closed at the various offsets in the pipes leading to them.

Sounds like it's time to rip open a few ceilings and find the condition of the insulation, if any. Another thing to check is how the pipes are supported out to their destinations. Loose and missing hangers could be causing a vibration that is being exaserbated through the piping itself. Just an educated guess! Chris

J.C.A._3

Bump,

I'd like to hear from someone, if I missed something.

I usually see this in older apartment complexes and find the things I found, most of the time.... Chris

Weezbo

well, that belive it or dont is a great puzzel for the mathma..

tician ...got circuit setter or some such on supply and return side of pump?