Noisy circulator pump in new installation

taubbri

Ok, before I get roasted too hard for the work pictured, I'm an unemployed software engineer that decided to replace his own boiler….

Every thing works as expected except the circulator(UPS15-58FC) furthest left in the photo has been noisy since day one. That manifold feeds 1/2 pex home runs to old cast iron radiators (the return for those is the lower manifold to the right. I've taken the pump apart and couldn't find any debris in it. This morning I woke up to it not able to self start on the lowest speed (the one I have it set at). I replaced the pump and the new one is noisy just like the last one. Also, for what it's worth, the other pump being on/off has no impact on the noise.

Is it possible that the 1.25 to 1 in reducing coupling before the pump is the source of my problems? Is the head loss in that circuit so low that the pump is eating itself (is this even a thing that can happen)?

Any thoughts/insight would be appreciated!

Jamie Hall

Can't quite make it out, so I'll have to ask. Where in the circuit does the expansion tank and automatic feed valve tie in? And what pressure (looks like about 15 psig?) is the tank and feed set at?

What I'm concerned about is that the noise may be cavitation at the inlet to the pump. Whether this might happen is related to what is between the point of constant pressure at the tank and the inlet to the pump.

By the way — nice neat job of putting it together.

taubbri

The expansion tank is connected after the returns for both circuits. If you're looking at the picture it's the 1/2 in copper pipe to the left of the boiler. The pressure is ~16psi.

hot_rod

what type of noise? Squeal like a dry bearing? Gurgling like air inside?

taubbri

If I had to describe it, it would be a rattling noise. It sounds as if a piece of something is in the pump, but with this being the second pump I can't really think of a way that this would happen.

bjohnhy

Looks very nice!

That sound could be air in the pump. If it was air it would have cleared after a few hours. I suppose it could be a piece of solder bouncing around in there. Have you taking the pump out and tried to shake it out? The reducer is not the source of problem. Sometimes the IFC check valve can be off kilter and rattle. You make it sound like you are getting good flow through there. How does it change if you switch from low med to high?

Is that taco Pressure reducing valve/back-flow preventer supposed to be installed horizontal? I thought they were, I'll look it up.

hot_rod

A 4 mm or 5/32" allen wrench will take the 4 bolts out. Gently tap the motor to pull it and the impeller out. See if something is rattling around the impeller or body.

Turn the power off first, and close the iso valve.

Another possibility is a check valve in the discharge port of the pump. Pull the entire pump out of the flanges to inspect that. A ball of solder for instance may not be able to flush out of the piping and works back into the pump when the velocity increases with the pump spinning.

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PC7060

https://forum.heatinghelp.com/discussion/comment/1835788#Comment_1835788

agree, very nice looking install. All the copper looks to be sweated; no ProPress. You didn’t happen to see @Mad Dog_2 lurking around? 🤣

Kaos

What's going on in the corner there with your near boiler piping?

Small amount of air in the system can also cause rattling noises form the pump, air separator before the bump doesn't guarantee all air is removed.

taubbri

Thanks for all the suggestions.

@bjohnhy; flow is not an issue. The noise is directly proportional to pump speed. Also, I read the install manual for the taco PRV a few times and couldn't find anything telling me it needed to be mounted horizontally and I though it looked better where it ended up….

@hot_rod; I did that to the old old pump before I replaced it. found nothing. I'll do it again on the new pump and report back. The only working theory I have a this point is that there is something that works it way back down when the pump isn't running. When I take it apart again I plan on closing the isolation valve below the pump with it running and then cut the power.

hot_rod

is that a swing check above the DirtMag.? If so they are problematic in hydronic system. The need a lot of flow to hold them completely open. They will rattle if the swing is floating inside.