Very noisy circulator pump

ricardovj

Hey guys, I just bought a 20y/o house with an oil boiler and three heating zones. From what I can tell, there's one circulator pump for all three zones and three zone valves (there's another circulator pump which I'm not sure what it does. It is also a bit noisy but not much). One of the pumps makes a loud grinding noise through out the house BUT only when one zone is active, as soon as a second or third zone activate, it quiets down. I'm not super familiar with these systems so please bear with me!

Here's a quick video I shot: https://youtu.be/c3hgqDH4ugc

What do you guys think? Thanks!

MaxMercy

Hard to tell without hearing it, but Taco circs will often announce their impending demise with obnoxious noises, often for a long time before they finally quit. Grinding noises sound like the cartridge inside the circulator is starting to fail, but these will also make rattling noises when there's a bit of air in the system.

You can try bleeding air from your radiators/air handlers and see if that helps.

pecmsg

pictures from further away would help

Robert_25

You are hearing the death rattle from at least one of those circulators. From what I can see one of them serves your 3 heating zones, and the other is connected to an indirect water heater.

Unless the length of piping is very long in your heating zones, a Taco 0015 is not a great choice for a zone valve system. The pump curve is pretty steep and will likely cause velocity noise when only one or two zones are calling for heat.

Are your 3 zones all hot water baseboard?

Zman

What is your system pressure?
If you have a baseboard heat system, the lowest speed would be more appropriate.

HVACNUT

And what is the Hi limit setting? Boiler temp at 194° in the video. Too high.

Jamie Hall

Where is this offending pump in relation to the expansion tank? Agreeing with the above comments -- it's probably on its way out -- but the problem may be being made much worse by cavitation, which will kill a pump very fast. If the pump is not pumping away from the expansion tank, the cavitation will be much worse when only one zone is open.

EBEBRATT-Ed

Pump sounds noisy. Could be caused by debris in the system. Those pumps are lubricated by the water in the system. If the water gets dirty it can affect the pumps.

But it could be something else. Stand further back and take some more pictures so we can see the whole system

Intplm.

@ricardovj
It sounds like the dreaded death rattle but, also it sounds like there is air in your system and or low water pressure causing the circulator or circulators to cavitate.
Before changing things, make sure your water pressure is correct, then purge, purge, purge the air from your system. This should remove the air and renew the "dirty" water from your piping that can at times, cause this type of noise.

Also, take a good look at what @Zman says above. That is quite a large circulator for many residential applications. Consider changing the circulator to a more appropriately downsized circ.

If you do need to work on your circulator(s), please note that you are fortunate to have isolation valves on both the inlet and outlets of your circulators. If you didn't have these valves you would have had to drain the entire system, and that can be quite a big undertaking for someone who hasn't done it before. The valves will make it much easier to repair.