Heating System Circulator Pump Noise FAQs

Hot water heat circulator pump & relay noise questions & answers

Circulator Pump Noise FAQs

Tip: For all circulator pump noise diagnosis and repair

see CIRCULATOR PUMP NOISE REPAIR - noisy zone circulator zone valve, or a bad circulator relay

For noises traced to the circulator pump motor,

See the diagnosis and repair procedure

at ELECTRIC MOTOR WON'T START / RUN 

Also

see ELECTRIC MOTOR NOISE DIAGNOSIS

We have a humming buzzing Taco circulator pump and baseboards are slow to heat

My circulator pump (Taco 007) started humming or buzzing a few days ago.

But hot water is definitly getting circulated to baseboards. So it appears to be working

Besides the buzz the only thing unusal is that is seems some baseboards are taking longer then usual to fully heat. But I can't really verify that. I may just be imagining that. On 2014-03-02 by Matt -

by (mod) -

Matt: maybe using a mechanic's stethoscope or even a simple pen or iron rod you might be able to decide if the buzzing is in the motor itself (bad bearing, new motor time) or in the circulator relay (replaceable electrical part)

If the pump is not working (or a circulator relay is not working so is buzzing) you may still get heat but very slowly as the hot water only circulates by convection.

Detailed diagnostics that you should review are at

CIRCULATOR PUMP NOISE REPAIR - noisy zone circulator zone valve, or a bad circulator relay

ELECTRIC MOTOR HUMMING - for any of the electric motors found on heating systems including oil burners, fans, blowers, pumps

LOW VOLTAGE TRANSFORMER, TRANSVERTER DIAGNOSIS - a failing transformer powering a circulator pump relay or boiler primary control

One of my zones has no heat and the circulator is humming

Hi I have a forced hot water baseboard syst. One of my zones is not getting heat.

The circulator seems to be working because its humming (problem?) there is no air in the system.

What could it be? On 2017-01-14 by Dom

by (mod) - some circulator noise is normal

Dom

I agree that on many circulator pumps there is a motor noise that might described as whirring or humming when the pump is running. Others such as many Taco models are nearly silent.

But when one of your zones are cold and you think the circulator is running, I don't assume there's no air in the system since air blocks can be sneaky, subtle - e.g. blocking a horizontal run that just doesn't allow air to get up to the nearest air bleeder.

Other issues: a blockage in the piping, a zone valve that you think is open when it's not, or a circulator whose motor runs but whose impeller is damaged or broken completely. In that case the motor runs but the circulator never moves water.

If this is the case you may find that the hot water pipe on the inlet side of the circulator is hot but on the outlet side or just a foot from it, the pipes are cool (too close to the circulator to make airbound heat my first guess).

Feel the pipes. Follow the heat - or the cold. That usually points to the trouble spot.

If pipes are hot leaving the circulator for a meter or two, but cold at baseboards or radiators, start looking for an airbound problem.

Follow the procedures at AIR-BOUND HEATING SYSTEMS. Keep in mind that a bolus of air can be in a horizontal piping run well before an air bleeder valve so you may need to do a bit of water bleeding to be sure there's no air in the system.

How do I fix a noisy circulator pump bearing when I changed the pump position?

My Grundfos 15-42fr circulator was recently moved from a vertical position to horizontal.

It was quiet for a week or so and began to make a noise just like the Taco circulator in this video.

Is this noise a bearing failure? see video belink below. (Feb 4, 2015) Anon said

Reply:

Sounds like a bearing failure to me. Sometimes changing position of an electric motor combined with worn bearing(s) will display a problem that has been developing for a time.

Watch out: While I wouldn't expect a misalignment between motor and pump impeller on a Grundfos Grundfos UP15-42FR, a warning for other readers: I have seen circulator pump failures (more often with older B&G circulator pumps) due to a misalignment of the pump mounts.

Donald Fletcher said:

Thanks. I'll try to hold out till spring, then will replace the circulator. All the talk about pulling away made me decide to place it on the hot side when I put the new indirect in.

When I replace it I think I'll put the new back on the return side. I will also place a Spirotop vent in to make sure the pump don't run with air for any length of time.

Reply:

Sounds OK to me. Keep in mind that you risk running out of heat in cold weather when you defer this repair.

If the circulator fails solid, you might need the help in keeping some heat going that we explain at

BYPASS a BAD CIRCULATOR

One of my heating circulator pumps keeps banging

I have hot water circulator system 4 zones but one circulate a pump and always banging - On 2019-11-11 by Anonymous

Reply by (mod)

Start by looking at the circulator pump and motor assembly itself. Is the banging noise coming from the pump or its control relay? If so there is a failed part that needs replacement.

But more likely the banging noise is coming from sudden starting or stopping of water flow through the heating zone piping.

See the diagnosis and repair advice

at BANGING HEATING PIPES RADIATORS

And if your heating system uses zone valves in addition to one or more circulator pumps

see BANGING HEATING ZONE VALVES

Can I Replace a noisy circulating pump with a different model?

I have a boiler system with two circulating pumps. One is a 106189 which is leaking. It was replaced about 20 years ago.

The other is a 102210 that is extremely noisy and has been there forever, it vibrates the whole system. Can I replace both with the 106189? - On 2018-10-12 by Gary R

by (mod) - yes, possibly with minor piping changes

Gary you can usually replace one circulator pump with a different model;

If the new circulator is not a straight "bolt-on" replacement then the plumber will need to cut and adjust piping lengths and fittings for the new pump.

If you want to combine two zones onto one circulator you'll need to change some piping and add a zone valve.

Circulator pump is Noisy and we have no heat after repairing a heating piping leak

We have a boiler system in our home we had to turn the water supply off due to a pinhole in a copper pipe.

We fixed the pinhole leak.

When we turn the system back on the boiler itself will kick on but we are not getting any heat from the registers.

The circulator pump is making a unique sound the pump itself is vibrating and it's hot but the pipe leading from the top of the pump is cold any suggestions - On 2017-11-12 by Circ.

Reply by (mod) -

Circ

The noise could be because your circulator pump is running dry.

Watch out: don't keep the pump power on if the pump is running dry: that might damage its impeller assembly.

Check the water level in your boiler and be sure the system is filled.

Then see

AIR-BOUND HEATING SYSTEMS

To see the diagnostic and repair suggestions that most likely address a situation you described

Circulator pump was run without any wanter, now it hums and may not be working

I had some boiler maintenance done. The technician forgot to open a ball valve that that leads to the circulator pump feeding my hot water tank.

The pump ran for 18 to 20 hours without water circulating.

After I opened the valve the tank eventually reached temperature but during the process there was a humming sounds coming from the circulator. Should I be concerned about pump wear (e.g. bearing, fins ...etc)? On 2015-08-26 by Bob

Reply by (mod) -

Watch out: If the pump was running "dry" it could have suffered wear or damage to the impeller assembly and possibly even to a drive shaft bearing.