Circulator Pump Leak FAQs

Q&A on where leaks occur at zone circulators & how to fix them

Circulator Pump Mounting Flange Leak FAQs

Tip: leaks at the circulator pump mounting flanges are common if either the flange gasket fails or the flange bolts are not kept snug.

If you see water stains or drips like those in our photo above, call your heating service company for repair. Acting promptly can avoid a much more costly repair.

A pair of circulator flange gaskets costs $10. to $30. U.S. depending on whether or not additional flange parts are needed.

Below: common circulator flange gaskets.

Pipe connecting Taco circulator drips water

Hi,

I have a Weil Mclain ii boiler and for the last day and a half the pipe connecting the taco cartridge circulator that points to the ground has been dripping water.

The dip isn't a steady flow, it stops at times but than continues. I'm not sure if that's a issue, I've never seen my boile drip water and that why is concerns me.

The valv connecting the pipe and cartridge circulator is extremely rusted and I'm not sure if that is the issue. I also can't get someone to look at it for a few days, please let me know if i have big issue on my hands. Thank you On 2017-03-03 by Jack

by (mod) -

Typically I see leaks at the circulator mounting flanges - less often within the pump itself.

The taco has a replacable pump cartridge.

Look carefully to see if you can spot the leak, but do not pick at rust and corrosion or it may get quickly worse.

It's time to call for a replacement by your service tech.

Shown below: a set of replacement circulator pump flanges as well as their flange gasket O-rings for Grundfos circulator pumps - less than $30. U.S.

Circulator Pump Leaks Into Electrical Parts FAQs

Tip: See the detailed advice at CIRCULATOR PUMP LEAKS

What's the Right way to fix a leaky circulator pump

I have 2 zone upstairs/downstairs baseboard heat all baseboards are cool except for the upstairs bathrooms which are directly above furnace,

I noticed the circulator pump appeared to have water leaking from the electrical connection compartment when I opened it up to check for ac it had a bit of water/grease in the compartment. I'm assuming a seal in the pump has ruptured and shorted the motor.

The output and return both go into the ceiling so I'm assuming from reading the other questions that it's just convection warming the rooms above.

The furnace appears to be working fine and the pump feeds two zone valves above. Am I on the right track? (Jan 9, 2015) Ed

Reply: safety warning about leaks into electrical components

Ed

Watch out: water leaks into any electrical control or component create a risk of dangerous, even fatal electric shock - in addition of course to damaging the equipment and leading to loss of heat.

Sounds as if the leaky circulator needs to be replaced and that perhaps as well air has leaked into the heating system piping. First replace the circulator. Keep me posted.

Leaks at Circulator Pump Motor / Shaft FAQs

Water leaks between circulator motor coupling & pump

I woke up this morning to the sound of air in my hot water baseboard system. When the pump is not running there is water leaking from the area between motor coupling and the pump.

I have four heat zones but only one is getting heat. Then the relief valve blew. I shut the system down. How do I fix the leak?

I neglected to inform you that my pump is a B&G that is close to 40 years old. (Mar 10, 2015) Mark said:

Reply:

Mark

Water leaks at the circulator motor pump shaft coupling usually are a bearing or seal failure in the pump unit itself.

It's often possible to keep the circulator motor and just replace the mechanical circulator pump assembly - something your service tech can do.

For getting rid of air in your hot water heating system see the diagnostic and repair tips at

• AIR BLEEDER VALVES
• AIR SCOOPS PURGERS SEPARATORS
• AIR-BOUND HEATING SYSTEMS - home

Circulator pump leaks at the impeller assembly

Leaking at the impeller. On 2019-01-31 by Tom Bowen

by (mod) - signs of a leaky circulator pump shaft seal

Tom that's typically a bearing or shaft seal failure.

I've seen repeated circulator pump leaks at the impeller when motors were replaced but the motor-impeller-mount brackets were not properly aligned.

Replace the impeller assembly.

Leak at circulator pump connection to motor

Dunkirk oil burner is leaking water in the front where the round seal is the connects to the pump motor On 2020-01-09 by Michelle

by (mod) - leak at circulator flange on Dunkirk boiler

Michelle

It sounds like you're describing a leak in a circulator pump of course not the oil burner itself.

That's probably a shaft bearing or seal leak. Although it's repairable technicians virtually never repair those in the field. They're more likely going to want to install a new motor or an entire new circulator assembly.

If you just replace the motor be absolutely certain that the technician mounts it dead true to the actual pump assembly otherwise the new motor will be damaged a leak in the same place