FAQs on circulator pump leaks on hot water heating systems:

This article series will tell you how to find and fix the common points of leakage found at heating system circulator pump assemblies.

Q&A on Leaks at heating circulator pumps

These questions and answers appeared originally at CIRCULATOR PUMP LEAKS - be sure to see the heating zone circulator pump leak diagnosis and repair advice given there.

On 2020-01-09 - 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

On 2020-01-09 by Michelle

Dunkirk oil burner is leaking water in the front where the round seal is the connects to the pump motor

On 2019-02-07 - by (mod) - circulator pump leaks at bleed screw or valve?

There's surely a reason, William, though i can but guess at this point.

The bleeder valve usually has a tapered seat. Dirt, a scratch or gouge, damaged threads from over tightening, can leave the fuel unut bleeder vslve leaking.

Try removing the screw, cleaning and ins Pok ecting both screw tip and seat, and oerhaos try a replacement bleeder screw.

Watch out, don't glob it up with sealant or the pump may be damaged.

On 2019-02-07 by William massey

Anytime i bleed pump why wen i screw back it always weeps is their a reason??

On 2019-01-31 - 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.

On 2019-01-31 by Tom Bowen

Leaking at the impeller.

On 2019-01-19 - by (mod) - circulator pump start leaking after turn off the water supply

Perhaps because it has cooled down, allowing a metal Gap to open. Take a look closely and tell me exactly where the leak is occurring.

On 2019-01-18 by Tom Bowen

Why does my circulator pump start leaking only after I turn off the water supply to my pressure reducing valve ?

 

Question: circulator leaks if I turn off water supply to boiler

2018/12/31 Tom said:

If I leave the water supply on to the pressure relief valve my system runs fine but if I turn the water supply off to the PRV my circulator pump leaks ?

This Q&A were posted originally at HEATING SYSTEMS - home.

Reply:

Apologies Tom as I want to help, but I don't understand "water supply on to a pressure relief valve" - we do not supply water to a pressure relief valve.

We put a pressure relief valve or PRV on a water pressure tank, water heater tank, boiler, or other water-containing closed container so that it can open at over-pressure conditions to prevent a dangers BLEVE explosion.

See BLEVE EXPLOSIONS for details.

Watch out: assuming we're talking about a hydronic heating system (hot water boiler heat), a small water leak anywhere on the system will sometimes evaporate and thus be less than obvious when the system is hot, but may show up as a water leak when the system is cold.

Another subtle and in my opinion unlikely explanation is that your boiler pressure drops abnormally low when you leave its water supply off.

Some boiler or hydronic system leaks (such as at the circulator pump or its mounting flanges) occur or are visible only at higher pressures.

Check the advice given at

CIRCULATOR PUMP LEAKS

Question: boiler keeps kicking on and baseboards stay warm when they shouldn't

(Dec 11, 2014) Anonymous said:
My oil fired hot water boiler is equipped with 2 Taco 007 circulators supplying hot water to 2 zones of the house as well as providing domestic hot water for the shower and sinks.

Recently I've noticed that even with the zone 1 room thermostat set way low, the boiler continues to kick on and keeps the baseboard heaters warm. Does this sound like a problem with the circulator pump?

The service valve located on the boiler side of the pump seems to have some rust build up at its connection with the water pipe leading from the boiler itself. Might that be the issue? Any help someone could provide is greatly appreciated.

Reply:

Anon at the end of this page or in the ARTICLE INDEX found there see

CIRCULATOR PUMP WON'T STOP RUNNING

for diagnosis and repair advice.

Question: noisy circulator bearing

(Feb 4, 2015) Anon said

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

It was quiet for a weak 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.

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.

But 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.

(Feb 20, 2015) Donald Fletcher said:
T

hanks ..., 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 right to me.

Question: air in the hot water heating piping

(Mar 10, 2015) Mark said:
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.

Reply:

Mark see the diagnostic and repair tips at

• AIR BLEEDER VALVES
• AIR SCOOPS PURGERS SEPARATORS

Also see

AIR-BOUND HEATING SYSTEMS - home

...

Continue reading at CIRCULATOR PUMP LEAKS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• BOILER LEAKS CORROSION STAINS
• BOILERS, HEATING - home
• CIRCULATOR PUMPS & RELAYS
  • WHAT GOES WRONG WITH HEATING CIRCULATORS?
  • CIRCULATOR PUMP LEAKS
  • CIRCULATOR PUMP MANUALS
  • CIRCULATOR PUMP MOTOR or BEARING FAILURE
  • CIRCULATOR PUMP MOUNT LOCATIONS
  • CIRCULATOR PUMP MOUNT POSITION
  • MULTIPLE CIRCULATORS HOW TO HOOK UP
  • MULTIPLE HEATING ZONE CONTROL
  • TACO CIRCULATORS & CONTROLS
  • WEAK HEAT, WEAK CIRCULATOR, TOO COOL
• CIRCULATOR PUMPS vs ZONE VALVES

Suggested citation for this web page

CIRCULATOR PUMP LEAK FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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INDEX to RELATED ARTICLES: ARTICLE INDEX to HEATING BOILERS

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