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Circulator pump leak at mounting flange (C) Daniel FriedmanCirculating Pump Won't Stop FAQs
Q&A help fix circulator pumps that just won't stop running

FAQs about heating zone circulator pump wont' stop running.

Tthis article series explains how to diagnose & fix a heating circulator pump that runs even when we are not asking for heat.

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FAQs Heating Zone Circulator that Won't Stop Running

a heating boiler circulator pump setThese questions and answers about troubleshooting and fixing a heating zone circulator pump that won't stop were posted originally at CIRCULATOR PUMP WON'T STOP RUNNING - you may want to check the advice given there.

On 2020-01-03 - by (mod) - Circulator pump won’t stop when I turn it off

Jaime

If you are turning off electrical power to the circulator and it won't stop then we know that there is at least a bad electrical switch that needs to be replaced.

Lets next look through the diagnostics on the CIRCULATOR PUMP WON'T STOP RUNNING page

as that is an organized way to step through causes of a circulator pump that just continues to run no matter what.

On 2020-01-03 by Jaime

Circulator pump won’t stop when I turn it off it’s continues to run I changed thermostat what else should I do

On 2019-10-27 by (mod) - caretaker of my apartment building say how he hoped the boiler doesn't explode

Andrea

Doubtless you understand that nobody can accurately diagnose a heating system malfunction or safety hazard by brief e-texts; you need an onsite expert, a trained heating service technician.

We can't know if the caretaker is a trained heating service tech who has actually observed something clearly dangerous or if s/he is speaking more generally.

Watch out: if the heating equipment is unsafe or even thought to be unsafe by building maintenance people it ought to be shut down immediately.

You might want to notify the building management and owner in writing that you are concerned about not just loss of heat but a possible building safety hazard. Sometimes putting that in writing helps.

Depending on where you live there may also be a rental authority or building safety department who can help you out.

On 2019-10-27 by Andrea

Hello,
So I am not sure what to do here. This past Friday, I overheard the caretaker of my apartment building say how he hoped the boiler doesn't explode before it can get checked out on Monday. He went on to say that my landlord was too cheap to pay someone time and a half to come out that Friday evening.

Thinking he was joking, I went on about my business. Then saw him again in the hallway and asked if he really thought it could explode, he said he was going to keep checking water levels all weekend and that it might be a little colder in the building this weekend because theyd be turning the heat down.

I have to say, I really don't know anything about boilers, but I havent been able to stop thinking about this all weekend and have been worried ever since he made that comment.

I'd like to believe theres more to the situation I just dont know about, and that they wouldn't be jeopardizing the lives of all tenants in the building. I'm wondering if I should not worry about this, or if there is maybe something I should be doing?

Thanks in advance for any info or advice.

On 2019-03-07 by Mike G.

Thanks! I will look into that.

On 2019-03-06 - by (mod) - intermittent circulator pump stop-start

I'd look for a loose or corroded electrical connection first, starting right at the thermostat and following that wire, then perhaps a failing circulator relay.

On 2019-03-06 by Mike G.

I have a 30 year old hot water boiler baseboard heating system in the house we recently bought.

For the past month or so the circulating pump will turn on and then sometimes 1, 2 or 3 seconds later turn off.

It will still heat the house and run normally when called for heat but it does this intermittently between cycles, every 2 to 5 minutes. I know very little about these systems as this is my first time having one, but this frequent on and off cycling doesn't seem normal to me. Could the pump be going bad? Could there be an issue with the wiring in the thermostat causing the pump to cycle when it shouldn't?

Any help is appreciated. Thanks!

Mike

On 2019-01-06 - by (mod) - insulate the circulator pump?

Chris

I would not insulate the circulator pump for just the reason you give: it may overheat, shortening motor life.

A clue that's worth looking into is just where the circulator pump is installed.

While it can work pretty much anywhere in the piping loop, old timers like me prefer to see the circulator installed on the return side of the heat piping loop - water there is a bit cooler, which the pump then enjoys and which can give it a longer life.

On 2019-01-04 by Chris

I have in floor radiant heat and I have spent a bunch of effort to insulate all the hot water pipes that are exposed to conserve heat loss and make it as efficient as possible. My question is: I notice the circulation pump is very hot, ergo probably losing heat through convection the same as un-insulated water pipes, should I wrap the pump or will that cause it to be too hot internally and possibly damage it? I can't imagine it would hurt it but thought I should ask

On 2018-03-24 - by (mod) - circulator runs often in order to heat the hot water as well as provide heat.

Lindsay

Some heating boilers also include a hot water loop that can be used to heat a separate hot water tank (an indirect fired water heater) used to provide domestic hot water for washing and bathing

. If you have an indirect water heater installed and a single circulator pump serving all of your heating (and water heater tank) zones, then a call for heat at any thermostat OR a drop in temperature in the indirect water heater will turn on the circulator.

But a circulator that is running for just three seconds and then shuts off sounds to me like a circulator control or thermostat or temperature sensor problem that needs repair.

On 2018-03-24 by Lindsy

I was informed that the circulator runs often in order to heat the hot water as well as provide heat. But it runs and shuts off and then runs again 3 seconds later way too often...like every 11 minutes? is it broken?

On 2018-03-24 by (mod) - circulators also used on indirect water heaters

Lindsay

Some heating boilers also include a hot water loop that can be used to heat a separate hot water tank (an indirect fired water heater) used to provide domestic hot water for washing and bathing.

If you have an indirect water heater installed and a single circulator pump serving all of your heating (and water heater tank) zones, then a call for heat at any thermostat OR a drop in temperature in the indirect water heater will turn on the circulator.

But a circulator that is running for just three seconds and then shuts off sounds to me like a circulator control or thermostat or temperature sensor problem that needs repair.

Also see INDIRECT FIRED WATER HEATERS

On 2018-03-24 by Lindsy

I was informed that the circulator runs often in order to heat the hot water as well as provide heat. But it runs and shuts off and then runs again 3 seconds later way too often...like every 11 minutes? is it broken?

On 2018-02-06 by (mod) - remove thermostat wire connections to start diagnosis

First step: where are you: country and city. IN some locals such as most of Canada, circulators are wired to run continuously during the heating season. The thermostat turns the boiler on or off. This gives more even heat distribution and helps avoid frozen zone piping.

Next step: continue diagnosing by removing thermostat wires at the circulator or Zone controller

If the circulator stops then the thermostat was calling for heat - OR its wires are shorted so as to appear to be calling for heat.

Of course if the circulator is running but no heat is being delivered then start by checking to see if the boiler will run.

If the boiler is hot and the circulator is running but no heat is being delivered to the radiators or baseboards

then see AIR-BOUND HEATING SYSTEMS - home

On 2018-02-04 by W.Sharpe - Circulator Pump Will Not Shut Off

Circulator Pump Will Not Shut Off

Three Taco zone valves on one Taco circulator pump. All getting proper voltage and confirmed working. Boiler hi-lo set& working properly. Regardless of zone demand for heat or satisfied & regardless of boiler temp, and confirmed 110V across C1 & C2 terminals, C1 ( Honeywell L7224) indicator & pump stay on! This is a new behavior, and was not the case before.

Even when I power down the system, wait 30 seconds or even 2hrs, when reenergized, 10 seconds of silence, C1 indicator light goes on, followed by a relay click, and circulator turns on. This is with no TT demand and BT above limit.

Absolutely frustrating as to why the Aquastat is now turning on the relay/circulator for no need or reason.

The MAJOR CONCERN is, the pump is on the return side, in-between closed zone valves and boiler. A total distance of <2'. not much room for relief to the impeller, sucking away like someone trying to suck a just served wendy's shake through a straw! the motor is very hot.

then i've seen on a couple of discussion sites, "no harm will come to the circulator". sounds like b.s. from a taco sales rep to me.

question is, what happened? why is the circulator suddenly running non-stop? is there a fix? btw, it is rather cold, 15 - 20 outside, & no, this doesn't have an outside sensor. but we've had colder days.

for now i'm running heat, and when up to temp, manually turning off boiler power at top of stairs, sleeping in recliner for 2hrs. waking up to turn on the heat for another warming. lather, rinse and repeat.

your valued advise?>

On 2017-12-28 by SteveC

I have a boiler that is down and want to know if the circulation pump (multi zone) should be turned off of left on while the system is fixed (2 days)? Any harm either way?

On 2017-11-26 by (mod) - no heat after repairing heating piping leak

Circ

Please try using the search box just above to find our diagnostic article series using this phrase

AIR-BOUND HEATING SYSTEMS

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

On 2017-11-12 by Circulator pump

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 fix the pinhole

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 2017-11-26 by (mod) - my circulator pump shuts off before reaching desired temperature in the home

The problem could be a bad circulator motor or circulator relay, but more likely the problem is that someone in the house is running hot water and the hot water is made by a tankless coil in the boiler and the boiler temperature drops.

When that happens the system is designed to give priority to the person in the shower

If that's not the case, that is if no one's in the shower when this problem is happening then we're back to looking at the circulator pump motor and circulator relay

On 2017-11-11 by ned

my circulator pump shuts off before reaching desired temp. it comes on again after 15 min then shuts off again . it takes oyery long time to get the right temp

On 2017-01-17 by Dave

Boiler when heat shut off my pump stay running it is set up with economaster control what can I test or is the bad

On 2016-11-29 by tom k

I currently have a oil-fired boiler for heat and domestic hot water.

Because tenants leave thermostat setup to Max even on days where temperature is 60 or above is there a way to install a switch to cut off or isolate the circulating pump so the boiler will continue to heat hot water but not push hot water up the system

On 2016-01-25 by Martin F.

i currently have a problem where my boiler will not shut off except only when using the master switch.

I have 4 functioning thermostats in my house (1 basement, 2 main level, 1 second level) and checked each but no issued. Shutting off the boiler via the t_stat does not help.

Ive checked the control valves and im not quite sure but it seems like one or two might be malfunctioning - pipes to the control box are hot/warm while warm/cold on the other side but i dont know if that would cause the boiler to not shut off...

On 2015-12-19 by (mod) -

Ed,

If the thermostat wires were disconnected at the circulator end and the circulator keeps running, I suspect a bad relay or control.

On 2015-12-17 by Ed

I'm dealing with a taco circulator pump that is running non stop.
I discovered it when the temperature in one zone was climbing way beyond the setting (set to 70, baseboards still hot when reading 75-77degrees0.

I've followed the suggestions on how to troubleshoot to no avail. I was to the point that every thermostat was completely disconnected from the zone valves, and the zone valve wiring was completely disconnected from the boiler/circulator.

On 2015-09-17 by Karena

Hi, Dan,

I live in a condominium building (in Canada) and all suites have radiant floor heating. Except for the warmer months in the summer, it is much too warm in my suite so, I always have the patio door and/or window open and in turn, I have an unpleasant draft. I can constantly feel the heat coming from the floor even though my thermostat isn't calling for heat. In fact, it is very rare that I've had to turn the heat on.

Approximately two-thirds of my suite is affected by this heating irregularity. In my suite, I have two thermostats and the area that I don't have a problem with is controlled by the other thermostat. I've had the one thermostat replaced, but the issue hasn't been resolved.

This same thermostat is the only control for the air conditioning, which works properly. Also, supposedly, the valves are all closed. There has been several plumbers/HVAC technicians through our suite (and all of the suites in our building) and they can't seem to fix the problem.

I have been told by the condo board that the issue isn't to do with the boilers, but I'm not sure what to believe. I would very much appreciate some advice as I'm at my wits' end!

On 2015-08-26 by (mod) -

If the pump was running "dry" it could have suffered wear or damage.

On 2015-08-26 by Bob

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 2015-03-07 by (mod) -

John,

Yes. Look for a misfired or shorted thermostat wiring problem.

On 2015-03-06 by john s

new hot water natural gas boiler, 4 zones , I have the thermostat off upstairs , but I continue to get heat, have a circulator running all the time, my installer is returning in a couple of day , my ? is my fuels bills are crazy , $370 every 3 weeks , could that be the reason

On 2014-11-20 by Anonymous

I'm going to try that tomorrow. I think the previous owners put two pumps onto one zone relay. Not sure if that's possible, but there's a whole lot of wires and junction boxes in the boiler room so Itll take some time narrowing it down.

On 2014-11-19 by (mod) -

Matt did you try just disconnecting the zone relay?

On 2014-11-19 by matt

I don't have electric zone valves only the Flow check valves which have been replaced. I have Honeywell zone relays connected to the circulators. I'm wondering if the zone relaying shorting but I'm not sure how to find out

On 2014-11-18 by (mod) - troubleshoot my zone relay

Matt

I suspect that

The zone valve is latched open - leaving an end switch turning on the circulator

The zone valve motor has failed and is stuck open - leaving an end switch turning on the circulator

The thermostat wires are shorted

Start by disconnecting the thermostat wires at the zone valve.

If the valve has a manual open/close lever see if it can open and close the valve.

On 2014-11-1 by matt

I'm trying to troubleshoot my zone relay. One zone keeps calling for heat with the thermostat off. I replaced my flow control valves thinking it was convection heat, and replaced the thermostat. The circulator seems to be shorting but I'm not sure how to narrow down the problem.


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