Heat Won't Turn Off FAQs

Diagnostic questions & answers explain how to turn of un-wanted heat: radiators, baseboards

Furnace Heater Won't Stop Running FAQs

Furnace won't turn off

I have a Borg Warner unit and the blower and burner keeps running.

I installed a new fan limit switch but I noticed once I turned th gas back on the system reached fan on setting the fan came on and when the unit continued to run I turned the thermostat off and the fan continued to run.

So I turned the breaker off to the fan and the burner kept on burning, it would not shut off unless I turned the pilot valve off or the main gas valve.

Also the gas valve has a 2 wire connection on it.

One wire I assume is coming from the thermostat and the other wire I think should be wired to the fan load limit side.

I cannot figure out why the burner will keep running no matter what unless I turn the gas off. (Jan 2, 2013) Tom

Reply: If the thermostat is not calling for heat and the burner won't shut off, yours is an Unsafe heater, turn it off immediately

Watch out: you are describing a dangerous condition risking fire or carbon monoxide poisoning. You should turn off the system and call a trained heating service technician for repair.

Tom see FAN WONT STOP - LIMIT SWITCH

as a place to start diagnostics. Also check for shorted thermostat wires that keep calling for heat.

More help is at HEAT WON'T TURN OFF - topic home

 

Why does the furnace fan come on even though the thermostat is in the off position

Why does fan come on even though the thermostat is in the off position, no heat comes out just air, even took batteries out still fan comes on and off (Apr 8, 2015) lkmoore2009@live.com

Reply: furnace blower fan may be turned on by control at the furnace fan limit control, not the thermostat

LK

Forced warm air furnace fans are controlled by a limit-switch on the blower assembly. The fan might turn back on at the end of a heat cycle if the heat exchanger is still hot enough to re-warm the supply air plenum and thus the fan limit switch sensor even if the burner is off.

If the problem seems recurrent and random and not related to the end of a heating cycle I'd look for loose wires, fan-on wires from the thermostat shorted anywhere en route, or a bad control board (depending on your equipment).

You can rule out the thermostat wiring by disconnecting it entirely not at the thermostat end but at the furnace end.

Details are at FURNACE FAN CYCLES AFTER HEAT

We turn off the heat but the furnace fan never stops

With heat off, fan continues. How to stop fan? On 2016-04-03 by Robert

by (mod) re: blower won't stop running

Robert: searching InspectApedia.com for BLOWER FAN WON'T STOP yields this diagnostic article

https://InspectAPedia.com/heat/Furnace_Fan_Wont_Stop.php

let me kinow if you need further help.

Electric Heat Won't Stop Running FAQs

Electric baseboard heater won't turn off

I have a eletriric basebroad with low voltage themostat that the heat won,t shut off . I have replace thermostat. Could in be the step down tranformer or what should be my next step ,Thanks for any help -

by (mod) - Watch out for a shorted wire in the electric heat control - unsafe!

Arthur

Watch out: turn off the heater at the electrical panel. There is risk of a building or electrical fire.

It sounds as if there's a shorted wire in the electric heat control - try disconnecting the control wires first.

If you have a low voltage thermostat controlling an electric baseboard heater than that thermostat must be wired to a switching relay that turns the 120VAC or240VAC heater itself on and off. If that's the case the problem could be a failed relay.

Bar heater on the wall won't turn off and the cord is jammed

A bar heater on a wall won't turn off. Cord jammed On 2017-07-23 by Helen Elliott

Reply by (mod) -

Watch out: You need to unplug the heater immediately for safety. If you are physically unable to unplug the heater then you need to turn off the circuit that supplies that heater and have an electrician replace they receptacle end or cord connection.

Boiler (Hot Water or Steam) Heat Won't Stop FAQs

Help with thermostat - zone valve control that is not closing

Having an issue with my thermostat/zone valve.

I was getting heat to a zone when that zone was off. I replaced the 24v motor to that zone valve because after troubleshooting I realized the valve would not open all the way when asked and it would stay open slightly, causing the hot water heat to flow to that zone when the other 2 zones were on.

After installing the new motor and setting the temperature for that zone 5 degrees above the actual room temperature, the valve opened 100%.

I was happy to see that the valve now opens and closes properly. The old motor did not offer enough tourque to open fully. Well the issue now is the circulator pump is not turning on for this zone. So what do you think it is?

I checked the 2 wires connected to the thermostat and the wires/screws are tight. (Dec 4, 2014) Dominick

Reply:

Nice work Dominick

Check that the end switch wires on the zone valve are calling for heat when the valve is fully opened.

Then see detailed and more extensive diagnosis and repair help

at HEAT WON'T TURN OFF

My baseboard heaters will not turn off in some rooms

Hi my baseboard heaters will not turn off in my kitchen or livingroom I have two in the livingroom.

One is not on. I'm guessing it's not workingm but the other one is on; I'm able to turn off the analog heat switches in the other room, but just not thoese two and it's very hot. please help On 2018-04-14 by Shawnda

by (mod) - why are the baseboards still hot

Shawnda

I think you need a heating service technician on site to check your thermostats and other heat delivery controls, as I don't have enough information in your note to givce a confident solution.

If you want to understand what's probably going on and also to be prepared to talk with your heating service technician,

be sure to read, in the HEAT WON'T TURN OFF article, the section titled

Why Are the Baseboards or Radiators Hot Even Though the Room Temperature is Higher than the Thermostat Setting?

If the thermostats are Off it's possible that a heating zone valve is stuck open

as we explain at ZONE VALVES, HEATING

or a check valve on the hot water heating piping is stuck open

as we explain at HEAT STUCK ON BY CONVECTION - basically, a check valve failure problem.

Why would removing a radiator make another radiator not turn off?

I live in a 40 yr old apartment with hot water heat.

My upstairs neighbor removed at least one radiator during a renovation. Meanwhile, one of my radiators has continued to run hot, even though the thermostat is turned off. I think the problem is due to his renovation.

The strata ordered and paid for a new zone regulator in my suite, which didn't help. So, is this just a coincidence and I suddenly need to replace that radiator, or will that even help?

I'm thinking it has something to do with my neighbor's renovation-----gravity----water flows down, etc. I'm not a plumber and I don't understand how all this works. Can you help me out with some info or advice? On 2016-04-07 by Cynthia Traugott

Reply by mod

Cynthia:

It'd be odd for the removal of a radiator on another floor to make your unit run hotter, unless there was some strange plumbing in your place. You need someone onsite to follow the pipes, find the controls and then see how your heating system works.

Meanwhile try closing the input valve on that hot radiator.

Even if the thermostat is clicked off our hot water baseboard heat stays on.

We have a Thermostat that controls all of the heat upstairs (4BR’s and a bathroom) It controls the heat in all rooms except one just fine.

In our BR, even if the thermostat is clicked off our heat stays on. The baseboards are always hot! (We heat our home with oil if that helps) Please help! Any suggestions would be greatly appreciated !On 2018-10-27 by Jenni -

Reply by (mod) -

Jenni

In HEAT WON'T TURN OFF take a look at the discussion of hot water heat circulating by convection from the boiler because a flow control check valve at the boiler is not working.

Peerless MI-05 boiler troubles blamed on the U.S. President?

I have a Peerless MI-05. The unit will run periodically when the room temperature is above the thermostat setting. The unit will also run when the thermostat is set to "off." It will turn on and fin every twenty minutes, for about three minutes.

The contractor that installed the unit blamed the problem on federal regulations and, eventually, the President of the United States. Could it be a fault other than the President's? (Apr 3, 2014) John

Reply:

John,

I'd start by disconnecting the thermostat wires at the boiler end. That will rule out a wire short that an cause the problem you describe. I've also seen this problem as an artifact of the primary aquastat. It's a potential for a fist-fight that's to be avoided IMO.

If you read the installation instructions for a Honeywell aquastat (like the R818x series) you'll see that the mfg wants you to use a heat conducting paste on the sensor when it's mounted in the sensor well on the boiler = thus assuring good thermal contact between the aquastat's temperature sensor and actual boiler temperature.

The fellows like to skip this extra work and worse, will be very reluctant to go back and correct it as you'd have to R&R the whole assembly from the boiler in most cases. But that too could be at fault.

John also check the Aquastat settings.

John said:
Dan,
Thank you for your reply. This unit was installed in February of this year. I have no experience with this type of equipment.

It is safe to say that the unit is not working properly and we can rule out new federal regulations that require it to run as it does?

The contractor is begging for a political debate when I just want the boiler to work properly. Thank you very much for your help!

Reply:

If you are not already speaking with the company's service manager, give that person a polite call and ask for help from someone more experienced. If there is no higher authority you're stuck with the guy you have or bailing and hiring someone else. Sorry.

Our Heat Won't Turn Off FAQs

Tip: See the easy diagnostic and repair steps at HEAT WON'T TURN OFF

What do I do if my heat won't stop running?

Heater will not shut down - On 2017-02-20 by Duane

by (mod) - what about a thermostat that won't turn off: different articles

You will find two good diagnosis and repair articles for heat that will not shut down:

THERMOSTAT WON'T TURN OFF

and

HEAT WON'T TURN OFF

and if your heat is a furnace system (forced air) and the blower won't turn off,

see FAN WONT STOP - LIMIT SWITCH

Our heat won't turn off and we think it's in the electrical panel

I had Honeywell RTH6400D 24V thermostat which I was using for heat only on two wires. Before that was old manual with mercury but working well but I changed for cosmetic reasons after consulting Honeywell.

After 5 years this Honeywell RTH6400D thermostat was not turning off at set temperature and running continuously sometimes resulting in heating up of fuses in the main electric panel so to stop it we had to pull the fuse box out to cool down and put it back to start the thermostat again.

Before it was working good for one or two days after reset and then keep heat on continuously so we had to reset again by removing fuses.

We talked to Honeywell and they suggested new model RTH 111B but it also started behaving the same way which means the problem is not with the thermostat but somewhere in the thermostat transformer on the electric panel I don't know. Please provide some solution. Thank you. On 2018-01-19 by cooldeep

by (mod) - heat not turning off is not liklely to be the low voltage transformer

Cool

The problem with heat not turning off is not liklely to be the low voltage transformer (though you should verify its voltage output)

What happens when the heat won't turn off if you

1. Disconnect wires from the thermostat AT THE THERMOSTAT on the wall?

2. Disconnect the thermostat wires at the other end of their circuit, AT THE HEATING SYSTEM?

Those steps will rule out shorted thermostat wires.

Other possible causes of the problem you describe are in the article HEAT WON'T TURN OFF

Landlord has tenant who complains heat won't go down

I am very grateful for my landlord its very hot in here we have radiator s they should all have a leavle to shut off (Oct 4, 2014) Anonymous

I have a tenant who is complaining that the heat will not go down even though the thermostat has been at its lowest setting. I have gone there twice and both times, the pipes after the zone valve feel room temperature, but the thermostat is still showing the room is at 75. (Dec 14, 2014) Anonymous said:

I took off the baseboard covers and showed her how the pipes are room temp and immediately get boiling hot when the thermostat calls for heat.

My question is, could there be a tiny amount of hot water sneaking past the zone valve that almost doesn't register as hot when you touch the pipes, but still warm enough to keep heating the room? It's probably been averaging 20s-30s here in Minnesota lately.

She's on a third floor with units above below and on either side, but I can't imagine the residual heat from those units would heat hers to 75. I used to live there, but don't recall this problem.

Any help is appreciated.

Reply:

If the room temp is high, say 75F, indeed I'd expect the baseboard to be close to that temp even if there is no call for heat.

You might be seeing some convection circulation if a flow control valve at the boiler is not fully closing when the circulator is off, or if a zone valve is not fully closing.

But I'd look for

- improper thermostat settings
- a bad thermostat location - in a draft for example
- a dust or debris clogged thermostat sensor