Question about Honeywell Programmable Thermostat Heater

Open Question

Heil DC90 gas furnace need to find reset or limit switch

I have a heat exchanger problem and no money for repairs until Jan. Short term solution is to hit rest(limit) switch. Cannot locate switch.

Posted by on

2 Suggested Answers

Therinnaiguy
  • 1420 Answers

SOURCE: i have an older model heil quaker natural gas

Test to make sure the limit switch is still working prior to the rewire. Use an Ohm meter and test for continuity. If good, use some good quality 14 or 12 guage wire to rewire. If the unit has an in-line fuse, you will need to replace that as well.

Posted on Mar 27, 2010

  • 2364 Answers

SOURCE: I have a heil dc90 furnace wondering what the

lpg is 12 to 14 inches wc nat gas is 4 inches wc ,

Posted on Feb 02, 2011

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

Can you install class-A cotton foil-backed insulation in a furnace heat exchanger duct


HVAC Insulation Cotton thermo acoustic duct wrap reduces noise and increases HVAC...

None of these products are used INSIDE the heat exchanger. If the problem is a cracked heat exchanger, you may be able tp purchase replacement parts to repair it

How to Fix Cracked Furnace Heat Exchanger DoItYourself com


The heat exchanger must be free of cracks and holes due to the potential of carbon monoxide leakage. You can probably make a short term repair with sheet metal and high heat furnace refractory cement, but that is a quick fix only.
Please be aware of the potential for a lethal situation due to carbon monoxide poisoning.

May 26, 2014 | Cozy (W352E) Heater

2 Answers

Flame comes on, fan runs after a few minutes then unit will shut down, will sit a few minutes then sart back up, seems to be short cycling all happens within 8 minutes. \r\nmodel QVB-2505 PS. What...


there are limit sensors around fire box.you need to remove front cover.if flames are coming out of fire box there's a restriction in air flow. on older furnace could be fan belt . air cond. coil could be pluged up are all the vents open and have good air flow?you check limits by pulling one wire and check with ohm meter.there normally closed and open when too hot.most limits around fire box don't reset them selves.on some draft inducers there's a limit if it is tripping then theres a vent problem.theres also a limit on the fire box (heat exchanger) that may or may not self reset.

Jan 12, 2011 | General Heating & Cooling

1 Answer

Goodman dependable 92,7years old. Furnace works sometimes. Checked out by qualified technican. no problem found. Constant checks shows troubleshooting light blinks three (3) times. Help please. 3...


This indicates a open limit switch on the furnace, the heat exchanger is getting to hot therefore the limit switch is opening and not allowing the furnace to work properly. Did the techinician check the limit switch on the unit?

Dec 30, 2010 | Goodman GMS90703BXA Heater

1 Answer

PGB030075-1 Led light is blinking 4 quick blinks. blows out cold air. What does this mean?


4 blinks indicates a failure at the high limit switch. This switch is usually located on the heat exchanger face plate and has two wires going to it. Usually it fails because the furnace has over heated. The most common reasons are a plugged filter or coil that is limiting the airflow over the heat exchanger. Turn off the power to the furnace, replace the filter, clean any coils in the plenum and verify that all the vents in the home are open. Then turn the power back on and see if it is fixed. :)
If the above solution does not fix the problem, the limit switch itself may be bad from excessive heat. Replace it with a new one. Good Luck!

Dec 28, 2010 | Goodman GMS90703BXA Heater

1 Answer

I have a Lennox Whisper Heat that when a call for heat comes, the pilot lights as it should, then after about 30 seconds the blower fan comes on, then its about another minute before the burners light....


Yes it should go in this sequence, first exhaust fan, after establishing air flow you get a pilot, after signal from pilot is established you get main burners, then they have to reach a set temperature on the high limit and then the blower comes in. Now you have several over heat safety sensors one of them could be tripped check by powering the furnace down and see if they have a reset button on them, some do some do not. If not it should be the sensors closest to the heat exchanger and blower assembly use a volt ohm meter and check them should be normally open until temp is established then closed. This is easier done than it is to describe, now locate the high limit switch and bulb and see if it is open across the contacts it should be until it hits temp then it closes to start the blower. Hope this helps instead of confusing the hell out of you. Take your time locate the items then test.

Dec 19, 2010 | Heating & Cooling

1 Answer

One out of 5 or 6 times the heat exchanger will ignite and run about 60 seconds and the circulating fan will not come on.until the exhaust fan runs about 3 minutes and then it will energize


Need make and model number of unit. But sounds like a limit switch. Check filters and pull and clean limit. It is located above burner. Small square plate with two wires coming off it. Rus

Mar 17, 2010 | Heating & Cooling

2 Answers

Gas heater doesn't stay on longer than 5 minutes.


It sounds to me that your air flow is restricted somewhere. The first thing to check is your air filter. If that gets real dirty your restricted air flow will cause the hi-limit(hi temperature limit switch) in your heat exchanger compartment to over heat and open up your gas valve electrical circuit,thus, shutting off the gas to your burners. After the hi-limit switch cools down the furnace will go back to heating again then it will overheat again(you get the picture?) If it keeps cycling on and off like that the house will never get warm if it is cold outside. If your air filter is reasonably clean(you should be able to see light thru it easily) then the secondary heat exchanger could also be dirty, this is located above the indoor fan housing, you would need to pull the indoor blower assembly out of the furnace and look up above. The secondary heat exchanger looks similar to a radiator will fins. You can use a medium stiff plastic brush to brush the dirt,hair, whatever off of it. Another problem spot would be the cooling evaporator coil (if you have central airconditioning) located most likely above the furnace in the plenum(if your furnace is in a basement). This usually is difficult to access if an access cover wasn't installed when the airconditioning was installed. I would recommend an experience service tech to clean it for you. Also make sure all you supply air registers and return air registers are open . These are the things I would check first. Good luck!!

Nov 19, 2009 | Goodman GMS807034ANA Heater

1 Answer

I have a wall furnace whose fan short cycles on and off (even when the burner is still burning). I replaced the fan control switch, to no avail. Any Ideas?


Could the fan motor be heating up and shutting down on thermal overload? How long of a duration does it stay off before it starts again? Typically there is a bi-metal switch that rests on the heat exchanger and starts and stops the fan motor. If it is bad or not resting against the exchanger it will not operate as it should. Check the location of the switch. If it is touching but still cycling, test your switch with a multimeter set on Ohms. Let the heater run, jump the two wires you pulled off the switch (they are 120 volts so be careful) and watch your multimeter to see when the switch opens and closes. If it cycles as it has been, you have a bad motor. If the switch closes as the heat exchanger gets hot and stays hot as long as the heater is running, the switch is good.

Nov 06, 2009 | Heating & Cooling

1 Answer

A 1979 Colman RV furnace. Blower shuts off shortly after burner shuts off leaving a hot heat exchanger. After 15 seconds blower comes on again blows for 10 seconds shuts off comes on in 15 seconds blows...


The fan limiting switch is acting up. It should stay running until lower temp is reached. It will cycle until the temp stays below or at the low setting. Limit switches are adjustable.

Jun 09, 2009 | Coleman Propane Forced Air Heater...

Not finding what you are looking for?
Heating & Cooling Logo

Related Topics:

1,094 people viewed this question

Ask a Question

Usually answered in minutes!

Top Honeywell Heating & Cooling Experts

Bill Long

Level 3 Expert

587 Answers

paulcarew

Level 3 Expert

2364 Answers

Brandon Berry
Brandon Berry

Level 2 Expert

407 Answers

Are you a Honeywell Heating and Cooling Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...