# Comfortmaker furnace won't turn on



## steelframe8459

I have a early 90's Comfortmaker condensing furnace, and periodically it won't fire up, especially if the furnace has been off for awhile ie: in the morning after being shut down to a lower tempature.
The exhaust blower will turn on but the burner will not fire up.
the only way i can the burner to turn on is to turn the switch on the side of the furnace off for a few seconds and then back on, then it will light.
Does anyone have any thoughts on whats causing this.
Any info would be greatly appreciated. 


Thanks


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## kins

Hi steelframe, i have a Honeywell about the same year as your Comfortmaker and it is doing the same thing. I just had repairman out and he said there is possibly a blockage in the heat exchanger. What is happening with your heater since your last post? I would love to know what i am in for.


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## fixit50

Before reseting the furnace, what does the little red light do? how many blinks? I can help ya out


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## rabadger

to Kins: Honeywell does not make a furnace.
to stealframe: There was a manufacturer from that period that was having problems with the spark ignition locking out. The only way to solve the problem was to reset the internal lock out timing by turning off the equipment at the switch on the side of the furnace. I think the number was a SP750 controller but I may be mistaken. As a matter for fact I think more than one manufacturer had the problem. The problem may not be caused by a bad controller. Other things could cause it also. get a good service tech. Not a parts changer.


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## Combat Commander

I'm having the same problem with a Comfortmaker EnviroPlus 90


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## Smith2365

I too am having the same problem with a Comfortmaker EnviroPlus 90. I followed steelframe's instructions and got the furnace lit.


Does anyone know how this issue is fixed permanently? I am thinking of contacting Comfortmaker directly to discuss.


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## mas6132

*Fixit50*

Can you tell me how to fix mine COMFORTMAKER ENVIRO PLUS 90 - the furnace will not kick on and the red light blinks 3 times. Something about a PRESSURE SWITCH is OPEN at least that it what the panel of warnings says. How can I fix this. It is starting to get cold in St. Louis and wife needs heat on for the children. Can you help me get this fixed - as quick as possible? Also sent you an email.



fixit50 said:


> Before reseting the furnace, what does the little red light do? how many blinks? I can help ya out


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## AAMJV

*Comfortmaker EnviroPlus 90 furnace won't turn on.*

I have the exact same problem as mas6132. A repairman came in and pulled the exhaust fan end of the hose that runs from the pressure switch to the exhaust fan. He snipped off about 1/4 - 1/2 inch off the hose, and attached the hose back onto the exhaust fan and it worked. He said that worked in about 90% of these cases. Good luck.


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## sailn2horizon

Must read ***Disclaimer: This is the sharing of the experience of a unlicensed, unregistered, non-certified homeowner. The writer is not responsible for an incorrect information. Any reader of this post is taking matters into his or her own hands. The writer of this post is not legally or financially liable for any and all results or consequences of the readers action.***

The trickiest part to any repair to this furnace is to diagnose what is wrong with this unit. Typically, the Flashes through the window panel will give you some clue. If you have any doubt of your abilities, it is always prudent and safe to seek professionally certified service repair persons.

Over the past couple of years, this is what I learned. Please read in entirety first before taking making any decisions or taking any action of any kind. If you smell gas or see electrical sparks at any point, stop immediately and follow your local emergency protocal for gas furnace emergencies.

Single Flash:

1. Gas won't ignite therefore no heat is generated despite a reboot. Rebooting sequence is on the label of the unit where temperature is lowered on the thermostat, electrical power is switched off, at the gas valve (http://www.white-rodgers.com/pdfs/04_Cat_pages/04_Cat_pg_063.pdf), turn gas intake to off position, wait 5 minutes, turn gas intake to on position, switch electrical power to furnace to on, move thermostat to slightly above room temperature. 

As soon as the thermostat is set to above room temperature by a 1-4 degrees, the unit should start the induction fan, you should get 3-5 firing sequences by hearing clicks and small trace amounts of natural gas and the heat jets should kick in with the main fan to follow. If the heat jets don't kick in, the chances are your "hot surface igniter" went bad which is what ignites the gas mixture that heats the air output. This can be replaced easily and cheaply if you are handy for under $50 for the part at any well stocked hardware store or from a dealer/service outlet. (http://southsidecontrol.com/acatalog/Products_Igniters_Direct_Universal_HSI_1804.html). You should also take a steal wool and try to file down any residue on the gas jet sensor. Both of these parts are located just about the heat jets. The igniter to the right back corner and pointing towards the back of the unit and the sensor towards the front left and pointing downward towards the jet. Make sure when putting the igniter back in, it must be aligned properly with the gas mixture flow, otherwise, misalignment will not cause gases to ignite.

Try the reboot sequence again and the gas should light and you should feel the heat from the jets after the orange glow (heating of the igniter). If not, it's the wrong diagnosis and better call the service man.

2. Same scenario where no heat is generated and the jets won't ignite but the hot surface igniter is glowing orange in the same sequence. The chances are your gas valve went bad and is either not responding with the master board sequencing, the valve in the solenoid is not responding, or it's simply not allowing/pushing the appropriate gas mixture through to the jets. This is a tougher install and requires turning off the gas lead to the furnace after the power down sequence starting with the thermostat (see above). If you are a very good plumber and have reasonable electrical skills, you may want to attempt it, but I called a certified technician because I live in a condo. This way I don't violate any building codes, insurance policy due to faulty maintenance, warranties or simply put, put lives and property in danger.

Good luck to all and may your winters be warm and the cost of home heating be low.

Take care and please be careful. Enjoy the DIY task but most importantly be safe and protect yourself and property. ***Disclaimer: These are simply posts of an unlicensed uncertified and non-professional home owner sharing his experience and should not be taken as professional and legalling binding advice for any and all repairs. Readers of this post is taking matters into his or her own hands and the writer is not liable for any and all damages or consequences as a result.


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## mas6132

FIXIT50 -

Hi! It is Mike again with the Envro Plus 90 - giving me the same problem again 2006. Again the thermostat tells the furnace to kick on, the blower unit starts up and then continues to run - eventually timing out. The red light is flashing three times. I have tried to take the panels off and replace them hoping to make sure that everything is shut properly - but still luck. Can you help me out! Again, it is starting to get cold in the evenings.


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## #CARRIERMAN

Hi mas6132

I am assuming that you have not had a proffesional tech look at your furnace. Every piece of equipment that has electronic ignition on it has certain safetys built into them. What causes igniton failure is poor maintenance practices. Probably all that is wrong with your furnace is either it has a pilot that needs to be pulled and cleaned that uses a flame sensor that also needs cleaned. Or it is hot surface ignition and need the flame sensor pulled and cleaned. If you are mechanically inclined this is not a difficult task. Turn the power off to the furnace or unplug it whatever is available to you. Remove the burner acess cover, locate the stainless steel rod that is about 3/16" in diameter. Remove this rod and clean it with a wire brush, do not use sand paper !!!!. Once you have done all this reinstall the rod, start the furnace backup and see what happens. If this problem has been let go for too long you may have to repalce the ignition control. It could have burned the flame rectification circuit out of it. After you get all this done, find and HVAC company in your area that is reputable. Buy a service contract with them and let it become their headache.

Good Luck
Rusty


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## camcdole

*Where is this little red light?*

I have a comfortmaker model GNJ075N12A1 and it just won't heat. The thing "kicks on" at the right temp but no heat. I have turned it on and off sevral times and no cigar. Am I missing something?


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## Justin1635

good god, i am so glad im not in residential 


it seems like you all need to go through your furnaces, give them some tlc. browse this forum for all the info you need


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## DFANG35

I would like this question answered also. When I turn my furnace on the red light blinks 1 time which shows it's in lock out. What can I do.MY furnace comes on and blows warm for sometimes a couple of hours and sometimes for several hours. I have replaced the inducer motor recently because that's what I was told to do. I was hoping that would remedie my problem. Can someone please give me some insight as to what I can do to fix this problem permanently.


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## sunlzrd

*somfortmaker pressure switch not available*



camcdole said:


> I have a comfortmaker model GNJ075N12A1 and it just won't heat. The thing "kicks on" at the right temp but no heat. I have turned it on and off sevral times and no cigar. Am I missing something?


I have a comfortmaker model same as yours and my light blinked 6x. No such thing so my tech installed a new one. Then it blinked 2x. Means I ned a pressure switch. Comfortmaker no longer makes a pressure switch for my 96 furnace. Ive been through 3 switches that my tech has installed over the last month. Yes its cold. I've talked to everyone at ICP. My next furnace will NOT be a comfortmaker. Why would a company make something to last 20 years but quit making the internal parts after 5 years. I'm not trying to fix my furnace myself,,,,,,,I'm just trying to get some heat without having to manually re-wiring it everytime I want heat. Anyone out there that can help? I've already paid my tech 5oo.oo and still no heat.Help!!!!!


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## rakes9720

Any pressure switch with the same pressure setting as the original will work. And if the tech has been replacing pressure switches every time this error comes up, its time for a new tech. A pressure switch is a safety switch; if it is not "switching", then it is doing its job. You probably have a blocked vent or a bad inducer motor or wheel. If you are bypassing the pressure switch, you could be allowing gasses to enter your home and they could kill you!
Find a different serviceman, and tell him to clean the vent, heat exchangers, or replace the inducer.


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## sunlzrd

*Thanks,rakes9720.*

Thanks so much for the input. I will definitely have to get a new tech. I hope the next one will know what to do. It seems like there are alot of problems with the 90's Comfortmakers. Too bad you don't live in Atl and I could pay you to fix it. You have given me more info than any one. Thanks again for you help. Sunlzrd


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## gamblinman

*Same problem here*



steelframe8459 said:


> I have a early 90's Comfortmaker condensing furnace, and periodically it won't fire up, especially if the furnace has been off for awhile ie: in the morning after being shut down to a lower tempature.
> The exhaust blower will turn on but the burner will not fire up.
> the only way i can the burner to turn on is to turn the switch on the side of the furnace off for a few seconds and then back on, then it will light.
> Does anyone have any thoughts on whats causing this.
> Any info would be greatly appreciated.
> 
> 
> Thanks


I found by removing the plastic box on top of the gas valve and flipping it over that theres a bad soldered connection on one of the resistors ends, problem is I haven't found anyone who will sell this part of the gas valve and the last time I replace it , it cost me $500.00 2 years ago. I found the whole valve for $350.00 but this furnace is costing an arm and a leg to keep it running every 2 years then. I'd resolder the connections but the board shows slight signs of being burnt from arcing and trying to open the gas valve. Hope you had better results than I'm having.
Gamblinman


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## MrsT

*Advice please.*

My daughter has the same Comfortmaker model GNJ075N12A1 made in 1995, installed in 1996. My husband could get it lit by blowing across the gas vent when the ceramic heater lit up, however since I had the HVAC guy come yesterday, we can't even get it to do that. I asked him to check the gas pressure and the vent--which he did not do. He only switched out the part that glows (igniter?), and it still wouldn't work. This cost me 2 hours of service, and I had to buy 3 space heaters. He said it could only be the control board and the whole inside of the furnace had to be rewired because the old parts were no longer made. The estimate is $577, and I have another company coming today. My husband wants to buy a new furnace, but that would mean a whole new system, and I love the AC--her bills are always below $100/month in the summer. My question is: I replaced the filter with a new 3M filter. Could this be interfering with the draft? Should I buy a cheaper filter? Maybe the exhaust fan doesn't have enough draft with the 3M filter? Could there be a bird's nest in the flue? Her water intake pipe to the house has had to be dug up twice in two years for tree roots(same house corner)--should I be calling the gas company? Yes the trees are gone.


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## Billiam67

*Comfortmaker furnace firing issues*

I have a FBF050B12G Comfortmaker furnace that is not maintaining fuel to the burners. I have found by accident, even after a service tech was out and changed the burner solenoid, that the *Pressure Switch line* from the pressure switch to the combustion burner is filling up with water due to condensation. About every day and a half I need to pull the line off one end and dump the water out of the line. This fixes the issue temporarily.

What I need to figure out now is why this is happening. I do not use a humidifier in my system. The basic, and I mean basic, manuals that I can find on line do not indicate if there is a drain line anywhere. Any ideas?:whistling2:


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## beenthere

Yea, it doesn't have to be a pressure switch from IP.

Your tech, is a tech, he's a parts changer.
A real tech would look to see why the switch isn't closing.

They make adjustable pressure switches to replace OEM switches.


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## Billiam67

The adjustable pressure switches to replace OEM switches, what will this do? I think I need to focus on the water issue in the line. Luckly the "service part changer" did not take me to the cleaners.


Thanks for the input.


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## SKIP4661

Can you say profitmaker?


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## beenthere

You adjust it to the pressure setting that the OEM switch was.

It saves having to carry 50 different switches.
Or having to order the OEM in.

No reason to make a customer wait till the next day for heat.
Just because of a pressure switch.

But, your tech needs to find what is really wrong. A pressure switch is a safety device.
Its probably doing its job, and saving your life.


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## hvaclover

No one has mentioned the problem that causes all these symptoms on a ICP
furnace.

There is a combustion ring that the inducer draws air thru. The inducer has this combustion ring mounted to it's air intake. This could be either slipped out of position or be gone completely.

And to complicate the matters, it does not come with a new inducer. Has to be bought separately.

No ring, misfires and all the things that the posters have mentioned.


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## HotAmNot

*Comfortmaker starts, fires up, then turns off in seconds*

I have a Comfortmaker, model GUD040A012AIM, and there was definitely an igniter problem as the igniter did not glow. I replaced it, and now it does glow, the gas does ignite, but for only 1-2 seconds, then shuts off. The red light on the controller flashes continuously after it goes out.

I at least know that the gas is working. There is a flame and the igniter works, but I cannot figure out why the main blower does not come on, or when the flame is quickly extinguished?

Any clues


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## HotAmNot

I read the post by FixIt50, and it is very helpful, except he does not mention this scenario where both the igniter lights AND the gas comes on.

Contrary to my earlier report the red light is now only flashing once at the start of the ignition process, when the thermostat triggers the furnace to turn on. All goes well, except the gas goes off after about 1-2 second of burning, so the relay does start the igniter, which does light the gas.

Once it turns off, there is no flashing light sequence.


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## bloom42

I too have the same problem. The combustion fan will kick on, igniter will glow but the pilot light will not ignite, thereby not heating the sensor to turn on the burner. It works sometimes but not all the time. I can manually start by removing the combustion chamber cover and, using a long handles lighter, put a spark in front of the pilot light. That will light the pilot and get it working. I will try and wire brush the sensor as suggested by #CARRIERMAN and checking the pilot orifice for deposits and will post again afterward.


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## handy man88

MrsT said:


> My daughter has the same Comfortmaker model GNJ075N12A1 made in 1995, installed in 1996. My husband could get it lit by blowing across the gas vent when the ceramic heater lit up, however since I had the HVAC guy come yesterday, we can't even get it to do that. I asked him to check the gas pressure and the vent--which he did not do. He only switched out the part that glows (igniter?), and it still wouldn't work. This cost me 2 hours of service, and I had to buy 3 space heaters. He said it could only be the control board and the whole inside of the furnace had to be rewired because the old parts were no longer made. The estimate is $577, and I have another company coming today. My husband wants to buy a new furnace, but that would mean a whole new system, and I love the AC--her bills are always below $100/month in the summer. My question is: I replaced the filter with a new 3M filter. Could this be interfering with the draft? Should I buy a cheaper filter? Maybe the exhaust fan doesn't have enough draft with the 3M filter? Could there be a bird's nest in the flue? Her water intake pipe to the house has had to be dug up twice in two years for tree roots(same house corner)--should I be calling the gas company? Yes the trees are gone.


I wonder how a bird's nest can be in the flue.

Wouldn't the bird die from direct and continuous exposure to CO?

Also, would an HVAC or plumber be appropriate for maintaining or checking a flue to make sure it's not blocked? Does anyone know?


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## bloom42

Ok, I the pilot orifice is ok. I unscrewed the ignitor/sensor/pilot assembly, removed the clip holding on the ignitor/sensor, turned on the furnace and held it infront of the pilot light. The ignitor was red hot and the gas was flowing but the ignitor would not ignite the pilot no matter where it was. I put a spark from a lighter infront of the pilot and it lite right up. The pilot flame was good and within the spec range stated in the tech support manual.

FYI - this is a replacement ignitor/sensor (MM-643KJ NITRD IGN ASSMB) which is different than the original (P/N 1009524 for a NUGM/GUK Series furnace), supposidly better. The original one burn out/quit working. I think I have to pony up and spend more money for the original type. Any ideas from anyone before I spent the $$?


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## bloom42

I replaced the nitride igniter assembly with the OEM carbon type and the problem has been solved!!! Happy Day, and it was free to boot because the one that was failing was less than a year old.


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## shocker9799

I am a HVAC service tech, the most common problem is the furnaces have not been serviced, you probably have a dirty flame sensor, you could also have a blocked drain. Just keep this one simple thought in mind: Do you wait till your car breaks down to do an oil change, or tune-up, WHY would you do it with the most important appliance in your home???


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## BHanson

Similiar problem with intermittent operation.....works then blows cold air continually (blower never turns off (lockout). Does not respond to "off" at thermostat. Unit will turn off by shuting power off at the unit and lights normally when switch is cycled back on. Works most of the day but eventually repeats this malfunction. After changing the igniter, cleaning the flame sensor, cleaning the air filters and checking for proper airflow through the air vents (a check for a blocked/dirty heat exchanger) I finally narrowed it down to the high limit switch (this as a safety device which shuts down the burner if the ducts exceed a given temperature) I bypassed the switch by jumping the wires and the furnance has been working fine.now for several days. I will try to get a switch locally and will pass on the results. Remember...this is a safety item and shouln't be bypassed unless somebody can monitor the furnace operation. I would recommend setting the themostat on a comfortable temperature or if programable set the temp on "hold" and see what happens. Don't keep playing with the thermostat


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## beenthere

That switch doesn't go bad. Unless something is causing it to open. So I would advise you stop running it without that limit. As you have a problem with your furnace over heating.

Perhaps its just that you didn't change your air filter for several month. or it may be something more severe. Find out now, before you damage your heat exchanger, or worst.


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## hvaclover

Gotta disagree with you on that Been.

The small amount of limits i have changed thru a year have been from furnaces I know are free from over temp conditions cause I service them every winter.

My wholesalers probably agree cause when I come in to buy them they give them to me no charge. The construction of the bi metals are not equal to the job of normal furnace operation.

I don't think it should surprise any one when we have five amps of current draw from the HSI going thru a metal disc less than dime size it going to go relatively quickly as compared to limits with more surface area.

Just recently Nordyne went to a flush mount snap disc limit. ICP as been using the larger snap disc to great effect for over seven years now.


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## dnice

Same here but my RPJ II responds to thermostat when I lower it 1 degree or shut off for few minutes then restart. LED flahes 1 time. Flame sensor already cleaned and new clean filter. Tech said you need a new heater !!!!!!!! Any thoughts ??


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## beenthere

Please don't hi jack other people's threads. You will get an answer to your question in your own thread you already have started. need to give people time to get home from their jobs, so they can answer you.


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