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steelframe8459 01-27-2005 12:54 PM

Comfortmaker furnace won't turn on
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.


kins 02-08-2005 05:39 PM

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.

fixit50 02-20-2005 06:10 PM

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

rabadger 02-24-2005 06:03 PM

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.

Combat Commander 10-10-2005 08:29 PM

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

Smith2365 10-27-2005 07:54 AM

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.

mas6132 11-17-2005 01:11 AM

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.


Originally Posted by fixit50
Before reseting the furnace, what does the little red light do? how many blinks? I can help ya out

AAMJV 12-03-2005 01:35 PM

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.

sailn2horizon 01-02-2006 03:28 PM

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 (, 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. ( 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.

mas6132 11-12-2006 01:16 PM


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.

#CARRIERMAN 11-12-2006 03:49 PM

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

camcdole 11-16-2006 03:51 PM

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?

Justin1635 11-16-2006 11:04 PM

good god, i am so glad im not in residential :mad:

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

DFANG35 11-21-2006 10:11 PM

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.:eek: 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.

sunlzrd 02-20-2007 07:19 PM

somfortmaker pressure switch not available

Originally Posted by camcdole (Post 23881)
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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