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Kenton Guidry
Kenton Guidry, HVAC Technician
Category: HVAC
Satisfied Customers: 966
Experience:  12 years install/service experience.
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Why does my Coleman Evcon gas furnace kick on and off?

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My Coleman Evcon gas furnace kicks on for about a minute and then kicks back off. I can see the pilot "element" heat up, then the gas fires up, however the gas shuts off after about 15 seconds. Thank you in advance.

I have seen this type of problem happen before and it ended up being the pressure switch for the induce draft fan. Would you be able to jump the pressure switch?

Customer: replied 8 years ago.
Hello Kenton. I am willing to try, though I do not know how to proceed. Where is the pressure switch located and how do I jump it?

The pressure switch will have a tube attached to it which runs from the pressure switch to combustion fan. it should also have two wires running to it. How familiar are you with electricity?

Customer: replied 8 years ago.

I believe that I have found the pressure switch. I am somewhat familiar with electricity.

You also may try accessing the ignition control to see if you have any led indications. There are only so many things that can do what is happening to your unit. If you had a meter to test for an open or closed circuit you would be able to find your problem easier.
Customer: replied 8 years ago.


How do I jump the switch?

by touching the wires together. be careful not to hurt yourself. if this is the problem the unit should stay on.
Customer: replied 8 years ago.
There are two wires which both have a flat, slide-on attachment at the end. I removed those two wires and touched them together. Nothing seemed to happen. I did not see a spark, hear a noise or otherwise observe a change. Did I do something incorrect?

I normally use a jumper wire between them so that I can reset the unit and fire it off again. You would not see a spark. Do you own an electrical meter? If you own a meter. You can test each saftey circuit to see which one is open. Also if you can access the ignition control, they sometimes have a blinking light with a code that can be looked up.

Customer: replied 8 years ago.

I don't know if this is relevant, but we received about a foot of snow last night.

In regards to your post about an LED indicator, there is a small silver box above the pressure switch. There is a small window through which I can see a small green LED that is solid. On the top of this box is a diagram for wiring. On the diagram it gives an indication as to diagnostic codes, flashes and fault conditions. If I am reading this correctly and the small green LED is the corresponding indicator, the system shows normal.

Above that area is another box, this one tan, that says Deluxe Blend Air II. It has two switches, one for Alarm and the other for Fresh Air. I believe it is for Central Air Conditioning, which we have never used. The Alarm switch is in the off position and the Fresh Air is in the on position. There are three small LED indicators on this box as well. A yellow one on the bottom (off unless I turn the Alarm swich on, which also begins a beeping sound), a green one (on and solid) and a red one on top (flashing). There is a warning that if the alarm is sounding and the red light is flashing there is a problem with the attic fan and to call for service.

Does any of this help?

Customer: replied 8 years ago.
Sorry didn't see your post until after I sent the most recent. Where are the safety circuits? I have an ohm meter I believe.
Customer: replied 8 years ago.

I have a multi-meter.

I found an article on the Delux Blend Air at this link.

I am reading throught it now to see if I can find any helpfull info.

Customer: replied 8 years ago.
Thank you.

* On the Deluxe Control Box, a lit amber lig ht indicates that the damper is open.
* A lit green light indicates that the attic fan is running.
* A flashing red light indicates that the attic fan is not running.

According to this information, can you tell me which lights are on.

Hey Customer- Is your blower motor ever kicking on after the burners fire?? The burners will fire for about 15-20 seconds to warm the heat exchanger before the limit switch brings the fan on, so you will not be blowing cold air into your house while you are calling for heat. if for some reason your fan is not coming on, (defective capacitor, defective motor, defective circuit board, defective limit switch) this would definately be the best answer to the description of your problem. kenton is correct about the flame sensor. it would shut the gas off way before 15 seconds if that was the problem. but Rick is also right in the fact that you would never get ignition if the pressure switch was the problem. these furnaces have a sequence of operations they have to go through and the presssure switch has to be proven beofre the gas valve is ever allowed to open. your problem seems to be with the blower motor or the high limit or the draft limit. not trying to say the other experts are wrong, but i feel you are checking things that arent the source of your problem.
Customer: replied 8 years ago.


After switching the alarm switch on, I have a flashing red, a solid green and a solid amber.

Customer: replied 8 years ago.
The blower motor is engaging both before the "fire" and continuing until after the "fire" is out.

Can you use your meter and test your pressure switch, high temperature limit for a closed circuit?

Kenton Guidry, HVAC Technician
Category: HVAC
Satisfied Customers: 966
Experience: 12 years install/service experience.
Kenton Guidry and other HVAC Specialists are ready to help you
Customer: replied 8 years ago.
Sorry for my ignorance, but how do I test for a closed circuit using the meter?
Customer- I am sorry I wish I were more help. I am going to opt out so someone can jump in and get you taken care of. You normally put the meter on ohms and put a lead on each side of the sensor. My meter makes noise when I have a closed connection.
Customer: replied 8 years ago.


Thank you for your help, I really appreciate it. Sorry for being so dense!

so you said your blower motor is running after the burners fire??
r u there??
Customer: replied 8 years ago.

Hello Josh.

No, I was mistaken. It appears that as soon as the blower kicks on, the fire goes out.

If I tested for a closed circuit correctly, I did not hear a noise and there was not anything on the display either.

Customer: replied 8 years ago.

Sorry, I was watching and waiting on the furnace.

While the blower was running, the element came back on, though directly before the burners fired, the blower turned off. The burners were on for about 30 seconds, though as soon as the blower came on, the burners went off.

just want to verify that the blower motor is the blower in the bottom of the furnace. the inducer motor is at the top of the furnace by the vent. let's unplug the furnace and start all over. unplug the furnace, wait 5 to 10 seconds and then plug it back in, make the thermostat cal for heat and tell me exactly what happens.
HI! Sorry it seems like all the newbies are jumping in on our question they shouldnt be doing that and I apologize for them. I just didnt want to be rude too and really confuse you with what they are also saying so let me know who you would like to finish helping you Kent opted out for me to continue but illleave it up to you. Good luck.
Customer: replied 8 years ago.

Okay. Please stand by.

Customer: replied 8 years ago.
Sorry, it seems that everytime I post, I have to send it twice.
Customer: replied 8 years ago.

When I turned it off and then turned it back on, I increased the temperature on the thermostat. That turned on something towards the middle (I believe it may have been the inducer motor that you refered to). THen the element comes on. About 20 seconds later, the burners ignite. About 25 seconds after that, the blower comes on (it is at the top, in a silver cylindrical shaped piece of metal with "rotation" and an up-arrow stamped on it). As soon as the blower comes on, the fire goes out. After about 45 seconds, the element came on again. The burners fired and this time the blower continued, as well as the burners. The burners went off about 20 seconds later and the blower stopped after a total of about 2 minutes. About 2 minutes later, the blower came back on, though I did not see either the element or the burners light. The blower shut off after another couple of minutes.

Customer: replied 8 years ago.
Josh, are you still here?

i think you have a defective limit or a defective circuit board. sorry about the arguement between experts!! we are all qualified to be here or we would'nt be. it isn't professional to call other experts newbies in front of customers because they have less expericence than you. hope i helped you.

Customer: replied 8 years ago.

Sounds like I need to call a local service person to fix it then.

I understand with it being a public forum that there will be disagreements.

Thank you for your help.