Question about Heating & Cooling

1 Answer

Having a problem with my AC/Furnace. AC was working fine and was turned on for about 3 weeks. Thursday night it cooled off and we opened up until Saturday morning. On Saturday morning the AC would not turn on, neither would the furnace side. Furnace is a Janitrol GMP100-4, 14 yrs old. Checked all breakers and they were ok. Thermostat was calling for heating/cooling. Checked circuit board and 3 amp fuse was blown. Replaced fuse and it popped again. Called local HVAC guy since it was Saturday and hot and he came over and stated that the transformer was shot and replaced it. He also checked and recrimped connections for the thermostat wires. Afterwards, he checked the AC and furnace the furnace appeared to begin starting up, the element would light but NO burner activity. This would just continuous cycle like this. The outside AC unit would not kick on but the inside blower would start. He thought there was a short somewhere. Told me that problem could be 1 of 2 items, 1) bad thermostat since it was only sending 20V to unit instead of 26V or 2) thermostat wiring short between furnace and outside AC unit since he saw some gnawing in the garage from apparent mice activity. He advised me to check those two items to save some money. I was not real certain that he was on the right track or just confused. Today, I replaced the thermostat and ran a thermostat cable from the furnace down my hallway and through my garage doors right to the AC unit to test his theory, same issue. I see voltage of about 20 volts at the end of the wires. When I connect the wires, there shows 0 volts at the contactor connections. I also replaced the control board, no change. I did some measurements: 25 V or so from R to C 25 V or so from Y to C in cool mode 25 V or so from W to C in heat mode During heat cycle, red light on board stays on solid, unit attempts to start, igniter glows but no burner action. This happens 3 times then unit goes quiet. Gas valves and control appears ON. I never get 24 Volts at the Gas valve. The transformer output jumps around and does not stay a solid voltage. During cool cycle, exterior unit does not kick on. Could the transformer be bad that he installed? Could he have wired the transformer wrong to cause both of these problem? If so, how do I correct without bringing him back? Any suggestions?

Posted by on


1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert who has answered 20 questions.


    An expert that hasĀ over 10 points.


    An expert whose answer gotĀ voted for 2 times.

  • Expert
  • 60 Answers

I think your problem is poor usage of the device,i.e. overloading the system. try running better cables to your furnace and ac. The reason i am lead to believe that is. If you already hired a pro to come and fix it for you,and he/she could'nt then what else could it be? in my experience ac units use electricity like microwave ovens.and power tools

Posted on Sep 12, 2009


1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


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



Related Questions:

1 Answer

I have a goodman furnace that was installer 2 weeks ago. It ran fine until it blew a 3 amp fuse this morning. It works fine as long as I do not have anything plugged into the Com terminal.

c is your common, u only use it if you have ac, humidifier, or u use 24 volts for t- stat, follow the common wire and see what it feeds u do not net it for heat, could be ur ac or humidifier has a short in it

Dec 20, 2015 | Goodman Heating & Cooling

1 Answer

I have a Dometic RM2652RBX Refer. The last two trips out it has given us problems. The first trip it worked fine all the way to Texas. We spent 2 weeks in Texas with no problems. We went to the Grand...

If the RV was level when it did not function. First you will want to open the rear vent of the fridge on the RV and check for a yellow residue above the burner area. If you do see that, then you will require a replacement cooling unit because the pipe ruptured. It is common in all new RV fridges that the cooling units lets go within 3 to 7 years. Check out ArctiCold Refrigeration We keep it cold the replacement cooling unit can be purchased through Ebay Dometic RM2652 Brand New Manufactured Cooling Units LIFETIME WARRANTY

Sep 17, 2013 | Dometic RM2652 Refrigerator

1 Answer

AC furnace huming

Blower motor & or capacitor bad

Jul 10, 2013 | Heating & Cooling

1 Answer

My A/C was serviced last week and it was fine until last night when the cooling is not enough again

To get proper cool, keep the tips as follows:
1. Check air filter is cleaned. 2. Check indoor coil is cleaned. 3. Checkindoor blower motor is working. 4. Keep in cool mode. 5. Set temp minimum 3degrees less than room temp.6.Check compressor is working with correctpressure.
Thanks. Helpful?

Jan 15, 2011 | LG Heating & Cooling

1 Answer

AC unit turns on blower doesn't come on

The thermostat is the controller.

Jun 19, 2009 | Heating & Cooling

1 Answer

2 weeks ago one of my units stopped working properly. It got warm during the night even though I heard the unit running. I shut it off and called for repair service. They changed the thermostat and it...

sounds like the coils inside the air handler/furnace are freezing up. likely cause is the freon charge is incorrect (probably undercharged). it may have been correct when the tech did the work but some may have leaked out. it is slightly possible too that the system is overcharged. you should have the system pressure verified, and then have it checked for leaks.

Jun 16, 2009 | Goodman CLJ36AR42 Air Conditioner

1 Answer

The furnace is blowing warm air even if the thermostat low.

The only thing that tells the unit to come on and off is the thermostat so I would definatly say it is it. When you turn the system back on, does the a/c run normally? If it does, then it's the problem with the heating side of the tstat. Also, does the fan come on when you put it to on and then turn of when you switch it back to auto? If it does, then the system is working fine, its the t-stat. Let me know if you have any more problems.

Mar 23, 2009 | Intertherm P3RA-048K Air Conditioner

1 Answer

Amana Range ARG7300W -- igniter problem back??

I am sure you noticed where it is located. A gas oven cycles the same as an electric. depending on the number of times the door is opened and the length of time you operator the oven. Our furnace was acting up one night last winter and I turned the oven on warm with the door cracked open until I could get the part for the furnace in the morning and our igniter went out on the oven. Also try not to touch the element on the igniter when you install the new one.

Dec 02, 2008 | Amana RanARG7302 Gas Kitchen Range

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

Related Topics:

220 people viewed this question

Ask a Question

Usually answered in minutes!

Top Heating & Cooling Experts

Paul Carew

Level 3 Expert

3315 Answers

Tim Whalen

Level 3 Expert

3074 Answers


Level 3 Expert

80668 Answers

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

Answer questions

Manuals & User Guides