Furnace runs, no heat

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  #1  
Old 10-29-07, 12:37 PM
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Furnace runs, no heat

My furnace, RPJ comformaster II, natural gas, forced air upflow, when it starts, the exahust fan kicks on, the ignitor starts the burner but then the burner goes out but the blower motor runs and blows non heated are thru the house. Some times the burner will relight and I will get heat and sometimes the burner will relight and go back out. Other times, the burner lights and stays lit and works normally.

At first, I thought the thermostat was bad cause it would get cold in the house and I would switch it off and back to auto and it would start but that is when I found out that the furnace starts but no hot air. I changed the thermostat and the same exact thing is happening. I traced the wires and everything is hooked up correctly.

I have read up on this and people have said the clean the flame indicator rod. I do not have one. I have replaced the ignitor (i broke the old one while cleaning). There is a black box with a small clear "window" next to the ignitor? Is this the flame indicator? How do I test this?

I have also heard the furnace click and nothing happened at all. When this first started happening, I wiggled wires and connections and sometimes the burner would start and stay on other times nothing happened. I have checked and cleaned all the terminals since then.

I have jumped the pressure switch and the same thing happens. I attempted to clean out the pressure switch hose outlet and the other end of hose on exhaust fan with a tooth pick. Nothing came out.

The furnace on the outside says RPJ comfortmaster II. On the inside it says Inter City Products Corp. Lavergne TN. Model and mfg #: GNJ100N12A1, Serial #: L9611 15861. I moved in the house four years ago but the furnace was installed in the mid 90's.

What is my next step? How do I test this thing out? I have a multimeter and tools but no money to pay for a repair man. Any help would be appreciated.
 
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  #2  
Old 10-29-07, 03:40 PM
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Comfortmaker is the brand. Take a look at the gas valve and see if it says SV9500M or similar. The wires you wiggled- they are on the gas valve? Does the top of the gas valve have 2 connectors? One set of wires goes to the ignitor and the other set goes to a solid state board? It sounds like you have a Honweywell Smart Valve and it also sounds like the valve is bad. But first post back with the type of ignition system you have; it will either be the Honeywell SV system or a White Rodgers module # 50A50xxx. Once we know what you have, we can walk thru a troubleshooting procedure.
 
  #3  
Old 10-30-07, 08:30 AM
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Hi, thanks for the reply. The module is a White Rodgers model 50A52-111, it also has HQ1009947wr on it. The gas valve has only 1 connection of 4 wires that plugs in on top. The flame sensor (i think its a cad cell or infared sensor) is a White Rodgers 960-21, it also has h01009948wr and L9609e2 on it.

When I wiggled the wires before, Im not sure which ones I did. I think I did them all.

I would appreciate any help you can give me
 
  #4  
Old 10-30-07, 01:48 PM
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HI Pooch:

Tell me about the 4 wires and where they attach to the gas valve- do they attach to a small circuit board that plugs into/onto 4 pins sticking up from the gas valve? The circuit board is held in place by 2 screws? Can you get a part # off of the gas valve?
 
  #5  
Old 10-31-07, 07:57 AM
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Thanks again, The 4 wires clip in on top on some type of black board. I didnt look at the number of screws. I took a picture of it and other parts of the furnace but I dont know how to post it on this.

The wires are blue that goes to the pressure switch, white orange and yellow that go into a plug in to the bottom half of the furnace and then it goes in to the module. White to the GC, Orange to GR and yellow to GM.

I didnt see a # on the valve itself but on one of the plastic pieces on top there is a 36E35 202 and under that is HQ1009954WR.

The furnace is working fine the last 2 days. But I would like to know how I can diagnose the problem when it happens again. I know it will happen again and I want to fix the problem and move on to one of my other projects. Any info you can give me will be appreciated!
 
  #6  
Old 10-31-07, 08:18 AM
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Hi Pooch:

OK, don't taze me pooch, but you might want to get out the prayer cloth. I'm pretty sure what you have is the WR radiant sensor ignition system. It was used by Trane, Amana and ICP. It's obsolete and replacement parts are unavailable. The fix is a complete new ignition system that comes as a kit. $$$ You would need to contact a service company to address it. Considering the age of your furnace, if it dies, you might want to replace it the furnace.
 

Last edited by daddyjohn; 10-31-07 at 08:19 AM. Reason: spelling
  #7  
Old 10-31-07, 01:45 PM
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Thanks John. Is there a way to test my gas valve and make sure that is not the problem? I would hate to buy the kit, change everything over and find out that it wasnt the problem.

I ran into a friend last night and I thought she worked at a plumbing place but it turns out it is plumbing and heating. I talked to a guy there and he told me he can get me the kit for $205.00 plus shipping in. I would like to make sure that it is the module or the flame sensor before spending the cash.

The module that I have, are they known for this problem or other problems?

Thanks again!
 
  #8  
Old 10-31-07, 02:01 PM
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I looked up the gas valve # and it comes back the same as the module; obsolete, no replacement parts available. That module was only ever used on that type ignition system. The achilles heal in the whole thing is the radiant sensor. The kit replaces everything- gas valve, module and ignitor and flame sensing device. I would suggest that before you take the plunge, you have a professional tech come over and check the furnace to make sure it's not something else. From your description however, it sounds like the sensor is intermittent. I can only do so much over the net. BTW- that sounds like a good price, just make sure it's the right setup for your furnace.
 
  #9  
Old 11-14-07, 11:08 AM
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Thanks again for your help. The kit came with a new board, new flame sensor, wiring harness and burner covers. The instructions were very good. It was pretty easy to do, I finished in about an hour.

The instructions says to leave the radiant temp sensor wired in but it did have instructions on how to by pass it. Is there any reason to leave the radiant temp sensor in?
 
  #10  
Old 11-14-07, 02:21 PM
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Hi pooch:

I'm happy you have your heat back. I'm not sure about the radiant sensor, I can't think of a reason why it would still be needed. However, I do know the sensor was the problem with the old configuration. I've learned the hard way, when all else fails, follow the directions. he he
 
  #11  
Old 11-18-08, 06:36 PM
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Had same unit, same problem

I know this is an old post but what I say here may help someone out. Have same unit, Comfortmaker RJP II or whatever crappy name they gave it, with same symptoms same control module, etc. The solution may be in the clicking sound when jiggling the wires at the gas valve that the the original poster talked about. Tapping and moving the connector or wires makes a clicking which I believe must be the gas valve solenoid intermittently closing and opening due to some weak terminals in that little 4 wire connector This eventually shuts off the gas. Then flameout and cold air ! I used contact cleaner on that little connector to no avail.
I put a tie wrap around the wires on the connector, tightend it, thus forcing the terminals together more tightly to make better contact. No clicking when I jiggle it now and the furnace is working fine so far. I have a hunch were talking simply an intermittent connector! Shame to spend 3-400 dollars on retro kit when the problem may be this simple. I'll post back in a few days if I'm wrong and she quits working again. Ive been fiddling with this for 2 days. It may have been this simple-I hope.
Best Regards,
Rich in NC
 
  #12  
Old 11-19-08, 12:56 PM
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Originally Posted by rlanghoff View Post
I know this is an old post but what I say here may help someone out. Have same unit, Comfortmaker RJP II or whatever crappy name they gave it, with same symptoms same control module, etc. The solution may be in the clicking sound when jiggling the wires at the gas valve that the the original poster talked about. Tapping and moving the connector or wires makes a clicking which I believe must be the gas valve solenoid intermittently closing and opening due to some weak terminals in that little 4 wire connector This eventually shuts off the gas. Then flameout and cold air ! I used contact cleaner on that little connector to no avail.
Thank you for the comment. I will take a look at my wires and maybe this will solve my problem...

Were those tiny little tie wraps you used? Those connectors are so small.
blue3
 
  #13  
Old 01-04-09, 11:50 AM
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Same problem here.

After years of intermittent operation, and trying most if not all the troubleshooting procedures above, a loose 4 conductor connection on the 36e35 205 gas valve proved to be the culprit.

A tie wrap works, but not a well as a shim wedged in on the side of the connecter.
 
  #14  
Old 12-07-09, 10:29 PM
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I have had the same intermittent operation problem for 2-3 years, but recently solved it.

Symptoms: After the furnace would initially turn on and operate properly for 2-20 minutes, the solenoid (the small one) on the right side of the gas valve would start 'clicking' every few seconds. It would then start clicking faster until it sounded like maracas. At that point the flame would start to get smaller then go out. The HSI (hot surface ignitor) would come on and sometimes the gas would restart and sometimes not. If not, someone would have to move the switch on the thermostat to OFF then back to HEAT. The process would start over again and maybe work for a while. My unit also seemed to be vibration sensitive due to the forced air fan and squirrel cage movement. When the clicking would first start, I could grab and hold the gas valve and the clicking would stop for a while.

Judging from the model and serial numbers, my furnace is about 6 months older than POOCHIESTYLE's. Model GNJ100N20A1 ser#L9537 47298. But with the same control board and gas valve units. I solved the problem by taking off the flame sensor (small black rectangular box with a clear window on top looking up at the flame) and giving it a good cleaning (the window was covered with a *thick* layer of dust and dirt.) (Yes, you have to take a bunch of other stuff off to get to the little sucker!) I also took off the plastic housing between the solenoids on the gas valve and discovered several 'unhealthy' looking solder joints. Resoldered those connections (one on the large power resistor, one on the rectifier and one of the connector lugs to a solenoid. Reattached the plastic part and connected the 5 position (but only 4 wires) connector and it's been working like a champ since.

Can't say which 'fix' worked but it's 2 more things you can try that you didn't know about before. Also beats the heck out of a $200 gas valve or a $350 control board replacement. Hope this helps someone else with this sorry POS furnace!
 
  #15  
Old 01-15-10, 04:25 PM
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great write up engineer. i also had this problem exactly as you described, furnace would turn on then turn off 2-15 min later, as well as hearing clicking noises from the gas valve solenoids. i have a upstairs and downstairs furnace and they are identical so that helps with the troubleshooting. tried switching to the known good resistor pack (black plastic thing on the gas valve) that controls the solenoids and that didn't work.

Eventually took off the manifold to get to the radiant sensor (obsolete flame sensor) next to the ingitor. after cleaning the window which wasn't that dirty, i wanted to see how it worked so i took it apart (not that hard just bend the metal off) and figured it was just a switch that bends between two contacts when next to a flame (heat?) then tested the resistance between the brown and blue wire (these should be closed when flame is on). The resistance was shaky and not closed so i took some sandpaper and cleaned the contact. put everything back in and no more cold nights for me!

thanks engineer, you headed me in the right direction with your post and i hope my input can help the next reader.
 
  #16  
Old 10-22-10, 08:10 PM
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Lying Contractors

I understand your pain. My fiance and I bought a house, and after moving in, the furnace stopped working. No need to go into details, but the POS furnace Comfortmaker, was experiencing all the same symptoms described by all the posts. Make a long story short, I was not able to troubleshoot as I was traveling. Had my fiance call Shamrock Heating & Air Conditioning (Carol Stream) to have them check the furnace out. After inspection, the Expert Technician & Lead Installer informed my fiance that the main module (505A55-843) had burn marks. Secondly, the gas valve was bad because it was jittery. He said the cost of repair would be $1,100. However, he recommended we replace the furnace with a high efficiency furnace for $6,000. They were so eager to sell us a new furnace. After I inspected the circuit board, the burn marks he referred to were little yellow spots and had my fiance touch them and told her that they were a little warmer then the rest of the circuit board.

After I read the comments, I wedged the valve, and everything has been working fine ever since. And one more thing, the company that did the inspection, also installed this POS in 1996. I also found per the forum, that the radiant sensor had been removed from the circuit and the two (2) blue wires were jumpered. They probably could not get this to work when they sold the furnace to the original owners, and hence improvised.

Long story short, thank you to everyone that contributed to this forum and shame on Shamrock.
 
  #17  
Old 10-23-10, 06:33 AM
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Wazzy, it's annecdotes like that that makes me trying everything before giving up and call a service man. It's shameful and unnecessary.
But back to your finding of the jumped sensor, isn't it the sensor needed for proper operaration ?
 
  #18  
Old 10-25-10, 02:32 AM
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Question Rheem Classic 90 Plus

I had a Rheem Model RGRA-10EZAJS propane furnace installed in 1997. It will light (seemingly without fail) if I remove the covers (exposing the burners and blowers), and hold in the cover switch button. But then wonít light after that, when called for by the thermostat alone. Igniters arenít triggered at all. The small vent blower runs for awhile activating the vacumn switch (which Iíve replaced, and checked for continuity) that signals the rest of the unit to proceed with ignition. Iíve checked all vents, which of course could prevent ignition. I found a drain hose that was cracked, I replace it (second time, differend hose) with no change to problem.
It seems like it will only ignite if it is re-booted, so to speak.
 
  #19  
Old 10-25-10, 06:50 AM
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While it might seem like a good idea to piggyback on previous threads, it tends to be confusing for those who might offer advice.


My suggestion is to repost on a new thread.
 
  #20  
Old 04-29-12, 07:01 PM
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igniter lites but then goes out

i have the same furnace as the rest of you according to the model#..the igniter would glow and then a click sound and then it goes out and no lighting the burner..i took the flame sensor box out took it apart,,i sanded with small piece of sandpaper between the contact points,,then blew the dust out ..cleaned the piece of glass real well and flipped it around and put the cleanest part through the window..when i put it back together i bent the igniter closer to the flame sensor window by 1/4"..has worked perfect for days,, many calls for heat and lites right up every time,,i appreciate this blog ,,it gave me the confidence to fix without the upgrade kit,,thanks alot guys
 
  #21  
Old 10-08-13, 12:33 PM
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OMG, have replaced many parts for the same problem and was ready to get a new gas valve. Then checked the wiring harness on top of the valve and it was clicking on and off. So I wedged it with a piece of plastic till it was snug and furnace runs great. Do this first before you start buying parts like I did.
 
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