Tempstar furnace diagnosis?


Old 03-02-08, 06:10 PM
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Join Date: Dec 2007
Location: U.S.A.
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Originally Posted by DixieH View Post
Also, I read another thread somewhere today where someone suggested that one could also hold a lit candle up close to the burners (while they are either coming on or currently operating) and that if the candle flame moves at all then it would be an indication of rollout....would this really work?
It'll be hard for you to try the candle test b/c of the wind. Remember, your unit is in your backyard, exposed to the outdoors and winds. This test will work with a unit in a closet or in a basement.

The candle test would have to be performed with the fan ON but the thermostat not calling for heat. bring the candle as close as you can to the burners (which are OFF)...if you have a crack, air will be moving from the house-air side into the combustion-air side of the heat exchanger, and will make the little flame of the candle waver.
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Old 03-09-08, 02:13 PM
Thread Starter
Join Date: Jan 2006
Location: south Alabama
Posts: 73

I meant to post this several days ago, however I got captured by swollen tonsils..followed by a 102 degree fever...followed by 2 days of the common cold..

Anyways, I decided to go ahead & call a HVAC tech out (since a frequently tripping flame rollout switch could be potentially lethal at some point) to give his pronouncement on the situation..

The HVAC tech says: "damaged heat exchanger/combustion chamber"....then he reached up and flipped the switch on the Smart Valve to the "OFF" position before closing the panel back up.

Verdict: either fix the heat exchanger or get a new unit.

However, I watched him the whole time he had the panel open and he never used any tools or anything like that at all....he simply put the back of his hand close up to the burners (while they were going through the ignition process) and then I heard him say that "he could feel it" (presumably the rollout). He also told me that (due to the heat exchanger) that it was blowing pure carbon monoxide into the house...

This is contrary to what pflor told me in an earlier post prior to me calling for the HVAC tech to come out..

Regardless, I'm going to begin the search for a new unit anyway...

Fortunately, the azaleas have begun to bloom this week and the need for heated air has diminished....the A/C on the unit still works also and I'll have a little extra time to look for the best unit I can get to replace the old dinosaur..

Since the price of natural gas has started to ascend upwards so much..then I figured that I would replace my unit with a heat pump instead..

Anybody out there got any ideas about the best kind of heat pump for my situation would be?
Old 03-09-08, 04:25 PM
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Join Date: Dec 2007
Location: U.S.A.
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The guy that checked your furnace does not know what he's talking about. For one simple reason: if that furnace was, as that "bad tech" put it (he surely should be called something worse than "bad tech", but on a public forum let's leave it at that)...as I was going to say...if your furnace was blasting pure carbon monoxide, you'd be dead by now and this message of yours would have been written from the netherworld. You can't have CO with the ample supply of fresh air surrounding that "outdoor mounted" unit of yours.

Now there is a lot of rust evident around the heat exchangers, as your pictures show, which tells of an aging unit. But rust is not the same as soot. Excessive soot build-up tells of incomplete combustion and CO...excessive rust is not the same, it tells that the HX is old and likely cracked too.

Yes, you probably have a bad heat exchanger, and yes, time has probably come for that unit to go into the retirement home...but this person is trying to push for a sale and imbed in you panic and a sense of extreme urgency so you buy from them right away.
To find out if you have CO there, he needs to use a CO-tester, a digital instrument capable of measuring the PPMs of CO present.
To determine if the HX has a crack, he needs to inspect the HX, at the very least with an inspection mirror.

Yeah winter will soon be over, don't rush, find out from the Better Business Bureau in your area about reputable contractors and take all the time in the world getting the most reputable amongst them. And if you decide on a heat pump, may I recommend a Geothermal system?
They will cost you plenty to install, but is green technology and beats any other system in performance.

Last edited by pflor; 03-10-08 at 03:03 AM.
Old 12-06-08, 12:39 PM
Join Date: Dec 2008
Location: pa
Posts: 9
hi guys new here so im not quite sure how to ask questions. this is for PLFOR, after reading your post to DIXIEH, which are quite informative i decided mabye this help forums arent so bad.(they have always seemed to involved to try.)anyways my problem is similar to dixies.
1. after initial discovery of cold air blowing when it is supposed to be hot. i followed the shut down/restart procedure.
a-turn thermostat to off
b-turn off elec supply
c-turn off gas control switch
d-wait 5 minutes
e-dont smell gas
f-turn on gas control switch
g-turn on elec supply
h-set thermostat to 72
At this point furnace comes on, small flame ignites into big flame, furnace heats house to 72 degrees. Now comes the problem, once the house cools down and it is time for the furnace to kick on and heat the house back up it does the following.
a-the little flame comes on and ignites into big flame and goes right back out. now there is know flame visible. yet the fan will continue blowing indefenitly.
If i go back through the restart procedure(a thru h) it will kick on and work through the heating cycle 1 time. after that it is a never ending cycle, after 1 heating cycle i have to restart it, 1 heat cycle restart over and over.
Old 12-07-08, 01:42 PM
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Location: U.S.A.
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More info is needed to get a good mental image of what system you have there.

You seem to have either a standing pilot OR an intermittent pilot ignition system. Hard to tell since you have not provided MFR and M/N data, which is necessary. And hopefully your unit won't be a York, b/c the guys at York are not helpful at all in providing tech docs about their units (the older ones), they only post on the web data for their most current systems.

One last thing, you should consider starting your own thread, for the benefit of others that may come across and even be willing to pitch in.
Old 12-07-08, 02:36 PM
Join Date: Jan 2008
Location: Tennessee
Posts: 479
Heating Help

You are experiencing a flame recognition problem, first check all, and I mean all wiring connections in your furnace. This problem is often caused by a bad ground, if you check all the connections and the problem persists you may want to replace your pilot assembly if it is spark ignition or flame rod and cable.
Old 12-07-08, 07:48 PM
Join Date: Dec 2008
Location: pa
Posts: 9
Thanks plfor and mike, my new thread is cold air? i started it yesterday. as for the gas valve and the ignitor it is the same as the ones dixie had. the gas valve is a honeywell sv9501 2729 and looks just like the one in dixies picture, the ignitor is also the same. this is a comfort maker unit. i would appreciate any help u can offer. i wont be using this thread anymore, i am sorry if it has caused any problems.
Old 12-07-08, 09:05 PM
Join Date: Jan 2008
Location: Tennessee
Posts: 479
Smart Valve

I did not know it was a smart valve. Many problems with this valve. If you try the other things and the problem persists you will probably have to replace the valve and they are a little expensive. Most times the problem is where the igniter plugs into the valve and you can buy some time by firmly pushing the plug into the receptacle but once they have problems it is just a matter of time.
Old 12-04-09, 09:32 PM
Join Date: Dec 2009
Location: Oklahoma
Posts: 1
I have a comfortmaker (i'd state what i have has the model # but it doesn't seem to match any actual company model #s..) - and the igniter looks just like this

the igniter i picked up at a store is the M shapped one that shows up everywhere on google (robertshaw?)

Are they interchangeable? The new one came w/ quick disconnect plug in's on it, but it looks like i'm going to have to do some splicing if they do indeed work.

just askin b4 I dig in.. guess i'll have to put the project off some more.. *sigh*
Old 12-05-09, 05:14 PM
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Location: Wisconsin
Posts: 8,629
The width and length and mount may all be critical in your decision. It has to be in the furnace so it optimumly can fire off the gas as soon as the gas valve opens without a delayed ignition (that delay and WOOF!).

Although - even furnace men will substitute factory parts for even those aftermarket spirally ones, that are supposed to last longer. And/or try the most el cheapo one that works. They can be had for as low as about $20. Whatever you do, make sure like I said, that it fires off correctly.

I remember when I had to install an HSI on a water heater, there were insturctions that said the tip had to be so many fractions of an inch away and down from the burner. Electrodes on oil burners have such specs also.
Old 12-20-09, 05:53 PM
Join Date: Dec 2009
Location: TN
Posts: 1
Originally Posted by pflor View Post
A dangerous level of Carbon Monoxide (CO) develops when the burners do not have sufficient air for combustion. Your unit is an outdoor packaged system, it has plenty of air for combustion. CO should not be a concern.

Just picture what happens every time we turn on the stove in our kitchens to cook. The ranges have an open flame right in front of our eyes. We have not gotten sick b/c of them, have we?
Sorry to ressurect this thread but I came across it by accident and I have information that I think might be important to someone.

Pflor, you seem like a guy who knows his stuff and I don't mean to argue with you and I say the following respectfully but here is my experience:

We had a cracked heat exchanger with this exact same model of unit. It was causing the rollout switch to trip. I reset it myself a couple of times before calling a tech out. Sometime after the second time I reset it, the carbon monoxide detector in our house went off.

Was it enough to be dangerous? I have no idea. All I know is we switched it off and got it fixed tout suite after that. CO is not something to be messed with.

Oh, just as an additional, does anybody know the part number for the plate the blower is attached to on this unit? Mine has corroded through (presumably from condensation). Also, the motor housing is a little loose and is rattling noisily while the motor is on. Can it be tightened up or does it just require replacing?
Old 11-08-13, 12:17 PM
Join Date: Nov 2013
Location: Canada
Posts: 1
You guys are awesome

I just registered with this site after having furnace issues myself. I found this board and have read the whole interaction between you all.
I am totally impressed with this whole process and interaction.
So much time being given to help out, very impressive.

I bought a "new" construction home that is actually one year old. The furnace has given us nothing but problems in that it just does not want to work as it should. High efficiency furnace, very temperamental.
I would have been very happy to stick with a mid-efficiency but did not have that option.
I had Atco gas come in 4 times, each time wanting to clean the sensor. Then finally got the company that the furnace was bought and installed the unit to come and troubleshoot the problem(not coming on even though it was getting a signal to do so). They actually replaced the sensor, did not solve the problem. The installation company has most recently replaced the thermostat because whenever I would try to raise or lower the set point, I would not hear a click.
Anyways, that was yesterday. Last night the furnace did the 6 + 1 light code(I believe it is 3 or 4 attempts, and then locks out a re-start for 3 hours before trying again). According to my wife(I am a shift worker)after the 3 hours, the furnace attempted to start, and was successful.
I am up in Alberta, Canada and this is not the time of year to be having this issue.
The installer actually came with a new control board yesterday but did not install it. The furnace works, but it does not work all of the times that it should. All I want is to have heat when it is called upon. I have never had issues like this with a furnace before.
Other homes in the area that were built by the same company, and that have the same furnaces, are not having this issue. Sucks to be me, I guess!

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