33 replies to this topic

[torchkeeper]

Furnace goes through cycle all the way to firing . Only fires for 1-2 seconds then shuts gas valve and goes through sequence repeatedly till shut out. Red signal lamp flashes 4 times. Now I have added a ground from case to ground rod outside. tried cleaning flame sensor ,then replaced flame sensor. Nothing changes. I have taken each and every connection to control board off and on. Only thing I cannot seem to figure out is I get no flashing or any lighting from yellow flame indicator light? Never lights at all , it used to. So what do I check next ? I have service manual and installation manual for this furnace. Only change is I moved furnace to new build home on my same lot . It is a propane fueled furnace ,same gas tanks,regulator and gas supplier as old house . So I don`t think gas pressure is problem. Why no yellow flame indicator light? Bad control board?
Thanks as usual to ya`ll.

[jumptrout]

There is a code list on the front panel.
What are the 4 blinks described as?

[torchkeeper]

" ignition failure", unit will try 5 times for ignition. auto reset in one hour. that`s what is stated in service manual. and panel

[jumptrout]

You are lighting.
You have a good flame sensor.
The yellow flame light on the board does not recognize a flame.
Bad board.

[Daveb1972]

Jumptrout is right, probably, just one other item to check....the flame rectification schemes are all polarity sensative, the L1 terminal on the main power MUST be 120vac hot, and the L2 MUST be neutral, and the chassis MUST be grounded. If after those checks you still have the same problem, then I'd replace the control. If you have trouble finding the correct OEM board, then check out the honeywell s92000 universal board, I use this frequently with good results.

[torchkeeper]

Checked polarity, l1 is on hot lead does not say l2 or I`m not seeing it on board. Just shows a grouping of white wires all listed as neutrals. But the neutral power lead is on this group of neutrals. The green from circuit panel is on chassis. I also added a chassis ground to a ground rod 6 ft. into ground as a back-up for ground.Guess I`m ordering a board today . I`ll post the results.Thanks guys for the help.

[jumptrout]

When you pull this board you will probably notice corroded solder joints on the back.

[torchkeeper]

Checked that before , clean as if it was new ?? My mother`s lennox furnace board burned through in a spot years ago. So I`ve learned to look for that. The furance was in a crawlspace in old house.Damp, but furnace has no rust in case or on exchangers. We have wood fireplace and a pellet stove ,so furnace has very little use over past 10 years. Maybe 100 hours total. Probably trouble because of such little use. I ordered the honeywell s9200 ,Thanks Jumptrout .

[Bullstok]

did u actually measure the dc microamps? hope so.

[torchkeeper]

I tried ,put meter in series between sensor rod and wire to sensor rod. But the flame only fires for mayne 1-2 seconds and valve closes. If I am getting a reading it may not have current long enough to register on my meter. Not the most expensive one. What puzzles me is nordyne service manual says furnace should fire for 6 seconds while sensor proves flame, this one only fires for a second ,maybe 2 seconds?

Edited by torchkeeper, 21 November 2012 - 09:21 AM.

[torchkeeper]

could gas valve be bad ? If soIenoids in valve are weak they would not hold valve open long enough to prove flame. Only hear one click from valve? Looks likr 2 sets of windings inside valve. How do I know if valves are opening and have enough current to stay open? I have 24 volts when valve opens then .click valve shuts no more voltage. Why does valve not stay open for more than 1-2- seconds? manual says 6 seconds to prove flame? Control board or gas valve?

[Bullstok]

check ohms on gas valve solenoid with wires disconnected (sometimes this is helpful, sometimes not, depending on the valve & type of coil wiring. ie: diode involved or not, etc). you can also check gas valve amp draw & compare to valve rating if provided.

also check for how long the gas valve actually receives 24v. you may have done this. i wasnt sure from ur post.

chances are still pretty high that the board is the problem.

Edited by Bullstok, 21 November 2012 - 08:24 PM.

[torchkeeper]

New board installed , nothing changed. Goes through sequence  4 times and goes to soft lockout. Green e-com lights as per manual. The flame sensor light never comes on. I have cleaned burners and as stated replaced flame sensor. I used  Honeywell s9200u1000 as the replacement. Goes through sequence fine just will not stay lit. Propane tank is full. What next?? Gets 24 v. for the 3-4 seconds it fires and valve shuts no voltage then.

[jumptrout]

FOR TESTING ONLY! Bypass the rollout switches and see if it stays lit.

[Bullstok]

this a wild shot, BUT... now that you mentioned "LP" again (i missed it in original post somehow), does the gas valve have a low pressure cutout switch? they are sometimes added to the gas valve during conversion to LP. if the pressure drops they cut the voltage to the gas valve. they are generally used to keep the furnace from burning poorly when the owner forgets to fill the tank and pressure drops off. if you have any gas supply pressure issues (tank regulator or house regulator or pipe obstruction, etc) or if the pressure switch is going bad, then this could happen:

 

the gas valve is closed, the gas pressure is built up in the lines behind the closed gas valve to the normal operating pressure, the pressure switch is closed because of adequate pressure - allowing voltage through to gas valve, board sends voltage, the gas valve opens, the gas starts to flow, the gas flow is low therefore the pressure drops, the pressure switch senses the low pressure and opens, the voltage to the gas valve gets cut out. repeat.

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Edited by Bullstok, 28 November 2012 - 09:37 PM.

[Shootist]

Odd symptoms. If I'm not mistaken the Nordyne furnaces will error out immediately if the power polarity is reversed on initial startup. I would still expect you to get some sort of yellow light when the burners light; it seems like the yellow light should blink if there was a weak flame sense. Check the blink code list and see if there's anything listing any blink codes for the yellow light. Did Nordyne use a Honeywell board in the G6 furnaces? I've always used the Nordyne OEM boards in the past. As a last resort try using an outdoor extension cord and plug into a different receptacle that has a good ground. We don't use propane much down here so there may be something to that "low-pressure" suggestion.  

[torchkeeper]

i`m getting ready to use manometer to check pressure being delivered to gas valve. I`ll post in a little while with number  . Thanks to all for staying with me on this ,I do appreciate it. also the error code for flame sensor lightis as follows right from nordyne book.

flame  yellow light

low flame sensor signal = continuous flash

flame present = light on

yellow light will come on solid @ 1uA  or more

yellow light will blink@ point of weak signal and go out @ .5uA or less

 

 

 

I get no lighting of yellow at all on either nordyne board or honeywell board .

 

 

Does it matter which spade terminal on gas valve the brown wire and yellow wire go to? Polarity I assume. schematic from nordyne only shows the two wires leading to valve , does not state which wire goes to which terminal.

Edited by torchkeeper, 29 November 2012 - 01:02 PM.

[Shootist]

24v polarity on the valve shouldn't matter. If the roll-out switches are tripped the furnace would lock out and you get an "open limit" error. Same goes for the main limit. Furnace will not attempt to light with any open limits.

If you have a meter check the flame sensor wire between the sensor and the board for continuiety. You can unplug the molex connector from the board and test it with your probe if need be. I'd try a new flame sensor first thing but then I keep them on my truck. Less than $20 so you may want to track one down. If the flame sensor was dirty you'd have a blinking yellow light. It almost has to be a bad flame sensor or bad wire.

Edited by jumptrout, 29 November 2012 - 08:14 PM.

[jumptrout]

He said he already replaced the FS.

[Bullstok]

if the gas valve dont stay on more than 2 seconds: it aint the flame sensor. there is not enough to sense. therefore the problem is related to why the gas dont stay on long enough. you have to keep order of operation in mind.

 

generally:

 

call for heat. (t-stat sends 24v back to heat)

safety circuit check. (high temp limit(s) & rollout(s) checked)

inducer on. (pre-burn purge)

draft is proved. (inducer pressure switch, centrifugal switch, etc)

igniter comes on.

gas valve opens.

flame ignites.

flame is proved.

warm up.

blower on.

 

we barely get into flame ignites but we know that the actual ignition is not the problem because it ignites AS SOON AS the valve opens. if there was a noticeable delay in ignition from the time it opened then "flame ignites" would be the problem. so "gas valve opens" is the issue. either it is taking too long to open from when it is supposed to or it is not staying open long enough, check all things needed for gas valve to open on time and remain open with good flow.

 

how long (and at what point) does valve get 24v. do not go by the click of it opening. go by the volt meter. if it has 24v but takes precious time to open that is bad. the time you get to prove flame starts when voltage is sent to the valve (or supposed to be sent). not when the valve clicks open (the board does not know the point that the valve actually opened). unhook the 2 wires from gas valve. hook to volt meter. time how long igniter is glowing before 24v is on wires. how long does it remain on wires? same with valve hooked up or not? coil resistance? gas valve amp draw?

 

this is why i asked about a low pressure switch. it is between the board and the gas valve electrically speaking (if you have a low pressure switch)

Edited by Bullstok, 01 December 2012 - 03:10 PM.