Last Spring, after running fine over the winter, my home gas furnace started acting up and turning the inducer draft motor fan on and off by itself like it was turning on the heat. It did this even when I turned the thermostat off or turned on the blower (fan) or even the A/C. And the board flashed code 22. I finally undid the lead to the inducer draft fan and just let the board blink since I didn't need the heat on anymore. when I tried the heat later it would not even come on at all - no inducer motor , nothing. however the a/c and blower still worked over the summer and the board went back to a steady glow with no code flashing. now I need heat so I replaced the z007 board with a retro fit ICM 282 board and it did the same thing - it ran the blower and a/c but no heat. also when I run the self test on the original board it does the self test just fine - runs inducer motor, runs blower motor at both speeds and lights up the glow plug. but nothing from the furnace goes into action when I turn on the heat from the thermostat. I'm gonna switch out the wall thermostat since I already tried a new board.

any suggestions?

I put the old z007 board back in since the new ICM board didn't act any different or restore the heat.

Carrier Furnace Info.-
MOD 58PAVO70-12
PROD 58PAVO70-13112
SERIES 130
SERIAL 0395A12715
Furnace control board info -
United Tech Elect controls (Furnace Control Board/module)
1012-940 MODEL HK42FZ007
ANSI Z21.20-1993
CAN/CSA - C22.2
NO. 199-M89

 

I really don't like those 1/3 priced ICM boards. I have had to replace too many brand new ICM boards installed by homeowners to trust them.

Does your white flame sensor wire appear undamaged between the board and the flame sensor?

You can take a picture of your existing stat wire connections at the furnace and remove all stat wires from the furnace and then jump R to W to test heating operation.

If you replace your stat avoid the cheap replacement stats. You get what you pay for and a twenty dollar stat is not as dependable as a sixty dollar stat.

 

Thank you!. I will try that jump. Is that different from the test jump? The ceramic appears fine and I cleaned the sensor with a piece of paper that I read somewhere else on the web. what bothers me is that nothing comes on at all like there's no juice. I have not switched the thermo. was too tired last night. will get back to you.

 

I didn't like the ICM Board. had to use the wire harness with allot of extra wiring and couldn't put the cover back on over the board. it would not fit like it fit my original z007 board. where can I get a new z007 board if not an ICM retrofit? Ebay ?

 

Your thermostat connects the W (heat) wire to the R (24VAC power) wire for heating.
This test gives your furnace the heating demand that it requires to go into the heating mode.

You can measure for 24 volts AC between W and C (24VAC common) to see if the furnace is getting a heating demand.

An OEM board would also be a kit. While I believe that you need a board, this should be tested further before spending any money on parts.

 

I did the R to W test but no gas flame - should the gas come on? the inducer worked, the glow plug etc but no gas was released or ignited. is that right or is that the problem? then it flashed 12 for r-w jump. what next please?

 

It should give you a code 12 for ~90 seconds while running the blower.
Then you should see the induced draft motor run, the the HSI should glow and then the gas valve should open.
After ignition and a warm up period the blower should start.

While I could probably post the listed sequence of events, I would like to know what LED code you got after ignition failure.

 

21 - it that why no gas comes on? do I have the gas turned on right? the blue knob on the 'gas box' faces me saying on , right? and the plumbing gas valve knob runs parallel with the piping?

 

per the code 21 listing it says - stuck gas valve relay on cotrol or miswire to gas valve circuit.......

 

Are you getting 24 volts AC to the gas valve after your HSI glows?
Some gas valves also have a toggle switch on them. Do you have this switch?
Is it on?

 

where's the gas valve? on the gas box with the blue knob for gas on/off or is it the silver diaphram located higher up to the right? (that might be the pressure switch). please advise.

 

The gas valve has the blue knob. It looks like valves either have a knob or switch, not both.

Here are some gas valve examples...

 

no, it is at 15 before the test and stays that way..........15 volts. all the time.

 

15 volts AC all the time?
This sounds like a faulty control board.
To check your meter, (and the transformer) you can measure for 24 volts AC between R and C at the control board.

 

how much current should be there before the test please? 0? 15 is there all the time except when I turn off the power switch on the wall to the entire furnace. which kills the control board.

 

You should have no power to the gas valve until the ignitor glows, at which time you should get 24 volts AC.

Do you have 24 volts between R and C ?

 

I get 27, btw R and C - close enough? or does it have to be exactly 24?

 

27 volts is a good reading between R and C.

 

I just hit r to comm (instead of r to w) and blew the fuse. have to get another one. sorry. hope I didn't ruin the board (maybe it's shot anyway because of the 15 volts?). I'll be back after getting a fuse at the store. it's the big type (my car uses little ones mostly). pls don't go away. you are wonderful.

 

You already have a spare fuse on the other board.
I would reinstall the ICM if it was already in the house.
I have seen flame rectifications issues with the ICM board.

 

what other board? I mailed back the ICM board and am awaiting a refund from the vendor.

 

Probably a wise decision.
The OEM board costs more but dependable operation has a value.

 

and it still didn't turn on the furnace.............be back.

 

question while I"m gone - you mentioned that board might be bad but if board is bad then why does it run the self test fine? (test spade to comm). just curious. be back soon I hope.

 

Did your gas valve turn on with the self test?

 

no, my understand is that the self test to the test spade only runs the glowplug and motors. right? and there is no fault code with the self test but your test of r-w does keep givning me a 21 definitely. and still only 14-15 volts on the wires to the gas control valve whether I run any test or not. where to go from here? replace the board again? you said I should have no voltage to the gas valve at the beginning of the r-w test and I do and it never goes up to 24 volts.

 

I agree, the self test does not check the valve and you have an issue with voltage to your valve so your self test would not apply. This answers your question on post 24.

I'd disconnect the 2 wires to the gas valve and measure the voltage to them and measure the resistance (in Ohms) across the gas valve leads, but I still think that you need a new control board.

 

I have already been disconnectiong the leads to the gas valve to connect to the probes of my multimeter. I only get 14-15 volts. did I do that wrong?

 

I usually test for 24 volts to the valve while it is wired in and disconnect and test if the voltage is low as you have read. You have eliminated a step but this proves that it isn't a good board connected to a bad valve.

I would still measure for resistance across the gas valve but we do need a new control board.

 

resistance is 0.8 ( I check that with the furnace current off, right? ) if I turn on the furnace current, resistance goes off the scale.

 

You should unplug the wires to the valve before taking an Ohm reading across the valve terminals.
You should never take an Ohm reading with voltage present since this can damage your meter.

I'd expect ~ 13 Ohms.

 

i did unplug them. one of them is sheathed so I have to stick the meter probe in the very end. that's why I cant measure voltage to them plugged into the terminals. the spade terminals on the valve measure zero resistance. the wires that connect to the two spade terminals for the gas valve still measure 0.9 but I have a low battery (uses a 9 volt) which might be why it' s not higher.

 

The isolated gas valve should measure around 13 Ohms.
Are you measuring zero Ohms or volts across the gas valve terminals?

I wonder if your gas valve took out the board.

 

no the board led is glowing. do you mean the wire leads that plug into the spade terminals on the actual black valve component? the resistance between the wire leads is 0.9. (i don't know what scale for ohms that is). the spade terminals themselves on the black valve component read 0 .

 

Zero Ohms across the valve terminals? Sounds like a dead short.
Does the valve smell burned?

I'm beginning to wonder if a gas valve failure damaged the control board and caused the issue that we are having with a constant 15 volts.

Are you confident in your resistance measurement?

 

when you say terminals, do you mean the leads on the ends of the wires or the spades you plug into with the wires? the spades are the flat prongs on the black valve component you slide the wire leads onto. the wires measure 0.9 and the flat prongs (like blades) on the valve control read nothing. no I am not cofident because I have a low battery reading. I will get a new battery at the store tonight.

 

I'm talking about the valve. Not the wire to the valve.
Getting a new battery is probably a good idea before we condemn the gas valve along with the board.

 

The ohm dial is pointing to either 2M or 20M ohms and I still get 0.9 from the wire leads and 0 on the mounted spades on the control box itself. I also tried a diff battery and still only get 14 volts off of the valve wires and they are sending 14 volts all the time.

 

the control valve is the black unit screwed into the gas box right? that's where I've been working with the wires..............

 

Actually, if you are in millions that is probably a good reading. Is Ohm 20K an option on your meter?