SOLVED! OFF TOPIC - Any HVAC Furnace experts here?? I need help!!

[dmc3csc]

this the board I orderrd

HK42FZ034 - ClimaTek Furnace Control Circuit Board Fits Carrier Bryant https://a.co/d/2bXXT0F

I am not saying it will not work, but my program does not show the HK42FZ034 as an acceptable replacement. However both the Hk42FZ034 and the HK42FZ014 show the ICM282A as a replacement.

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[Caliguy]

Being your knee deep in troubleshooting and now familiar with sequence here's some more insight however I would bet it's the PCB 99.9%.

The stat can infact send false signal to the PCB as the relays do act up on the SSM but its unlikely and I believe you swapped it out, I think you answered your question already. So try this...

At furnace disconnect G
At stat energize heat
At firnace visualize heat sequence and let fail on limit. If this works its the PCB and or flame sensor.

next..

At stat and remove it leaving sub base on wall
At furnace jump out R to W1 and G and watch heat sequence If it sequences correctly its the stat or short in wiring like a chafe. If it does the same PCB or sensor. This is if FAN starts 1st as mentioned.

NOTHING in this entire system will allow fan to run 1st in the sequence you mention other then the PCB or stat. Proof switches, sensors, nothing becuse of series as mentioned by previous HVAC member.

I just did a pressure switch test.. no continuity when it’s off. On first cycle (when it’s working correctly) switch closes, we get continuity, when fan turns on switch opens again. With wires plugged in it read at 27 volts.

So I’m going to disconnect G at the furnace now and run it to see what it does. When jumping to W and G and R on the second test, I assume you want me to use 2 jumpers? One from R to W and the second from R to G at the same time?

 

[Caliguy]

I am not saying it will not work, but my program does not show the HK42FZ034 as an acceptable replacement. However both the Hk42FZ034 and the HK42FZ014 show the ICM282A as a replacement.

the one you listed is cheaper on Amazon.

I went based off of this website.. it says that part number fits my model number

https://www.repairclinic.com/PartDetail/Control-Board/HK42FZ034/2347708

 

[Caliguy]

Being your knee deep in troubleshooting and now familiar with sequence here's some more insight however I would bet it's the PCB 99.9%.

The stat can infact send false signal to the PCB as the relays do act up on the SSM but its unlikely and I believe you swapped it out, I think you answered your question already. So try this...

At furnace disconnect G
At stat energize heat
At firnace visualize heat sequence and let fail on limit. If this works its the PCB and or flame sensor.

next..

At stat and remove it leaving sub base on wall
At furnace jump out R to W1 and G and watch heat sequence If it sequences correctly its the stat or short in wiring like a chafe. If it does the same PCB or sensor. This is if FAN starts 1st as mentioned.

NOTHING in this entire system will allow fan to run 1st in the sequence you mention other then the PCB or stat. Proof switches, sensors, nothing becuse of series as mentioned by previous HVAC member.

with G disconnected at the furnace in your first test, there is no difference I. Operation except the fan may have ran a error code 12 and an additional 90 second cycle

 

[XX4XEXX]

You can run 2 or tie them together. So if fan "G" ran like OP stated then it's the board. If your stating it didn't run and threw an error code 12 after ign and burn then it's the stat. If it didnt and threw a 12 code then its the board. We're searching for why fan runs 1st then ign then all off. Everything else e.g. safeties sound like you covered them however you can literally follow sequence and trip this thing up as you go. Board can sometimes be difficult to pindown and is why I suggested to jump G then remove G, with G removed it can not run unless board tells it to even without power.

Point being with G jumped to R relay can not rapid click unless board is bad, with G removed fan can not run without board being bad, with stat removed and this simulated at furnace it eliminates stat culprit. The previous parts installed were bot the original issue.

FYI these boards are about 350ish at cost. Tech installed probably 700ish. If furnace is old swap it they are plug and play.

with G disconnected at the furnace in your first test, there is no difference I. Operation except the fan may have ran a error code 12 90 second cycle

 

[Caliguy]

You can run 2 or tie them together. So if fan "G" ran like OP stated then it's the board. If your stating it didn't run and threw an error code 12 after ign and burn then it's the stat. If it didnt ing and threw a 12 code then its the board. We're searching for why fan runs 1st then ign then all off. Everything else e.g. safeties sound like you covered them however you can literally follow sequence and trip this thing up as you go. Board can sometimes be difficult to pindown and is why I suggested to jump G then remove G, with G removed it can not run unless board tells it to even without power.

Oh so because fan still runs with G disconnected, that means it’s the board? It’s sending power to fan when it’s not supposed to. Is that correct?

with G disconnected inducer fan starts, igniter glows, burners on, then fan on, inducer off, igniter and burners off. Then fan surging on and off continues (ie: no difference then when G is connected)

If I understand it correctly, if Board was good, fan wouldn’t have turned on correct?

 

[XX4XEXX]

Yes sir and cheers Mate! You nailed it. Fan is a slave to the board it can not run if G its command is removed at furnace. If you performed this at the stat you could still have a short in the control wires touching causing fan to run. For instance you could jump everything out at furnace and remove W1 and if it lit then board. Same with cooling or heat pump.

Oh so because fa still runs with G disconnected, that means it’s the board? It’s sending power to fan when it’s not supposed to. Is that correct?

with G disconnected inducer fan starts, ignore glows, burners on, then fan on, inducer off, igniter and burners off. Then fan surging on and off continues (ie: no difference then when G is connected)

If I understand it correctly, if Board was good, fan wouldn’t have turned on correct?

 

[Caliguy]

Yes sir and cheers Mate! You nailed it. Fan is a slave to the board it can not run if G its command is removed at furnace. If you performed this at the stat you could still have a short in the control wires touching causing fan to run. For instance you could jump everything out at furnace and remove W1 and if it lit then board. Same with cooling or heat pump.

This makes total sense, I will also check the wires for the fan to make sure it’s not getting hot wired from a different source as well when I replace the board. Im running around my house screaming you’re a genius!

 

[XX4XEXX]

FYI these boards are not cheap I'd guess 350ish a few years back, if someone will sell it without a license. If furnace is old dump it. Also alot of people use to shame Goodman however now they run 10 to 15 year warranty I think maybe 20 haven't checked in awhile and VFD IBMs if that's your thing.

One last test. Run G only and watch it.

Thanks for the compliment Mate like the other member I've got 28 years in now working on 750t and up centrifugal chillers. Sometimes you just gotta step back and look at it like a Jeep

 

[Caliguy]

FYI these boards are not cheap I'd guess 350ish a few years back, if someone will sell it without a license. If furnace is old dump it. Also alot of people use to shame Goodman however now they run 10 to 15 year warranty I think maybe 20 haven't checked in awhile and VFD IBMs if that's your thing.

One last test. Run G only and watch it.

Thanks for the compliment Mate like the other member I've got 28 years in now working on 750t and up centrifugal chillers. Sometimes you just gotta step back and look at it like a Jeep

Is it possible the fan would turn on with thermostat set to Heat and fan to Auto and G wire disconnected at furnace terminal of the board is good?

 

[mantronics]

Oh so because fan still runs with G disconnected, that means it’s the board? It’s sending power to fan when it’s not supposed to. Is that correct?

with G disconnected inducer fan starts, igniter glows, burners on, then fan on, inducer off, igniter and burners off. Then fan surging on and off continues (ie: no difference then when G is connected)

If I understand it correctly, if Board was good, fan wouldn’t have turned on correct?

On a call for heat, the furnace control board operates the fan on a heat cycle. The “g” would be used for thermostat on/auto setting. The “g” terminal sends fan power when using the air conditioner. With that style of stat, its setting allows furnace control board to control fan, not “g” terminal.

 

[Caliguy]

On a call for heat, the furnace control board operates the fan on a heat cycle. The “g” would be used for thermostat on/auto setting. The “g” terminal sends fan power when using the air conditioner. With that style of stat, its setting allows furnace control board to control fan, not “g” terminal.

That’s what I’m hearing as well, so the above tests aren’t actually true.

So far:

New thermostat
New flame sensor
New gas valve
New air filter
New capacitor
Burners cleaned

Inducer fan operating
Blower fan operating
Pressure switches operating

At this point what else can it be? Lol

Faulty wiring somewhere or bad board

 

[mantronics]

That’s what I’m hearing as well, so the above tests aren’t actually true.

So far:

New thermostat
New flame sensor
New gas valve
New air filter
New capacitor
Burners cleaned

Inducer fan operating
Blower fan operating
Pressure switches operating

At this point what else can it be? Lol

Faulty wiring somewhere or bad board

Sounds like a bad fan relay on the fan control board. Unfortunately the relay is soldered on the board, so whole board needs replacing

 

[XX4XEXX]

Your sidetracked again. To answer your question NO. Stat set to auto heat set and energized G disconnected at furnace or t strip no fan can not come on and is what @Mantrosaid.

all your tests proved your board is bad period. Fan can not run if G is discoed at furnace no matter what, fan and everything else is a slave to the board stat is the brain persay. No stat no run. Jump out at furnace only what you jump will run.

e.g. jump out Y for cool but leave G discos fan will not run.

You keep relisting everything you replaced and I answered you. Remove G At source if fan runs and you jump out Y or W board is bad

Is it possible the fan would turn on with thermostat set to Heat and fan to Auto and G wire disconnected at furnace terminal of the board is good?

 

[Tgs]

Watched your latest video. This seems like you are tripping the high limit switch which is causing the furnace to go into shutdown and initiating the cooling cycle. I'm not sure if a bad high limit switch can cause your issue or not.

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