# Replacing furnace control board, need assistance, pics inside



## AdRock (Dec 4, 2008)

I'm replacing the HSI control on my furnace and need some assistance with switching over the wires. Some connections are labeled the same but some aren't.

I've attached pics of the two boards. I'm removing a Honeywell ST9101A-1014 board and replacing it with a Protech 62-24084-82.

On the Honeywell I have connections labeled:
Heat
Cool
M1
M2
Acc
S
N - two of them
X
C

On the Protech the connections are labeled:
Heat
Cool
M1
M2
Fan
Com
Sec
Neautrals - three of them
Then under a label that says L1 there are two blades and it looks like it says XFMR under one and PRI under the other.

So besides the ones that match I don't know where to attach the others. Any help anyone can give me would be much appreciated.


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## mrairflow (Oct 25, 2009)

looks like you got a universal board ,heat ,cool are blower speed taps m1 m2 are unsed blower taps fan will be unused also need blower neutral .L1 should come from door switch and also go to transformer will be primary or high voltage and secondary will be low voltage coming from transformer .it might be time to call a service tech ,also the board should have some instructions .


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## HVACTECH96 (Oct 16, 2012)

Potech board looks like it is for a ruud/rheem unit, with hsi ? What are you working on ?


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## beenthere (Oct 11, 2008)

Might help if you told us what wires were connected where on the Honeywell board.


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## jagans (Oct 21, 2012)

*Different Board???*

Im sure you are already thinking this yourself, but why in gods name didnt you get an exact replacement with all the same connectors, labeled the same?

Also, the control board controls a lot of stuff, not just the HSI. 

I hope you took pictures before you took out the board, and labeled where every wire went on the old board. 

In an effort to help, there should be a wiring diagram on the site where you bought that board, and the board should have included instructions.

I see that a couple of pros are trying to help you, but you have to give them more info to get a good answer


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## AdRock (Dec 4, 2008)

HVACTECH96 said:


> Potech board looks like it is for a ruud/rheem unit, with hsi ? What are you working on ?


It's a Ruud Upflow unit model UGDG-075AMGR



beenthere said:


> Might help if you told us what wires were connected where on the Honeywell board.


I posted a pic below of the board and another of the wiring diagram for it, it's still installed



jagans said:


> Im sure you are already thinking this yourself, but why in gods name didnt you get an exact replacement with all the same connectors, labeled the same?


I was told that the Protech board superceeded the Honeywell board.



Some more info:

The original problem is that the indoor blower motor won't shut off.
So far I've done:
- Replaced batteries in digital programmable thermostat.
- Verified that the fan ALWAYS ON function on the thermostat is NOT engaged
- Removed thermostat & fan still runs
- Made sure that the thermostat is telling the fan to shut off
- Replaced the limit switch with a new Protech 47-25349-02 replacement

Then I happened to see a small spark flash through the small vent hole in one of the relays. From what I can tell it's the relay that controls the fan. So I then bought the Protech Board since the relays aren't removeable.

The third pic down is the instructions that came with the Protech board. The only diagrams it has are for twin furnace systems and even on those it only shows where to hook the wires coming from the thermostat. 

As said before, all help is appreciated and if anymore info is needed just ask.


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## AdRock (Dec 4, 2008)

After sitting here and really checking things out here's what I see. Tell me if I'm way off base.

On the Honeywell I have wires connected at:
Heat
Cool
M1
M2
N - two of them
S
C
X

So this is what I'm thinking.

*Honeywell* *Protech*
Heat ----> Heat
Cool -----> Cool
M1 -----> M1
M2 -----> M2
N -----> Neutrals
S ----- SEC
C ------> COM
X ------> XMFR at the L1 location


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## ben's plumbing (Oct 6, 2011)

I mean no disrespect...thats and older rheem...maybe 1990.... is that a standing pilot model..it sure looks like it...get a different board iam not real sure that will work...ben sr..


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## AdRock (Dec 4, 2008)

ben's plumbing said:


> I mean no disrespect...thats and older rheem...maybe 1990.... is that a standing pilot model..it sure looks like it...get a different board iam not real sure that will work...ben sr..


No disrespect taken. I understand the suggestion to get a different board. The problem I have is that this pro tech and the Honeywell that super cede mine have the connections labeled the same. So even if I get another board I'm still in the same boat I'm in now.


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## raylo32 (Nov 25, 2006)

I am not in a position to say one way or the other but find it interesting that the source you bought the new board from spec'ed one that clearly has an automatic electronic ignition function for a furnace that appears to be a standing pilot. I guess it could happen but seems very odd to me....


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## AdRock (Dec 4, 2008)

I had somewhat the same question. The answer I got was that both newer boards were made to work in older as well as newer systems depending on how they're hooked up. And from all the research I've been trying to do I keep getting that answer. If that's not the case then I guess ill go from there and see what I can do.


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## beenthere (Oct 11, 2008)

Some of the older Rheems did use an intermittent pilot. How many individual wires are there connected to the gas valve.


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## mrairflow (Oct 25, 2009)

mabey this would be better 
http://part-s-mart.com/honeywell-st9101a1014-fan-timer-control-board.html


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## AdRock (Dec 4, 2008)

mrairflow said:


> mabey this would be better
> http://part-s-mart.com/honeywell-st9101a1014-fan-timer-control-board.html


I will be buying that sr9120U 1011. 

Thanks to my cats getting right under my feet I tripped and landed knee first right on top top of the pro tech board. Its toast. That's 140 down the tubes.


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## Chimmy (Nov 18, 2012)

*Dear Lord why? Do you know Honeywell or Robert Shaw Grayson sell*

a complete retro fit kit a monkey can install for $300 and it includes a new gas valve, a new ignition module a new ignitor and pilot assembly!
It all goes together and has a quick snap harness as you should have for that retro thing you are Frankensteining! !st off there are 2 plugs on the new one and 1 on the old, wheres your harness that should make this easy?

The retrofit kits essentially refurbish the entire furnace brains and heart! and all you do is wire White and Common and a Red 24v hot leg and plug in the harness and wire 120v to it


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## Chimmy (Nov 18, 2012)

*The 2 boards are not compatible*

The 2 boards are not compatible


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## Gorbechauve (Jan 26, 2016)

*ST9101A Honeywell board timer*

Looks like some of these posts are quiet old, not sure if anyone is still following.

I just replaced the my ST9101A Honeywell board in my Rheem furnace. The board was slightly diff but straight forward to switch over.

One thing I noticed was on the original board it appears as if the (M1)YL & (M2)BL wires are reversed. I am guessing YL=Yellow and BL=Black. It will have been running like this for years since we purchased this home. I hooked up the new board exactly as the old wires were connected.

I am concerned however that it has been hooked up wrong, not sure what the implications are or what could go wrong further as a result.

Any one have advice for me?

Mike.


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## beenthere (Oct 11, 2008)

M1 and M2 are park terminals. Just a place to put the wires that aren't used. So they don't hang freely and short out to anything. There is no power going to those terminals. So doesn't matter what wire was on which post.

You probably have a red and a blue wire, 1 going to cool and 1 going to heat.


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## Gorbechauve (Jan 26, 2016)

*ST9101A Honeywell board timer*

Thanks, I'm quite impressed with speedy response

Yes, I had a blue and red wire just as you say.

Mike


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## Qich77 (May 6, 2018)

I am also replacing Honeywell ST9101A-1014 board with the same part number as the original.

There is one small difference. The new board has a dip switch to set the blower delay. The board came with a sheet which documented what delay should be set for the different boards, but no chart for how to set the switches for the various delays. So far I have not been able find the dip switch settings chart.


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