1993 Comfortmaker RPG II Flame Sensor Not Working?

Northwoodslakes · 08-28-2012, 08:27 PM

Quote:

Originally Posted by Doc Holliday

I only kind of glanced through this thread thus far, only now seeing that the problem was only after you changed the transformer. What was the problem before, why did you change the transformer?

I burnt out the old Transformer while using a test probe/w wire alligator clip on some of the Thermostat terminals on the Board, and being a Novice I toasted the old Transformer. Do any of you guys think I may have harmed the internal circuitry inside the Control Board for the Flame Sensor as well while doing this?
(I know I toasted the Transformer because of the obvious smell, so I replaced it and the AC worked just fine, but now I'm always having the Flame out)
Thanks for your help!

Doc Holliday · 08-28-2012, 08:27 PM

I said I'd start there as electronics and electricity look good on paper but in actuality can be very moody, touchy feely, highly sensitive. I would at least give it a shot but you're right, it should work.

Again, why did you change the transformer in the first place?

Doc Holliday · 08-28-2012, 08:28 PM

Quote:

Originally Posted by Northwoodslakes

I burnt out the old Transformer while using a test probe/w wire alligator clip on some of the Thermostat terminals on the Board, and being a Novice I toasted the old Transformer. Do any of you guys think I may have harmed the internal circuitry inside the Control Board for the Flame Sensor as well while doing this?
(I know I toasted the Transformer because of the obvious smell, so I replaced it and the AC worked just fine, but now I'm always having the Flame out)
Thanks for your help!

How, I'm done with this guy. You can have at it.

Northwoodslakes · 08-28-2012, 08:36 PM

Quote:

Originally Posted by how

We've been basically getting you to test out other simple possibilities instead of just changing your 50A50-112, but as "Doc" suggests, it's probably time to take the plunge.

A pro at this time would be
confirming the DC milli amp of your flame sensor when the gas is burning.
checking if the 50A50 is even powering the flame sensor.
and making sure the gas valve is not still getting 24V after the furnace gas shuts off.

"how" I have a meter, but of course a novice. Can you tell me what and how to use it. I know how to set the dial for 120V ,and you have the 2 probe leads, one black, one red. Obvoiusly the One probe end goes on the Sensor Rod wire connection and the other end goes where? That plug where the Flame sensor wire goes into the Control Board is impossible to get anything to touch it. Is it too complicated to explain to me?

Thanks in advance "how"

Northwoodslakes · 08-28-2012, 08:43 PM

Quote:

Originally Posted by Doc Holliday

How, I'm done with this guy. You can have at it.

Hey, Doc, I told you guys I'm a NOVICE when it comes to electrical stuff! I'm learning from you folks! I appreciate all I can learn from all you experts!
You guys have solved many a problem, but mine seems more involved? I've done everything that has been suggested.
DO you guys think I may have toasted the Board when it comes to control of the Flame Sensor?

Northwoodslakes · 08-28-2012, 08:56 PM

Quote:

Originally Posted by how

We've been basically getting you to test out other simple possibilities instead of just changing your 50A50-112, but as "Doc" suggests, it's probably time to take the plunge.

A pro at this time would be
confirming the DC milli amp of your flame sensor when the gas is burning.
checking if the 50A50 is even powering the flame sensor.
and making sure the gas valve is not still getting 24V after the furnace gas shuts off.

"how" please don't jump ship on me like "Doc" did so quickly. If you can explain how a pro would test, I do have a Meter and would really like to try this before replacing the Control Board. You are exactly right, This sounds like what I really need to be doing. Do m just attach one probe end to ground and the other to the electrical connector on the Flame sensor? Then what do I look for in the Meter when it fires?
Is it too much to explain? I hope you can try, this will be the determining factor as you say. I think it is most likely the Board and would like to test it, if you can explain easily enough?

Thanks in advance.

how · 08-28-2012, 09:10 PM

It takes very little of a voltage surge to damage electronic boards.
Your probe mishap with the transformer "experiment" could easily damage a 50A50.
I think the directions for doing a DC milli amp test on the flame probe circuit is questionable given your experience and probable test equipment.

Your reasonable options are

guess that the 50A50 is faulty and change it. (not with a used one)
or
get a pro to test it all & change what is needed.

This is not a good project for a novice to get involved with because of the safety issues and the additional expenses that your experimenting might cost you.

Northwoodslakes · 08-28-2012, 09:25 PM

Quote:

Originally Posted by how

It takes very little of a voltage surge to damage electronic boards.
Your probe mishap with the transformer "experiment" could easily damage a 50A50.
I think the directions for doing a DC milli amp test on the flame probe circuit is questionable given your experience and probable test equipment.

Your reasonable options are

guess that the 50A50 is faulty and change it. (not with a used one)
or
get a pro to test it all & change what is needed.

OK, "how" Thanks for your response. The furnace is 1993 vintage. A brand
new Board is expensive, and I don't believe this Furnace is even worth it. I will spend the $70.00 and get the used one from a reputable seller and exchange my Board with it. I'm thinking from all you've tried to teach me and yes I tried all things. I most likely fried it like you said.
Then if that does not work. I will hire a Pro and replace the entire Furnace. Perhaps time has come. I'm not going to throw good money at an Old Furnace. I think a new Board was like $300.00.
So thank you for your wisdom and expertise. (I certainly wish I knew more about the ins and out of electrical, but NADA) Thank you Friend!

**beenthere** · 08-28-2012, 09:25 PM

Common of the 24 volt side.

Northwoodslakes · 08-30-2012, 06:47 PM

Quote:

Originally Posted by how

It takes very little of a voltage surge to damage electronic boards.
Your probe mishap with the transformer "experiment" could easily damage a 50A50.
I think the directions for doing a DC milli amp test on the flame probe circuit is questionable given your experience and probable test equipment.

Your reasonable options are

guess that the 50A50 is faulty and change it. (not with a used one)
or
get a pro to test it all & change what is needed.

This is not a good project for a novice to get involved with because of the safety issues and the additional expenses that your experimenting might cost you.

OK guys, Doc was right, I researched and found a universal replacement Board, the White Rodgers 50A55-843, brand new one for only $74.00. I appreciate all the great input from you guys on this DIYBoard. But please assure me that I do have the right replacement Board, (I've read on a few sites that maybe it isn't compatible? You read all kinds of crap on the Internet.) But I mostly have read it is and will be an easy install. Thanks to you in advance!! I will be so glad to get this aggravation fixed once and for all. What do you think "how"?

I was so amazed to find this new Unit as you suggested. Only 74 Bucks!

Doc Holliday · 08-30-2012, 07:03 PM

That is correct.

http://part-s-mart.com/white-rodgers...rol-board.html

**beenthere** · 08-30-2012, 07:15 PM

Don't install that board. If you do, a nuclear power plant in China will blow up. Its a secret weapon invented by the KGB back in 1994. LOL... Just kidding around.

Doc Holliday · 08-30-2012, 07:51 PM

That was just terrible, BT.

danpik · 08-30-2012, 08:19 PM

Quote:

Originally Posted by Northwoodslakes

What about the fact that the Burners stay on for approx. 5-6 seconds before flame out without the Sensor wire attached?

This is a design feature for the control board to allow the gas valve to open to light the burners so it can "see" the flame sensor. Without it allowing this it would never light. This is simply a timer in the control board. You indicated that the ground wires are hooked up in the junction box...are they all connected back to the main panel? Set your meter to Ohms and see what the reading is between the burner tube and the ground wire in the junction box. It should be the same as if you connect both meter leads together.

ben's plumbing · 08-30-2012, 10:43 PM

Quote:

Originally Posted by beenthere

Don't install that board. If you do, a nuclear power plant in China will blow up. Its a secret weapon invented by the KGB back in 1994. LOL... Just kidding around.

hey bt thats just not right..lol

but i liked it..

08-28-2012, 08:27 PM	#47
Doc Holliday I'm Your Huckleberry Join Date: Mar 2011 Posts: 5,216	1993 Comfortmaker RPG II Flame Sensor Not Working? I said I'd start there as electronics and electricity look good on paper but in actuality can be very moody, touchy feely, highly sensitive. I would at least give it a shot but you're right, it should work. Again, why did you change the transformer in the first place? __________________ Thanks.

08-28-2012, 09:10 PM	#52
how Member Join Date: Feb 2011 Location: Vancouver BC Posts: 1,416	1993 Comfortmaker RPG II Flame Sensor Not Working? It takes very little of a voltage surge to damage electronic boards. Your probe mishap with the transformer "experiment" could easily damage a 50A50. I think the directions for doing a DC milli amp test on the flame probe circuit is questionable given your experience and probable test equipment. Your reasonable options are guess that the 50A50 is faulty and change it. (not with a used one) or get a pro to test it all & change what is needed. This is not a good project for a novice to get involved with because of the safety issues and the additional expenses that your experimenting might cost you. Last edited by how; 08-28-2012 at 09:25 PM.

08-28-2012, 09:25 PM	#54
beenthere An old Tradesmen Join Date: Oct 2008 Location: PA Posts: 19,057	1993 Comfortmaker RPG II Flame Sensor Not Working? Common of the 24 volt side.

08-30-2012, 07:03 PM	#56
Doc Holliday I'm Your Huckleberry Join Date: Mar 2011 Posts: 5,216	1993 Comfortmaker RPG II Flame Sensor Not Working? That is correct. http://part-s-mart.com/white-rodgers...rol-board.html __________________ Thanks.

08-30-2012, 07:15 PM	#57
beenthere An old Tradesmen Join Date: Oct 2008 Location: PA Posts: 19,057	1993 Comfortmaker RPG II Flame Sensor Not Working? Don't install that board. If you do, a nuclear power plant in China will blow up. Its a secret weapon invented by the KGB back in 1994. LOL... Just kidding around.

1993 Comfortmaker RPG II Flame Sensor Not Working?