Payne Furnace Pains - Updraft/downdraft Parts Swap?? - HVAC - DIY Chatroom Home Improvement Forum


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 12-12-2011, 06:26 PM   #1
Newbie
 
Join Date: Dec 2011
Posts: 1
Rewards Points: 10
Unhappy

Payne Furnace Pains - Updraft/downdraft parts swap??


Payne 100FAU-12 100k BTU natural gas furnace (Payne #1)
Initial Problem: Furnace gas supply to burners in runaway condition (would not shut down) causing a strong "burnt" odor through house. Thermostat set to coldest temp had no effect, blower still working. Shut down furnace by turning off gas supply valve.
Gas utility called to inspect. When lighting pilot, discovered gas to burners still flowing full so gas man disconnected supply and left, saying furnace probably should be replaced. Subsequent tests indicates that transformer works but the limit switch is likely toast (no continuity between terminals when cold).

Due to severe economic situation we can't afford a new furnace or even a service call. Found a used 100k furnace that had been replaced only for increased efficiency for $50, so sent a friend to pick it up. Call this Payne #2. Upon delivery it was discovered that while it appears to be in excellent condition, it is a downdraft design and the failed 100FAU-12 is an updraft. Single story home was built in 1966 and has only 2 floor located cold air returns.

The failed unit (Payne #1) is so old that I cannot locate manuals or schematic for it. It uses a Unitrol 12005VER gas valve with only 2 electrical connections, and one inline thermal limit, that in my limited experience looks similar to a valve for a hot water heater and requires a pilot to be lit all the time. One other thermal switch is adjustable as to air temp before turning fan on. I assume that this valve is stuck in the open position as gas flowed to burners when the knob was turned to "Pilot" and depressed. This furnace uses 2 individual burners to heat the chamber whiich does not have any visible cracks in spite of possible overheating.

Recently purchased used unit (Payne #2) is Model # 396GAW has a much more complex control scheme using a door switch, control board with relay, 2 limit switches and a pilot light ignitor. The somewhat larget gas valve has 5 electrical terminals vs. the 2 on the original. I also have a readable schematic on the inside of the service door. This unit uses 4 burners.

Realizing that my initial thoughts of swapping the furnaces won't work, I'm left with the idea of swapping the controls and gas valve from #2 into #1. While it may be possible to replace the failed limit swith and the stuck valve in #1, I just don't have the finances to do that. I will need to drill a few holes for controls mounting and for the additional limit switch,

Are there any major problems that I'm not seeing in swapping out the valve and controls?

Adding to the urgency is the fact that there are 7 adults and 2 children currently living in this small home and it's getting rather cold here (Northern CA). We do have a wood stove that is able to keep the place warm enough for sleeping but that's going to get worse as winter sets in.

Thanks in advance for your assistance, experience and suggestions,

"Stick"

Advertisement

sticknca is offline   Reply With Quote
Old 12-12-2011, 09:11 PM   #2
AKA HVACTECHFW
 
Join Date: Nov 2010
Location: NE Indiana
Posts: 2,368
Rewards Points: 1,100
Blog Entries: 1
Default

Payne Furnace Pains - Updraft/downdraft parts swap??


asked and answered NO!

Advertisement

__________________
IT IS WHAT IT IS
hvactech126 is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Lennox Furnace G27M Series Unreliable operation: pressure switch or else? sheppard1977 HVAC 7 01-14-2013 06:42 PM
Payne furnace -- Error Code 12 orcaboy HVAC 22 03-11-2011 06:18 PM
Problems with new furnace..Overheating, having to reset. Furnace too big? Tommy2 HVAC 41 12-01-2008 02:55 PM
New Cased Coil - Install to Furnace - PICTURES!! hartkem HVAC 39 11-18-2008 02:45 AM
Burner won't fire on Payne 490AAV furnace lwhpops HVAC 2 10-20-2006 04:03 PM




Top of Page | View New Posts