Harman PF100 furnace

Figures !! Stove has black and new one is red !
Thanks I'm glad I seen this lol nice to avoid issues thanks again

 

well, you can still use the red wire probe, just make sure to flip switch 5 on (if you had a black wire probe, it will be switched off)...each probe does something different- I believe that when the heat increases on the black wire probe, the resistance decreases, and when the heat increases with the red wire probe, the resistance increases....so, the CB reads the signals and misinterprets them if the switch is wrong. So, lets see....with a red wire probe and the switch 5 set to off, the board thinks the temp is decreasing, and will feed like heck to increase the heat, so, overfeeding. And with a black wire probe and switch 5 turned on, the stove expects to see the resistance increase as heat increases, when it actually does the opposite.....man, now I am confusing myself! anyhow, red wire probe = switch 5 ON, black wire probe = switch 5 OFF

 

Thank you!!!! now to find said switch #5 I assume it's on the CB ?

 

yepper
There will be a series of little toggle switches all together with different numbers to them.
the red long box is where they are, should be the same if different color.

 

as example only!

 

just be VERY CAREFUL! The one switchblock for the PF100 here is for a D revision board, with a red wire probe. If you don't have finned ignition, or if you don't have a D revision board, your switch settings very well may differ!

 

Thanks guys .. before I do anything I'll see witch CB it has

 

Well it's looking like my CB must be bad , changed the probe .. still won't shut down even with T-stat set at lowest setting. When I switch to OFF position status light go out but continues to feed.
Only way I can get it to shut down is to unplug feed motor. Grrr

 

Do I need a special CB ?

 

LW will chime in, he's the Harman guru
Might need your serial # on hand in case he asks
If you can post your existing CB model #, you might get a faster response

 

yea, new CB....that's the next step. A local dealer should be able to nab one for you, as long as you have the serial number.....some PF100's came with finned ignition (most common), while some had pressure ignition.

 

I was afraid you was going to say that ....
Figured it wouldn't be easy enough to just order one... thanks

Ser# 008352108

 

just bring the number to the local guy....Ive no resources here at home to look up the serial number, I'm afraid. But, armed with the number, you should be able to get one fairly easily.

 

Just got off the phone with dealer , they are telling me there is only one option for a board for p100/p105.. you just have to set dip switches to your model....?

 

yup......but you need to know which ignition system you have, in order to set the switches correctly. Be sure to read the diagram completely, as well as the notes...they are important! You will get a set of switch settings with the new board, as well as knobs.

 

Update .... about to pull my hair out grrrrrr
Ok changed and performed the following.
New probe
New circuit board
New combustion blower.
Removed chain shaker door while I had blower off cleaned everything I could get to, resealed everything.
Cleaned entire rest of furnace,its squeaky clean now.
Fired up and ran perfect, let it work for couple hours..... turned t-stat clear down,,, furnace still will not shut down,
Not even when I turn switch on OFF.... status light gos out when turned off but it still feeds fuel.
I'm getting no status blink light.
Anything else to try ??? I'm about to throw it away and put the quad back in

 

How long did you wait after you turned the stove off? Harmans will continue to feed after being turned off if the stove was really cranking. They feed at a reduced rate until the temp comes down then will go into shutdown.

 

A good 3 hours
It takes my 45 about a hour once you turn it down .. there's something stupid going on with this furnace I'll bet it's something simple ....

 

Yup, there is.

 

I've almost convinced my self the feed rate is to high at idol...
At idol it gets hot enough to cly the blower , I've played with feed rate and temp dial dosnt seem to make any difference?
Blower controller is set to come on @ 150* off at 100*