Second Stage not working New install.

[chill factor]

I recently installed a Keeprite M#C9MPT100 High Eff. 2 stage furnace with 2 stage t/stat. I converted it to propane with the recommended kit.
My problem is, when i jump R,W1 & W2 together the ventor motor goes into low speed and lights off on low fire. It stays on low fire and never gets to high fire.
I removed all t/stat wires from board and placed it into data mode. It still only fires on low fire and ventor motor is on low speed. A keeprite rep says once it is in data mode and high fire does not light the problem is the valve.
I feel he is incorrect just by looking at the schematic, the power to the ventor motor is coming from fan board. Data mode sends signal back to board and i believe the board is supposed switch high speed ventor and look for a proven high speed and light off on high fire. I think its the board but the rep says the valve. Any help greatly appreciated.

[Christheheatingdude]

On some models it will not go to second stage when both W1 & W2 are energized on start up. And there could be switches that need to be set, are you using a single stage stat?

[chill factor]

Dude, I wrote i installed a 2 stage stat. I jumped W1 & W2 at the fan board.

[Christheheatingdude]

chill out chill factor

sorry I missed that in your original post.

On some furnaces, regardless of if you have W1 & W2 jumped, if it happens at the same time or you jump them before you power the furnace, it will stay in first. I have had to start it on a call for first stage heat only, then jumper W2 to go to high. How long are you waiting for it to go to second stage?

[seatonheating]

Heating dude is right about some furnaces not high firing initially with w2 energized. Not sure if this is the case with your furnace, but maybe you should wait the 10 minutes or whatever the delay is and see. If then it fired, my guess would be the stat.

[chill factor]

I installed another 2 of the same furnaces and during set up I did the same thing W1,W2 & R were jumped with power off and then turned power on and right away I got high fire and high speed ventor motor.

[BaldLoonie]

I've never touched an ICP 2 stage. But Trane is as dude says. If you energize W1 & W2 together, the board reacts as if you have a single stage stat and uses the timer. But after 10 minutes it times to high. I have no idea if ICP does it this way or not. Rheem doesn't.

Is this a Smart Valve system? That would make it a challenge to diagnose.

Maybe hvacprodmgr would have some ideas. Don, you reading this?

[tinknocker service tech]

it would seem to me if the draft inducder is not going into high speed the high fire presure switch will not let the valve go to high fire. check your settings on the board
or try to sequence first stage then second stage. icp may have made changes in the borad and it is locking out second stage

[chill factor]

Yes it is a Smart valve.
By placing the system into Data mode(jumping the 24 & data wire at smartvalve) its supposed to go directly to high speed ventor and high fire. Prior to Data mode it is required that all t/stat wires are off of the fan board. I still get low vent & low fire.

[Black Adder]

Did you install a low pressure switch on the gas valve. I just installed the exact same unit as you did this week. I used a 1 stage tstat and let the unit do it's own thing. Unit starts in high fire and then after 2 minutes drops to low fire for the next 10 minutes then back to high fire if the tstat is not satified. I just returned from a dealer meeting and there was some talk about problems with firing to high on propane. I will talk to my Heil tech guy on Monday and post his reply if you have not figured it out yet.

[Milk man]

I just want to tag along. I know nothing about this furnace.

Have you tried to run some stat wire out of the cabnet and cycle the low and high fire with jumpers. In other words. wire the board with pig tails, power up the furnace, jump W1 let it start and then jump W2.

AND, holly crap, a two stage SmartValve! SmartValves, what a cluster.....

[Black Adder]

Try setting the dip switch #4 to the on position and then just jumper r, w1 and see if it will do a fire on high on the furnace timer, that will tell you if the valve is ok. If not I would say it is the board.

[mayguy]

Originally posted by chill factor
installed a 2 stage stat. I jumped W1 & W2 at the fan board.

?? Is this the way they do thier wire??

How would it know if it's needs 2nd stage or not?

The way it's wired above, the w1 will feed the w2, and go into high fire right away...


I agree with Bald about some won't fire into high fire if w2 gets the power right away and till go for time.