[tfunk]

Hi all!

My furnace never goes into high fire. It's a mid efficiency two stage furnace. It'll go on low fire for a given amount of time then the gas fire goes out and the blower goes on higher/louder for about a minute and then it switches off and restarts the process on low fire of course.

We are just north of the perimeter in Winnipeg.

Cheers,
Tyler

 

[Missouri Bound]

Model numbers would be nice, mfg. as well. Just start happening...always like this, new thermostat, any other problems......all answers are based on what you provide, the more the merrier.:laughing:

 

[tfunk]

Model: Rgpk-10eamer
Serial: Fq5d302f320401669
Manuf Date: 8/2004

We moved in oct 1 and it needed a new pressure switch. High fire never worked. The tech who replaced the switch noticed high fire never activated we tried some things nothing worked. One of the wires from the thermostat used to go to the furnace now it's going to the air conditioner (installed after the furnace apparently). I believe it's the wire that tells the furnace to recirculate air (my guess is the lazy air conditioner did this assuming no one uses this function). On the board itself we were putting this one wire (may have been black) into a constant "on" position (at least that's what the tech told me he was doing) to see if high fire would initiate. We were also trying to make it skip low fire and go into always high fire. We were also trying to hardcode the other wire to have the furnace always in recirculation mode. No dice!

Is this an ok start? I think that's all I can think about it.

 

[Doc Holliday]

do you have a w2 terminal on the stat that's connected to w2 in the furnace?

 

[tfunk]

No, just W, Y, RC and RH. RC/RH are on the same signal. Is W2 related to high heat?

 

[tfunk]

According to the manual, W2 is needed for high heat.... Is there a way to hardcode the terminal on the board somehow?

 

[tfunk]

hmmmm, seems to be a single stage thermostat option on middle column of page 3:
http://www.rheem.com/documents/rgpk-use-and-care-instructions

It appears high fire is possible without W2 connect? I'm lost ....

 

[tfunk]

My stat appears to be 2 stage capable but is operating in single stage mode. So probably jumpers on the board are preventing the jump to high heat. Is high fire really less efficient than low fire? That's what the thermostat manual tells me. Set the differential (when high fire shuts off) to a higher degree saves energy.

 

[beenthere]

Furnace is probably set to control second stage off of its timer. Is it maintaining temp the way it runs now? How long is its burner on time?

 

[tfunk]

It maintains temp, but going up 4 degrees can take about an hour or more.

 

[tfunk]

Also, if that's true, why does it have to recycle? Why doesn't it just stay on in low fire?

 

[yuri]

After 12 minutes the timer on the board will kick it to high fire. You need a wire from G on the tstat to the board G to run the fan continuos but I don't recommend it as it is drafty and can cost up to 1$/day to run the fan. Some newer units have high efficiency NRG saving motors but yours doesn't unless it has a 16 wire cable going to the motor. High fire should work as we get to -40C/F here and it is pretty hard to be comfortable with just low fire.

 

[yuri]

Also, if that's true, why does it have to recycle? Why doesn't it just stay on in low fire?

There is a heat anticipator/length of cycle feature in the tstat and it is maxing out due to it being on low 2 long and will start cycling the burner/itself irregardless of house temp.

 

[tfunk]

Interesting. Is there a way to have te board go into high fire on it's own? Or would you more or less say my setup is sufficient/good enough?

 

[tfunk]

After 12 minutes the timer on the board will kick it to high fire. You need a wire from G on the tstat to the board G to run the fan continuos but I don't recommend it as it is drafty and can cost up to 1$/day to run the fan. Some newer units have high efficiency NRG saving motors but yours doesn't unless it has a 16 wire cable going to the motor. High fire should work as we get to -40C/F here and it is pretty hard to be comfortable with just low fire.

So your take is that the board is already wired for high fire the furnace is just choosing not to do it currently? Or is randomly doing it when I'm not looking?

 

[yuri]

By default from the factory I believe it is setup with the jumper on the board for true 2 stage op with a 2 stage tstat. Most guys use a single stage stat to save $$ and avoid running extra wire to the tstat. Not sure what the heck your installers or techs have done. It is fairly easy to figure out if you have the install manual. Will show you the jumper position for 1 stage stat or 2 stage stat op. Some even have an option for high fire only. Not sure what you have but a skilled tech with the manual or enough experience should be able to figure it out by looking at the board. Did a 2 stage 95% for Sis not long ago. The board has letters on it for the jumpers but w/o being there I can't tell you exactly what to do. Superior Htg sold a lot of Rheems and probably has a few skilled techs.

 

[tfunk]

You still in the biz? I'd pm you but I need 20 posts to send PMs

 

[JJboy]

Best: W1 and W2 from furnace control board connected to W1 to W2 thermostat ( 2 stage )

Good: W1 from furnace control board connected to W1 from thermostat. ( control board will setup 2 stage by timing)

Worst: W1 and W2 jumped from control board connected to W1 from thermostat. You have 2 stage furnace working on high stage only.

Do you have thermostat with W1and W2?
Do you have extra wires to connect W1 and W2?
You have to check the control board switchs

Sent from my iPhone using DIY Forum

 

[tfunk]

I do have w2 and w1 on stat, even a Y2. Likely the current Y1 used to connect to w2, but now that's going to the airconditioner. I would need to run another wire for w2. I suppose I could put y to w2 and unhook the aircon for the winter.... Running another wire would probably be a lot of work.

I'll take a look tonight and see what's jumpered and where the other end of my current y1 is going.

 

[tfunk]

Seriously, though, there are only three wires from my stat to the furnace what a crapshoot install job back in 2004....