setback thermostat tech bulletin

[caralck]

There's multiple repostings about this tech bulletin but is there a way to actually get a copy of this bulletin that was released in 2007? We're planning having an electrician come out to help us run the wiring from the stove, under the house in the crawlspace and back up through the wall to reside next to the gas furnace thermostat (a friend of ours did that with their nonharman insert). Figured it would be good to have the actual bulletin (with pictures hopefully?) to help us out. And since my accentra has the auto-ignite, I'm guessing that the 4-blink status resolution would just allow the stove to go back on. Only other question is that if we don't do it this way, how does one extend the wire to just have the probe off the stove itself? And where exactly is the probe?!? We also thought that if we didn't do another thermostat, maybe just run an extended wire along the junction where the brick fireplace meets the drywall. I imagine just getting the end of the probe off the stove would help with the room temp setting.

 

[AVIVIII]

I did something similar with my Harman, I was not able to find the actual bulletin either, but it was easy to figure out.

I'm on the road for work right now, I'll see if I can get my wife to take some pictures and I'll put them up.

Meanwhile, I'll try and offer some insight.

The first post on this https://www.hearth.com/econtent/index.php/forums/viewthread/7790/P0/ thread has the specifics that you need to consider.

First off, yes, the stove will re-ignite when the t-stat calls, which will take care of the 4-blink.

HOWEVER... Your success with this modification will vary on how you intend on using the stove.

Using a digital, set-back t-stat as it is intended on being used may not offer the result you are looking for.

To begin with (most of this I'm sure you know), using the room temp sensor requires the stove to be run in Room Temp mode, for which the thermostat is set on the stove computer board. The room temp sensor and stoves computer do a very effective job at maintaining a constant room temp, assuming proper placement of the sensor. (Despite your dealer/installers recommendation, hanging off the back of the stove is NOT a good place for it, there are too many variables in play; simply moving the sensor 3 feet away will greatly improve the stoves performance in Room Temp mode. )

Since the Harman t-stat is internal and dependent on the input of the room sensing probe, all we are able to do in interrupt the signal, causing the stove to believe that the sensor is unplugged and go into shutdown (4-blink).

If you intend on using it as a real set-back t-stat where at one time, you want the room at, say, 65 and then at another time you want it to increase the temp to 80 and back again, we need to look at what is happening with the stove, the igniter and the t-stat. First, for the room sensing probe circuit to be active, the stove needs to be in room temp mode. The temp on the stove "Room Temp" dial should be set to the highest of the temperatures in play, for this case, 80. When the t-stat allows the stove to burn, regardless of what temp the t-stat is set at the stove is going to try and get the room to 80. To actually achieve this effectively, the t-stat should be set to its MAX setting (usually 90). At this point, it is allowing the stoves computer to be in control. The roll-back (65) set on the t-stat is when it is going to get interesting. If the igniter is in Auto when the t-stat rolls back, the stove will go into 4-blink and shut down until the t-stat calls again, at which point the stove will re-start, re-ignite and burn, trying to get the room to 80, until the room reaches 65, satisfies the t-stat, breaks the circuit and puts the stove back into 4-blink. Now I don;t know about your house, but in may house, that would be a lot of starts and stops. If the igniter is in manual mode and the t-stat rolls back, the stove will go to min burn, until the t-stat calls again. If you are going to burn 24/7, this is probably the mode for you.

To answer the rest of your questions, you can simply cut the supplied probe wire and splice in up to 50 feet of regular 2-strand thermostat wire. They seem to recommend 24ga, though I am using the larger 18ga with no problems. The probe should have come with your stove and is a 6' piece of wire with a coated tip on the end, it just plugs into the back of the stove.

Just remember in all of this, you are running the set-back t-stat IN SERIES with the room sensing probe and the probe still needs to be present in the circuit for this to be effective. What this means is that you are going to have to wire the t-stat in kind of an abnormal manner. Using the Rh and W terminals, you will use the red wire from the thermostat wire AND the red wire from what is left on the probe. I don't think it matters which one goes where, it is simply breaking the circuit. The other wires (usually white or black) get tied together to complete the circuit.

This will probably make more sense with Pics, but the wife is in bed, so they will have to wait till tomorrow. FWIW, I run my set-back t-stat as a timer, it turns the stove on before the wife comes home from work and shuts it off before she goes to bed. It is always set on 75 and does a great job.

 

[FordMastertech]

Not sure what stove your running but on my Quad AE I hard mounted the thermostat in the entrance to the living room, right next to the thermostat for the main house heating and cooling. The stove is on the other side of the house in the family room but the warm air blowing throughout the kitchen was short cycling the stove a lot. What I did to find the best place for the thermostat was to extend the wire and tape the thermostat to the wall in different locations in the first floor of the house. In the living room a large window faces south so I get winter heat gain in that room. The Quads thermostat sensed this and I found the rest of the house cold when it was mounted in this room. I finally found the front foyer the best location right next to the open side of the stair case. The cooler air from up stairs helped to keep the thermostat from short cycling. It took several weeks to come up with this location by trial and error. My wife thought I was off my rocker and then knew it when she found me walking around with a stick of burning incense watching which way the smoke would travel by the air currents. I recommend to try this method before drilling walls and running wires.

 

[caralck]

Oops, probably should add the stove info into my sig. It's a harman accentra insert.

 

[caralck]

Well, other than updating my profile so my stove info is in, I looked through the installation portion of the manual and realized that we were never given the option of whether or not we wanted our room temp probe to be on the stove or off of it so I first contacted Harman by email last night and then called the our dealer this morning. Next friday we'll have them come out and get the room temp probe wire to come off the stove and they also confirmed that a wired thermostat can be used with it and offered to install one next to the stove but I think we'll first start with just having the wire off the stove and see if that allows us to have better success with room temp mode. If that's all it takes, then we won't bother doing the thermostat right away

 

[AVIVIII]

Before I wired up the t-stat, we had the probe hanging off the back of the stove, as suggested by the dealer/installer. It did not work well at all. By simply uncoiling it and taping it to the window trim 4 feet away did wonders, now having it across the room, about 18' it works perfectly.

 

[caralck]

Do you know how long of an extension wire can be used? Or does that not matter? Good idea about checking the different locations. I'd hate to go through the effort to run the wire under the house and back up only to find out that it doesn't work out. Short circuiting the stove does not sound good at all! Where do you get the extension wires, by the way?

And how long is the room sensing probe that comes with the insert?

 

[caralck]

Shameless bump on this one. I had read somewhere on here that only 25 ft is the max extension...anyone?
Also, are the 2 thermostats recommended the only ones that can be used? Has anyone successfully put a gas furnace and their harman on the same thermostat? Or is it something to just not do?

 

[summit]

Do you know how long of an extension wire can be used? Or does that not matter? Good idea about checking the different locations. I'd hate to go through the effort to run the wire under the house and back up only to find out that it doesn't work out. Short circuiting the stove does not sound good at all! Where do you get the extension wires, by the way?

And how long is the room sensing probe that comes with the insert?

use regular tstat wires. probe's factory length is about 6 ft.

 

[caralck]

Guess what I just found in the bag with the paperwork for our stove? The room sensing probe! Does it come with one or 2 of those? If only one, then it appears they didn't even put the probe on at all!