Harman XXV + Skytech 3301P = Awesome! (Added link + info relative to Harmans suggested method as wel

Below is a procedure outlined to make the thermostat the primary sensor for heat cycles - I call this concept - THERMOSTAT PRIORITY. This does not rely on the thermistor probe (room sensor) to be properly calibrated to the surroundings to insure accurate heating of the room since the thermostat determines hi/low room temperature. There is another concept - I call it STOVE SENSOR PRIORITY. You can use this concept to make the thermostat a simple set back unit and this is how Harman recommends you do it. Downside is the fact that it will take some trial and error to get the room sensor properly calibrated so setting of 70 results in a room temp of 70. In my opinion THERMOSTAT PRIORITY is easier and more accurate long term since you won't need to fiddle with the room temperature potentiometer which can be prone to degradation over time and is not as exact as a digital thermostat.

See this tread for details about the type of thermostat Harman recommends and how to get set up for the less favorable STOVE SENSOR PRIORITY - http://www.hearth.com/econtent/index.php/forums/viewthread/7790/

^^^^In either case, setting the igniter switch to manual will result in the stove going to maintenance burn while the thermostat is not calling for heat or contacts open. If you want to run in Auto mode, the stove should shut down and start up nomally. ______________________________________________________________________________________________________

Just installed the 3301P wireless thermostat and it works like a champ. Installation couldn't have been easier The folks at Skytech made it even easier than I anticipated. No cutting, no crimping, no splicing. Perfect!

Here are the install tips and a few pictures, prior to bundling and hard mounting everything.

The Skytech leads come with a female plug and an attached male plug "jumper". This makes everything a breeze.

(Harman plugs are red and Skytech plugs are clear plastic (in my case) - see pictures below)

Step 1 - Remove 1 temp probe lead (doesn't matter which one) from the Harman temp probe socket located at the back of the stove. Leave the other wire attached to the stove.

Step 2 - Break off the male portion of one Skytech control module lead (doesn't matter which one), preserving the female plug, and plug it into the slot previously occupied by the Harman probe wire.

Step 3 - Plug the remaining female lead from the Harman probe into the male portion of the remaining wire from the Skytech control module.

Step 4 - Set the room temp dial on the stove to a temperature higher than your remote thermostat will need to reach. In other words, if you plan to heat the room/area to no more than 75 degrees, set the room temp knob to 80-85 degrees to insure the thermostat maintains temperature control. You could max out the temp dial on the stove, but if the remote thermostat should have a problem one day, you don't want the stove to cook you out of the room. However, if you don't set the temp knob high enough, then the stove might throttle back before the thermostat call for heat is satisfied. After the stove has run for several hours and is up to temp, just pay attention to the thermostat and the status light on your stove. You'll always get the 4 blink status light at the end of every call for heat.

Now the Skytech control module is in series with one wire of the Harman temp probe creating a simple on/off switch for the probe. When the contacts open, the probe goes into fault (stove sees 105 degrees room temp) and the stove goes into 4 blink mode (if stove switch is on Auto or go into maintenance burn if the stove is set to manual).

The manual does a good job of explaining everything else with one exception. The swing temp is PLUS and MINUS of the set temperature. So, if your set temp is 70, then a swing temp setting of 2 will turn the stove on at 68 and off at 72. I thought it would be similar to a typical furnace thermostat where the setting would be max and the swing would be a minus only value. No big deal, just be aware before you program your temp settings. Currently, a 1 degree setting (3 degree total swing) seems to be the best balance between comfort and efficiency.

Cool, thanks for sharing the pictures and posting the step by step. Any idea where I could get a Harman diagnostic tool? That would be great to have.

Your welcome. I got the tool from my dealer. $250 shipped. Since you can't make any changes to the stove, Harman should gladly supply the tool to those who are willing to pay.

Thanks for that information. Called my dealer and they want 400.00 for one. Going to try another dealer possibly. How's that setup working so far?

Well, 250 probably is the landed cost... So they'll want to tack on a margin... 150 bucks of margin is a bit steep, but, hey, it's their business. Now that I have the programmable T-stat and have a feel for the setting I'd like to run on stove temp for the shoulder seasons, the tool is a bit of a novelty unless a problem should arise.

Likes on the tool are - ESP set point in degrees, ESP temp acutal, trim pot values for feed and temperature, room temp sensor set point, room temperature sensor actual... Also shows voltages for the fans which could come in handy in the future.

I'm sure somebody that is good with electronics could come up with a homemade box for just a few bucks. Even if you just had voltage and resistance readings it would be a help in diagnosing our Harman problems. Say X ohms = Y degrees at the esp or room sensor, or a range for the pots. ?

I'm new here and have gotten here because I have trouble controlling temp on my Harman P68. The wireless thermostat sounds great to me but I have some questions. You said it will go into 4 blink mode when it sees the fault. What will "erase ?" the 4 blink mode and allow it to re-start when it calls for heat?
Will the Skytech thermostat work on a P68 that I bought back in '05?
Thank you.

Correct, works like a charm!

Sorry, I can't say for sure. I would presume - Yes. One way to find out is to un plug 1 leg of your temp probe, get the 4 blink status, wait for 5 minutes, and plug back in. If it resets and fires back up, then you're good to go. Do this with igniter set to manual.

EDIT - The Harman bulletin from 2007 says "ALL" Harman pellet stoves...

Thanks for the great info on this thermostat. I'm intrigued by this set up but I have a question. If the stove goes a while without a call for heat, will the fire eventually go out or does the stove just go into maintenance burn mode similar to when it is set to manual ignition?

Will do either, but I have my switch to manual, so it goes to maintenance. Best part, the swing on the thermostat can be 2, 4 or 6 (total) degrees which would be easier on the igniter during shoulder seasons in auto mode.

Temp is in the mid 30's, high 20's and the basement is a comfy 72 degrees 24/7. I'm getting 1.5 days out of a 40 lb bag of "shoulder sesaon" pellets... Not bad if I say so myself.

Also, I added some information about the difference between "thermostat priority" and "room sensor" priority to the first post in this thread.

Thanks, I didn't realize that the stove would still "follow the rules" of the igniter switch while in the 4-blink mode but it's good to know that it will. Cheers!

Updated original post. There was some speculation that in THERMOSTAT PRIORITY the stove would not relight properly if igniter switch was in Auto Mode. I have verified this (I always run in manual) and the stove restarts perfectly from "cold" in Auto Mode.

Great instructions, Ibcynya! I was about ready to order the Skytech 3301P from a vendor on ebay when I got to thinking...

I already have a Lux programmable wired thermostat and the two-wire cable from my old Quadra Fire stove. The wires are all in place, ready to hook up. So if I'm understanding your installation instructions correctly, I can just use what I already have in place:

1. Unplug one of the probe wires from the back of my stove.

2. Take one of my programmable thermostat wires, put a female spade plug on the end and plug it into one of the terminals on the back of my Harman stove.

3. Take the other thermostat wire and attach it to the other Harman probe wire (the one that I just unplugged from the stove in step 1.

4. Turn up the stove room temp dial to 75 or 80

5. At that point, my Lux programmable thermostat will open & close the circuit, turning the stove off and on.

If this works it'll be great! I've been wanting to set back my temp during the night hours, and I didn't realize I could just hook my programmable thermostat that I used on my previous pellet stove.

Sounds like a winner. Since you say it's a 2 wire from the old stove, I assume it's millivolt compatible. If so, you should be fine. To start, turn the room temp knob to max, just to make sure all is working correctly. Then you can dial the room temp down a bit. I like to keep the room temp knob high, but not too high in case the thermostat battery dies (contact closed, if thats even feasible) and the stove then attempts to hit the knob value which could result in a toasty warm experience. Haha.

Yep, it's a millivolt thermostat. I used it for years on my Quadra Fire Santa Fe stove. It was extremely accurate and even though it's a cheapie $25 thermostat it works perfect.

I know that many rave about how well the Harman works with the thermistor probe, but mine is way too touchy. If I dial my temp dial back just a little bit, the stove will shut down, and if I dial it up just a little, it's burns like mad for hours on end. It will be great to have an accurate digital thermostat controlling it.

UPDATE: Thanks again for the simple instructions, Ibcynya!

I hooked up my Lux (wired) programmable thermostat last night to my new Harman Advance. This is the same thermostat that I used on my old Quadra Fire stove for years. It works great! The only thing I noticed is that if I have the room temperature dial turned way up on the stove, then the fire is always HUGE, it never throttles down until the set point on the thermostat is reached, which then turns off the stove completely. So I've experimenting turning down the room temperature dial a little bit at a time, just above the 70 degree mark so that the fire will throttle down to a low/medium height.

Very cool to be able to use a digital programmable thermostat - I thought I had lost that feature when I went from the Quadra Fire to the Harman stove.

Good to hear. Yes, you'll want to run the stove with the igniter switch in manual when you are running thermostat priority. And, yes, the stove will run wide open during the call for heat or it will be in maintenance when there is no call for heat. Depending on the swing of you thermostat (mine is 3) and the heat you need, I would suggest you dial back the feed rate to have longer calls for heat vs. having the room temp probe and wall thermostat fighting. When the stove goes into 4 blink mode (thermostat open) it will drop down to maintenance burn until the next call for heat. I've seen no ill effects from this and it keeps the stove up to temp for the next call for heat. When the temp is in the 30's outside, I can go 36 hours on 40 lbs of pellets, so I don't think there is any waste since the house is ALWAYS losing heat anyway.

When the skytech thermostat is calling for heat and the stove is running does the control board see the skytech thermostat setpoint or the control board dial setpoint?

Edit-
In other words, does the skytech just act as an open or close contact or does the control board sense what the thermostat is set to and start to throttle down just before reaching setpoint?

I like your Harman thermostat post. Does does your distribution blower shut off when the stat opens? I have an
Advance that does this and was concerned about the stove overheating as soon as the stat opens and the blower
shuts off. I do think overall the efficiency would be better with a nice hot fire cycling on and off versus running in idle
mode all the time.

I just hooked up my 3301p wireless thermostat tonight. The distribution blower does turn off when the thermostat is satisfied.

I as well hooked up a skytech 5301 last night and my distribution blower shuts off when thermo is satisfied. But it doesnt shut off at that moment its met. It blows a little longer and shuts off. Wish kinda the blower blew in low for a while because there is alot of wasted heat just convecting off of the stove.

Yes you are correct. The distribution blower continues for a little while. I think to cool down the stove slightly to prevent overhearing.

Any ideas?

The control board doesn't even see the t-stat as anything other than a length of wire.

In lbcynya's picture the diagnostic tool is reading the room set point set on the control board.

EDIT: I am wondering what it would look like when the stove is trying to satisfy the skytech thermostat temp.