Pelpro PP130 Thermostat Wiring Diagram and Parts List

  • Active since 1995, is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.


New Member
Dec 10, 2022
SW Pennsylvania
First off, I am not encouraging you to do this if you have a perfect stove that does everything you desire. Secondly, I am not trying to take away from a man who is actually selling a system to do this much easier. While I was doing this setup pellet miser was no longer in existence and I did not know that someone else was working on building a product to replace it. I know that now and I believe it is called the Pellet Hoss, and if I can find his website I will link it so if you would rather order one that way. So please, try to refrain from negative comments that take away from the potential help this may provide someone else on the forum. I am totally open for criticism as long as it is meaningful. I am not a professional pellet stove engineer, I work 7 days a week. I did this on my own behalf and for my own testing, it is working very well for me. The wiring diagram is the best I could do with the tools I have to use.

Parts List (I did not research on who has the cheapest prices, this is just for you to see what parts you need.)
1 - 5v relay, Hi/Low Trigger. 5V 1 Ch Relay
1 - Old USB cable or New open ended USB cable. USB CABLE
1 - Millivolt Thermostat (I used a cheapo) Chepo Thermostat
1 - Length of wire needed to run from pellet stove to thermostat mounting location.
2 - Lengths of wire to run from control dial to wherever you are going to mount the relay
You are going to need a way to strip the wire and connect it to the wire coming from the control board to the dial control. I used solder and heat shrink, but feel free to use wire nuts, crimp connectors, butt connectors, whatever way you find suitable. You can let the relay board dangle, but I would recommend mounting it somewhere. Mine is mounted on the back of my stove with velcro.

I will be referencing left and right of the stove as if you are stranding in front looking at the door. Right side is where dial control is located, left side would be where the convection blower is located.

Connecting Stove to Relay
  • Power down stove and allow it to cool down, once both blowers have shut off, unplug the stove.
  • Remove the right side panel to access the wiring harness that goes into the dial control, I just use a 10mm socket and loosen them enough to remove the panel.
  • Locate the main harness plug that goes into the bottom of the dial control, depress the connector latch and remove it from the control.
  • Looking at the connector from left to right, the second wire in should be red, this is the wire we need to splice into.
  • Remove enough of the sheath on the harness to make it easy to to cut the red wire and have enough free end from both sides to work with. (BE CAREFUL YOU DO NOT WANT TO JUST HACK AT THE OUTER COATING WITH A SHARP KNIFE AND POTENTIALLY STRIP THE INTERNAL WIRES CREATING A SHORT) This is fairly easy, but please be mindful when doing it.
  • Snip the red wire. Connect one of your lengths of wire to the red wire coming from the plug, and connect the other length of wire to the red wire coming from the harness.
  • Route you wires to where you will be mounting your relay.
  • Connect the wire from the harness to the COM terminal on the relay.
  • Connect the wire from the plug to the NC terminal on the relay.
Setting up Relay/Powering/Connecting Thermostat
  • Referring to the diagram, there is a blue arrow pointing to the bridge on the relay board. This needs to be set for LOW (They typically ship in the HI position) Just pull straight up on the bridge and move it over one pin.
  • If you are using an old USB cable, cut off the end opposite of the Type A port (We need to retain the end that you would plug into a computer or phone charging brick as this will be plugging into the control board on the pellet stove.
  • Depending on the usb cable you use, it may have 2 wires, or possibly 3 coated and 3 bare. We just need the power and ground. If your usb is backwards from mine, its okay, just swap the wires and try again.
  • Run the RED usb cable to DC - on the relay
  • Run the BLACK usb cable to DC + on the relay. (At this point I would recommend plugging usb cable into the control board on the stove. Ensure the stove is off and you did not leave any wires or tools near the fans or other moving equipment and make sure you do not have any bare connections touching anything. Plug the stove in, if you got the power and ground cables correct on the usb, you should see a green LED light up on the relay if you are using the same one I have, if it does not light up, unplug the stove and swap the two wires.)
  • Connect the WHITE thermostat wire (Red dotted on diagram) to the IN terminal on the relay.
  • Connect the RED thermostat wire to the DC - terminal on the relay. ( I soldered usb red wire and thermostat wire together to make it easier to get in the terminal, not necessary)
  • Run your thermostat wire to the location of where you are mounting your thermostat, connect the RED wire to the R on the thermostat and the WHITE wire to the WH. This is going to vary depending on the type of thermostat you buy, so refer to the manual that is included, but this is the common.
  • Tidy up all your wires, double check connections, mount the relay, check for tools, check wires are not routed against something hot or moving, reinstall the side panel.
Running the Stove via Thermostat
  1. Go through the normal checklist before starting your stove. Exhaust clear, pellets in the hopper, clean fire box and burn pot, no combustibles near by.
  2. Turn your external thermostat to OFF or set the temp well below the current house temp.
  3. Plug in your stove and leave the dial control in off position. After a few seconds the LED on the dial control should be flashing showing it is ready to go. The GREEN LED on the relay should be on showing that you have power to the relay.
  4. Now turn your external thermostat to HEAT or raise the set temp until it calls for heat.
  5. The dial control LED should be blinking rapidly showing that it is priming and starting the on cycle.
  6. The relay should now have a RED LED illuminated in addition to the green one. This shows the thermostat is calling for heat.
  7. The stove will now run on HI until the set temp is reached, at that point it will shutdown as normal.
Quick notes. The stove will run HI/OFF when running. You can also run HI/LO, so instead of going in to shutdown mode when set temp is met, the stove will just drop to the low burn setting. To do this, start with the stove off. Turn you external thermostat OFF or below current temp. Plug the stove in and turn the dial control to low. Allow the stove to come up to temp. Now you can turn your external Tstat to HEAT or set the temp where you want it. When calling for heat, the stove will enter HI burn setting, once temp is met, it will drop back down to low until called upon again. You can also use one of the 1-10 comfort settings, but I have not really found much benefit in it.

I recommend a thermostat with an adjustable swing, differential, whatever you want to call it. This allows you to set how much the temp has to drop below or rise above the set temp before shutting off or starting up. Ex: +/- 3 degree swing set at 70 would drop to 67 and kick on, then rise to 73 before shutting off. This keeps the stove from constantly kicking on and off trying to maintain a 1 degree differential. Placement of the stove and the external thermostat are also going to change this.

If this seems like to much for you to take on, I do believe somebody is currently making a plug and play like pellet miser. I can't find the website and have not used the product myself, so I can not endorse it, but I am sure it works fine and is probably more simple than this.

As previously stated, I did this on my own behalf, for my own stove, in my own house. I am not saying you need, should, or have to do as I did. I am simply putting the information out there and donating my time for someone who may want to do the same, or just understand how it can be done.

Pelpro PP130 Thermostat Wiring Diagram and Parts List
  • Like
Reactions: Jeremy6500 and _56
I appreciate the write up. Always great to have options.

Good thoughts on the thermostat swing setting. One of my worries about using a room thermostat was the constant cycling during the times of the year when the stove returning to low when heat isn’t calling would still be too much.

I don’t believe person making the Pellet Hoss has a website. They have a Pellet Hoss page on Facebook and you can message then if you want one. I haven’t hooked mine up yet, but the persons service was excellent and the product looks professional.
Well that makes sense why I couldn't find the website! Yes the constant cycling would potentially be hard on the igniter, especially if the stove burning on low is too much sometimes.

Another, simpler way to get more consistent temperatures is to extend the ambient probe. This is what I did while I was building everything for the external thermostat. Just simply added in about 20' of wire to lengthen the probe and ran it upstairs. Just with that, it kept my main floor quite steady at 70-72 on setting 1-2 without huge swings or short cycles.
  • Like
Reactions: Jeremy6500
My probe does an okay job, but not great. The previous owners installed the stove in a bad spot for drafts and right in front of a window, so no good way to route the probe to a different location.

I will be moving the stove to a different location in the house and when I do I will be able to run the thermostat wire through the wall for a cleaner looking install.

Nice thing is that adding the thermostat doesn’t disable the dial/temp probe (or at least I don’t think it does). Gives me the flexibility to do either.
You are correct as far as I can tell with my setup. I can set it to low/1-10/hi or off as normal. The thermostat is just in addition to the dial instead of replacing. So say your set on 3 and it's burning easy, but your wife burns the roast and has to open a window on the main floor where your external thermostat is, it will call for heat which will kick the stove into high until the temp is met. At that point it will either go back to mainting comfort level 3, or shut down because the ambient probe is warmer than level 3. After that it will continue to operate as normal.
  • Like
Reactions: Jeremy6500