Harman P43 Remote Thermostat

[Whitenuckler]

I am thinking about upgrading my room thermostat from the stock cable/tip I have stuck in a wall, to the old looking one which is in the center of my basement room where the stove is. There is a cable going from it to my old furnace room. Also, I have a newer one upstairs I could move down. Should I wire the thermostat in series with the existing probe, or is it better to move/extend the probe to a better location without using a thermostat at all? Thanks

 

[bogieb]

It really depends on what your goal is.

I wired my main floor P43 into a thermostat because I wanted to heat the whole floor. I have a 24x40 house where the main floor is very cut up (5 rooms plus bath). All rooms are small, so the room temp probe would shut off the stove before the farther rooms got warm enough. So, I placed a thermostat in my office, which is midway down the length of my house. This has worked out well for me since I have been WFH since 2020 and I can keep my office at a comfortable temp for the 10-12 hours that I am in it. This is also one of the reasons that I use the feed rate to help control the heat - if I had the feed rate at 4, then the living room would overheat before the further rooms got even close to warm.

I wired up the P61a to a thermostat I set up at the opposite corner in the basement - close to, and directly in line with the door to the garage. That is the coolest place, so I control that temp. The pot on the stove had also gotten a flat spot and it was acting weird at my preferred temp. The thermostat takes care of that issue without having to mess with, or replace the board.

I just use cheap, non-programmable Lux thermostats that are battery operated. Not sure I would use that old thermostat, but that's just me.

 

[Whitenuckler]

It really depends on what your goal is.

I wired my main floor P43 into a thermostat because I wanted to heat the whole floor. I have a 24x40 house where the main floor is very cut up (5 rooms plus bath). All rooms are small, so the room temp probe would shut off the stove before the farther rooms got warm enough. So, I placed a thermostat in my office, which is midway down the length of my house. This has worked out well for me since I have been WFH since 2020 and I can keep my office at a comfortable temp for the 10-12 hours that I am in it. This is also one of the reasons that I use the feed rate to help control the heat - if I had the feed rate at 4, then the living room would overheat before the further rooms got even close to warm.

I wired up the P61a to a thermostat I set up at the opposite corner in the basement - close to, and directly in line with the door to the garage. That is the coolest place, so I control that temp. The pot on the stove had also gotten a flat spot and it was acting weird at my preferred temp. The thermostat takes care of that issue without having to mess with, or replace the board.

I just use cheap, non-programmable Lux thermostats that are battery operated. Not sure I would use that old thermostat, but that's just me.

OK, Thanks for the info. My basement rec room where the stove is, is one big room, and the middle of the room is only another 12 feet from where I have the probe stuck in the wall. I have no plan to regulate the heat elsewhere in the house as like yours, mine is closed off.
I do have a circulation blower from my bedroom to behind the stove which gives me a bit of circulation basement/1st Floor.
I could turn it up if I'm not down there, but if I'm there I will need it to be below 24C for sure.

The manual does not mention anything but extending the probe. I believe people have wired the NO contact from a wall thermostat in series with the probe, but get a fault blink due to this. I really have no reason to use an actual thermostat yet as I don't need to have a program right now. I will just add another cable and then hook the probe cable to it.

Also according to the manual the probe should be in the return air path. That is the why they have such a short cable, and most have it on the back lower part of their stove near the room blower. Having it on the wall may not be in the return air flow, but the lower on the wall it is placed the better for that as heat rises.

4 Blinks: Can occur only in Room Temp Mode and
indicates Room Sensing Probe failed or not installed. If a
Room Sensing Probe is then installed, the status light will
automatically reset.

E. Room Sensor Installation
The room sensor is a small temperature sensor on the end of
a 60" wire. This sensor is installed much like a standard wall
thermostat. There is a remote room sensor port on the rear
of the unit for easy external connection. Use standard 18-2
thermostat wire to extend the sensor to the desired location
(50' maximum). The room sensor should be installed in the
location where you want to control the temperature.
NOTE: Distances of more than 25 feet from the unit or in
another room are not recommended. The room sensor is
essential for the P-Series excellent efficiency.
NOTE: It is recommended that the room sensor be installed,
even if only installed on the rear of the unit as a return air
sensor.

 

[Whitenuckler]

Just got finished the work. I found my correct original thermostat cable, and tested it by shorting out the end and reading the other end with an ohmmeter.
I pulled it back from the oil furnace to the wall where the pellet stove is. I cut the probe cable and then used super small wire nuts to make the connections. Just turned the pellet stove on. Works so far, no faults. I will update later today.

 

[Whitenuckler]

Update - works good. I actually should have left the probe coiled up on the back of the stove near the air intake instead of moving it up on to the wall above the stove. The manual says it should be in the air return path. I am in Room Mode,disabled - and the thermostat where the probe is stays at 68F. Above the stove is much warmer, but that's to be expected. It also helps that it's been cool lately, so idle is OK. In this mode, it will shut off the distribution blower as well until it needs it.

 

[bogieb]

I have mine wired in series, and the stoves show a 4-blink fault, but it doesn't mean anything and I ignore it.

My thermostats do not have program capability as I don't need it. They are digital, so probably have a little more exact temp control than the older thermostat. It's also easy to punch a button to change the set temp. When I am in the office, I raise the temp from 68* to 69* because all the electronics tend to keep that room about 1* warmer when I am working. The 'stat also has a 'save" button I can push to just lower the temp by 5* if I wanted, then push it again to raise it 5* (photo from ad below - I don't keep my house that warm)

 

[Whitenuckler]

I have mine wired in series, and the stoves show a 4-blink fault, but it doesn't mean anything and I ignore it.

View attachment 341900

My thermostats do not have program capability as I don't need it. They are digital, so probably have a little more exact temp control than the older thermostat. It's also easy to punch a button to change the set temp. When I am in the office, I raise the temp from 68* to 69* because all the electronics tend to keep that room about 1* warmer when I am working. The 'stat also has a 'save" button I can push to just lower the temp by 5* if I wanted, then push it again to raise it 5* (photo from ad below - I don't keep my house that warm)

View attachment 341901

Yes, I think I had read on here somewhere that that was the only way to do it on a Harman. Some other brands seem to have a couple of stabs with a jumper in between. I decided to move the probe (cut the tip off) as I would need to cut the cable anyway to make the series connection in my furnace room behind the stove. I am happy as it seems to work really well. We had a bit of colder weather, and the regulation was good. Didn't need the room blower at all except at start up. These stoves are great. All the steal heats up and radiates the heat. Not good spot for a cat though.

 

[Whitenuckler]

Gotta love these Harman's. Nice and cosy in the basement. Room Mode, OFF. No room dist fan fan required once the room is up to temperature.