Sensor wire on a P-43

[referee38]

How long can you make the sensor wire and what kind of wire do you use. The one that came with the stove is only about 4 feet long.

Thanks,
Ed

 

[silverfox103]

Harmon recommends not extending more than 25 feet. I think they recommend 24/2 wire. The 4 ft sensor wire, needs to be on the very end.

Tom C.

 

[76brian]

what kind of wire do you use

Any kind of 2 conductor copper wire will work. I hooked mine up last night, I just used a 30' chunk of cat5e networking cable because that's what I had on hand (only used two of the pairs). Some sort of speaker wire would work perfect also. Doesn't need to be heavy gauge, there's only a minuscule amount of current there.

 

[referee38]

Ok, so I just wire the sensor that's on the stove now to the end of the 2 conductor wire that I add?

Ed

 

[76brian]

Yup, exactly. Polarity doesn't matter either so don't worry about that.

 

[silverfox103]

Although I'm sure Brian meant well, cat5e cable is not made to be used for wiring a thermostat. Thermostat wire is meant to be used for wiring thermostats, plain and simple! The manufacturer recommends 24/2. That's what the wire on the sensor is. Sorry, you don't just use what you have on hand as he did. At HD I bought 50' of thermostat wire for $10. It's pretty inexpensive to do it correctly.

Tom C.
Licensed Master Electrician since 1975


This is from Harman

Technical
Bulletin
MODEL
Pellet
3/26/2007
Adding a programmable set back thermostat for all Harman Pellet Stoves
Thermostat must be:
1) Millivolt compatible
2) Gold Contacts
3) Low Voltage
4) Low current
Recommended Honeywell Thermostats.
RTH230B
RTH6300B
These thermostats are available at hardware stores and home improvement retailers.
Note: If there is a jumper between Rh and Rc it must be removed from the thermostat�s terminal block. Use
minimum 2- conductor 24 gauge twisted pair wire to connect the thermostat.
Connect the thermostat in series with the room sensing probe using the Rh and W terminals on the
thermostat. (See Fig. 1) The set back thermostat must be used in conjunction with the room sensing probe
(except the P38).
Thermostat Settings:
Occupied Mode:
In occupied mode program the thermostat to its maximum temperature setting. (i.e. 82 Deg. F) The stove�s
room sensing probe will control the room temperature. Set the stove�s temperature dial to the desired room
temperature. (i.e. 72 Deg. F)
Unoccupied mode:
In unoccupied mode program the thermostat to the desired set back temperature. (i.e. 60 Deg. F) When the
thermostat opens (is satisfied) the stove will go into a 4-blink status. If the stove is an auto ignite stove and
the auto-manual switch is in auto mode the stove will shut down. When the thermostat closes (calls for heat)
the 4-blink status will automatically reset and the stove will ignite.
If the stove is a manual ignite stove or an auto ignite stove with the auto-manual switch in manual mode, the
stove will go into a 4-blink status when the thermostat opens (is satisfied) and the stove will go to a
minimum burn and stay there until the thermostat closes (calls for heat). When the thermostat closes (calls
for heat) the 4-blink status will reset automatically.
Note: A 4-Blink status is described in the owner�s manual. The status light on the stove will blink 4 times,
pause, and blink 4 times continually. This error code is the board recognizing that the room sensing probe is
not connected or has failed. Breaking one leg of the room sensing probe wiring with the thermostat, as we
are doing here, causes the 4-blink status. This error automatically resets when the board recognizes the room
sensing probe has been reconnected.

 

[76brian]

Copper wire is copper wire. I didn't tell him to use cat5e, I just told him that's what I used. The bulletin you posted says 2 conductor twisted pair, 24 gauge... well guess what? That's exactly what cat5 is. You just don't need all the pairs.

He also didn't ask about hooking up a thermostat, just extending the length of the wire on the temperature probe.

As long as the connections are solid (I crimped on spade connectors, and used heatshrink around them), the stove or the temp sensor doesn't give a rats ass what kind of wire it is.

I guess I won't tell you that one of my radio towers uses thermostat wire for the rotator controller either But it's not rotator control wire OH NOES :ahhh: