Alternative to Room Temp Sensor?

  • Active since 1995, Hearth.com 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.

kilogulf59

Member
Dec 17, 2017
45
Juneau County WI
I have a Harman P43 and was wondering if there was an alternative to that ridiculous room temperature sensor, which, by the way, I am on my second one in five years? I Harman makes one, nonetheless it's expensive and Sky something-or-another makes some but which model? There's some threads here however I am looking for current information, these threads are several years old. It need not be fancy, programmable model, I just was something akin to a simple wall mount thermostat.

What do you folks use?
 
Not familiar with the "Harmon" setup.

On my Enviro I use a LUX TS500U regular 2 wire thermostat. Think it was about $30.00 bucks 5 years ago.

Is there a thermostat connection on the Harmons? might be a cheaper alternative.

---Nailer---
 
There's a two prong receptacle in the back for this ungainly PIA thing they call the room temperature sensor. I have mine tied to a 5-foot step ladder as far from the stove as it will reach. Finally, it is working somewhat properly, i.e. according to it's settings. The setup looks completely Rube Goldberg...I can't imagine having that in our living-room...

This is my first pellet stove and I was told Harman was a very good brand, that notwithstanding, I find the controls to be overly sensitive at times, that ESP needs to be cleaned, at least, every ton or so, to get the stove to function as set, and every year there seems to be something that needs replacing. I like the idea of a pellet stove but would do much more research should I ever purchase another. It seems to me that they have a good idea but, perhaps, need to work out the kinks and that POS temp sensor has to go. For the price, I'm not impressed.
 
The only time I've had a room sensor fail was when the connector pulled off, ey typically last a long time.

Sounds like you would be best to use a programmable mili-volt thermostat inline with room probe which offers good control of temperature without fiddling with control board knobs. No wires have to be cut, just a few crimp on connectors to make this work. Set control board at higher room temp than needed (Like 80F), then use thermostat to regulate it while running in ROOM Mode. Works great.
 
My room temp sensor is 10 years old and trouble free.
 
The only time I've had a room sensor fail was when the connector pulled off, ey typically last a long time.

Sounds like you would be best to use a programmable mili-volt thermostat inline with room probe which offers good control of temperature without fiddling with control board knobs. No wires have to be cut, just a few crimp on connectors to make this work. Set control board at higher room temp than needed (Like 80F), then use thermostat to regulate it while running in ROOM Mode. Works great.

Sounds like that what I'm a lookin' for. Any brand/model recommendations?

My room temp sensor is 10 years old and trouble free.

Mine did...from the manual: "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.

NOTE: Unit will not start in "AUTO" with this status error."

Had to run it on stove temp until the new probe got here. How do you have your probe set up?
 
Here’s a couple of pics of mine. You could always go wireless if you want to. Install your tstat where you want it. Run the wire to the back of the stove and plug one of the wires into the stove. Plug one of the probe wires into the stove. That will leave you with a probe wire and tstat wire that need to be connected together
 

Attachments

  • F45A102B-D809-4CAC-8D93-FEA7DBAF1EB0.jpeg
    F45A102B-D809-4CAC-8D93-FEA7DBAF1EB0.jpeg
    101.8 KB · Views: 551
  • 4E6F3CE7-1E62-4898-8BC3-493A56D5A34C.jpeg
    4E6F3CE7-1E62-4898-8BC3-493A56D5A34C.jpeg
    68 KB · Views: 524
  • Like
Reactions: THE ROOSTER
I'm using a digital (but non-programmable) Lux thermostat set up in a room halfway down the house from where the stove sits. I'm running the thermostat in parallel so if I want I can change the mode - it only controls the stove when in room temp.

Thermostat wired to P43-close.jpg
 
There's a two prong receptacle in the back for this ungainly PIA thing they call the room temperature sensor. I have mine tied to a 5-foot step ladder as far from the stove as it will reach. Finally, it is working somewhat properly, i.e. according to it's settings. The setup looks completely Rube Goldberg...I can't imagine having that in our living-room...

This is my first pellet stove and I was told Harman was a very good brand, that notwithstanding, I find the controls to be overly sensitive at times, that ESP needs to be cleaned, at least, every ton or so, to get the stove to function as set, and every year there seems to be something that needs replacing. I like the idea of a pellet stove but would do much more research should I ever purchase another. It seems to me that they have a good idea but, perhaps, need to work out the kinks and that POS temp sensor has to go. For the price, I'm not impressed.

I've never cleaned the ESP to either stove. When I clean out the exhaust it does get brushed, but no actual special cleaning. I use a thermostat on the P43 because I want more fine control. The P61a doesn't need to be exact, so I just let it run off the temp probe.

Cleaning for these stoves is much less than other stoves I've had (US Stove and St. Croix). and the only things I've replaced are door gaskets. Sorry you find the stove too difficult to maintain.
 
Here’s a couple of pics of mine. You could always go wireless if you want to. Install your tstat where you want it. Run the wire to the back of the stove and plug one of the wires into the stove. Plug one of the probe wires into the stove. That will leave you with a probe wire and tstat wire that need to be connected together

You have yours set up the same as mine (except for type of thermostat).
 
Thanks for all the input folks.

I think I'd like to connect a wireless thermostat to it, a regular one, i.e. non-programmable. Now would this be just any thermostat or are there ones specific to this application? Remember, I'm new to this pellet stove thing and electronics are not my forte.

Regarding the stove maintenance, maybe it's a combination of a little bad luck (which is the norm for me) and the pellets used. There's not a lot of choices out here and we burn about four to five tons per year depending on the weather. The stove works, it's downstairs and heats the entire house.
 
  • Like
Reactions: bogieb
A few of us Harman guys in the forum just coil the room probe up and tape it to the back of the hopper, let the probe end stick out to the side about 3 inches and ab out 3 ft off the floor.. Guys people have a differential between the stove temp and house thermostat but it's consistent. Mine and some others in the forum are dead on. my room probe is out of harms way and accurate when mounted this way. It's the same age as the stove.
 
Here’s a couple of pics of mine. You could always go wireless if you want to. Install your tstat where you want it. Run the wire to the back of the stove and plug one of the wires into the stove. Plug one of the probe wires into the stove. That will leave you with a probe wire and tstat wire that need to be connected together

So your Tstat is a 2 wire? You plug the black wire from Harman's probe into stove, red from probe into white of Tstat & then red wire from Tstat into stove? Am I seeing your picture correctly???
 
Yes sir. Works like a champ
 
  • Like
Reactions: THE ROOSTER
I've never cleaned the ESP to either stove. When I clean out the exhaust it does get brushed, but no actual special cleaning. I use a thermostat on the P43 because I want more fine control. The P61a doesn't need to be exact, so I just let it run off the temp probe.

Cleaning for these stoves is much less than other stoves I've had (US Stove and St. Croix). and the only things I've replaced are door gaskets. Sorry you find the stove too difficult to maintain.
i have a long botte washing brush.. bristtle type.
i brush the esp once in a blue moon....nothing much lives on the probe except dust.
 
I also run a digital thermostat wired in series with the probe as shown in the stick thread. I set the Harman temp to 80 degrees and run the digital sat in programmable mode or manual mode. The stat will keep the temperature with 2 degrees of the set point. The system has worked flawlessly for 5 years. My stat is a Hunter Programmable I bought for 20 bucks. The thermostat you use must be millivolt compatible or it won't work.
Ron
 
I also run a digital thermostat wired in series with the probe as shown in the stick thread. I set the Harman temp to 80 degrees and run the digital sat in programmable mode or manual mode. The stat will keep the temperature with 2 degrees of the set point. The system has worked flawlessly for 5 years. My stat is a Hunter Programmable I bought for 20 bucks. The thermostat you use must be millivolt compatible or it won't work.
Ron

Oh yeah, that is important piece of information - set the stove temp way above what the thermostat will be set for.

IIRC, it doesn't matter which wire from the thermostat is attached to the probe versus into the stove.

Thanks for all the input folks.

I think I'd like to connect a wireless thermostat to it, a regular one, i.e. non-programmable. Now would this be just any thermostat or are there ones specific to this application? Remember, I'm new to this pellet stove thing and electronics are not my forte.

Regarding the stove maintenance, maybe it's a combination of a little bad luck (which is the norm for me) and the pellets used. There's not a lot of choices out here and we burn about four to five tons per year depending on the weather. The stove works, it's downstairs and heats the entire house.

I don't mess with electronics, but this was very easy for me to do myself. I believe you want a thermostat that will work with millivolt. This is the one I have, but it is not wireless. Look for something that is designed to work with gas millivolt heaters and you should be good.

millivolt thermostat.JPG
 
  • Like
Reactions: THE ROOSTER
I also run a digital thermostat wired in series with the probe as shown in the stick thread. I set the Harman temp to 80 degrees and run the digital sat in programmable mode or manual mode. The stat will keep the temperature with 2 degrees of the set point. The system has worked flawlessly for 5 years. My stat is a Hunter Programmable I bought for 20 bucks. The thermostat you use must be millivolt compatible or it won't work.
Ron
That's the way mine is setup.. Works great!!!
 
Skytech 3301P is what you want. I have one hooked up to my Harman P68 and it works great. Couple of easy connections and set it to the temps you want the room to be. Or program it to come on and shut off when you want.
 
First off, thanks you everyone, you've been more helpful than you know...

A few of us Harman guys in the forum just coil the room probe up and tape it to the back of the hopper, let the probe end stick out to the side about 3 inches and ab out 3 ft off the floor.. Guys people have a differential between the stove temp and house thermostat but it's consistent. Mine and some others in the forum are dead on. my room probe is out of harms way and accurate when mounted this way. It's the same age as the stove.
This is looking more attractive all the time, especially based upon my needs.

i have a long botte washing brush.. bristtle type.
i brush the esp once in a blue moon....nothing much lives on the probe except dust.
That's a darn good idea, I'm going to get one.

With regards to the thermostat, I am seeing great variances in price. Some are below $20 and others, like the Skytech 3301P, which looks like a VERY nice unit, it over $200.

One thing is for sure, I don't want to have to run wires, so the unit's got to be wireless and programmable isn't a necessity as I don't mess with it. The stove is set now to keep the downstairs at 70° to 72°. This keeps the upstairs at 66° roughly, depending on the outside temperature. Basically, the stove never shuts off once it's below 30° outside. This setup works pretty well until the single digits set in, like the past several weeks, then the furnace may kick in once in a while to keep the main floor above 64°.

Now that I think about it, that stove is doing a pretty damn good job as I'm in central Wisconsin and have a decent size home.
 
  • Like
Reactions: bogieb and Tonyray
This is looking more attractive all the time, especially based upon my needs.

Well you have nothing to lose but a piece of duct tape or other attaching medium. I have mine so it keeps the house about 1 degree off from the house thermostat, if I set the stove at 75, the house ( downstairs ) reads 74ish, for instance. The good news is that is 24/7, it varies very little, though pellet consumption varies according to the weather and when we get into single digits i then switch the stove over to Stove Temp mode, turn it down a little bit and the house thermostat up, letting the heat cycle on periodically vs burning the extra bag of pellets the stove would consume in that weather and colder.

I have the probe sticking out the left side of the stove and I imagine if I moved the probe down nearer the floor by a foot or so I could dial out that 1 degree difference. It's just that it has a convenient home where it is, been there for two years now. It spent a year or two on the other side but it was catching a draft over there in 40mph winds, which I have since found the source of ( fireplace molding was leaking in those kinds of winds from the NW).
 
  • Like
Reactions: bogieb
I will give it a try.

Why do you switch to stove temp?

We were exceptionally warm here last night and I packed the hopper full and checked it this morning, about 12-hours later, and it barely used half the hopper. When it's single-digits or below out the hopper would've been just about empty. FYI, we burn Henry County Wood Pellets, they're what's available around here.
 
Why do you switch to stove temp?
It's not good to put two automated feedback loops in parallel which is what two room temperature systems would create (the temperature sensor controls the amount of heat from the system). The main furnace is on one (its thermostat), and a pellet stove on room temperature is a second. Because they take differing times to ramp up heat output, you'll get large temperature swings if the thermostats are near each other. Usually a central heating system is faster, and when the room reaches your desired temperature, the pellet stove is still ramping up and putting out a lot of heat - creating the overshoot.

The farther apart the temperature sensors the less impact there is overall - like having two zones.

Putting the stove in stove temperature mode is essentially one constant output, and the only automated feedback loop is the furnace. The stove creates a base level of heating, and the furnace adds the additional heat as needed.
 
  • Like
Reactions: alternativeheat
I will give it a try.

Why do you switch to stove temp?

We were exceptionally warm here last night and I packed the hopper full and checked it this morning, about 12-hours later, and it barely used half the hopper. When it's single-digits or below out the hopper would've been just about empty. FYI, we burn Henry County Wood Pellets, they're what's available around here.
Why ? Much as jp99 stated,except in my particular application the reverse happens. IE: if I want the house heat to cycle I have to turn down the temp on the pellet stove or the house heat will never come on but gobble pellets. Yet once I turn down the pellet stove then the house heat takes over after the first cycle or so. So I set a known fixed setting at the stove in single digit or colder weather of Stove Temp Auto and around heat level 4ish and set the house heat to what I want the house to be, then in due time the house thermostat will call for heat and the stove will hold that temp for hours (after the heat turns back off) before it calls for heat again. I let the house thermostat do the work of determining house temp, usually 73 deg daytime and 71 at night. Then when it goes back into upper teens and above outdoors, I switch back to room temp mode and 73 or 74 deg at the stove and the heat at 70 or 71 but the heat will never come on because the stove is overriding it.

My purpose is even heat at a two bags max per day mid winter burn rate, right now I'm burning 1-2/3 a day in room temp mode with nights in the mid 20's,days in low to mid 30's. But the house is 74 degrees. I can ride my exercise bike in my studio in my short jammy bottoms ( or less if I wanted to) LOL.
 
  • Like
Reactions: jp99
OK, gotchya guys.

The way I'm workin' it is the stove, downstairs, is set to about 70° room temp and the furnace thermostat, upstairs, is set to 64°. The stove will keep the upstairs between 65° and 68° depending on outside temp. When it drops to single digits or lower, the coldest it will get upstairs is 64° then the heat kicks in. When it's real cold, I usually manually kick the furnace up to 66° in the morning to take the chill off the house before the wife wakes up. Then I put it back down again.

FYI, my burn rate is about one to two bags a day throughout the winter depending on the outside temps. That equates to approximately four tons per year. I've found it's not worth running the stove in early fall or late spring. I run the furnace once in the morning to take the chill out.