Purchasing Harman P38+ / Questions?

Hello, Michael from Fairbanks, Alaska here. (Yay -40 winters)
New user to forums here, been lurking for a bit as I learned about pellet stoves. I have researched and decided upon purchasing the Harman P38+. There were a couple issues I had questions about, so here I am!
1) I saw a thread in regards to using setback thermostats with pellet stoves, and was curious if anyone knew what specific thermostat I needed to put inline with the room sensor for the P38+. I saw one thread, but it it was not specific enough for my tastes.
2) Anyone have experience with using combustion air @ -40 degrees? My boiler has a nice long duct, but in this situation the duct will only be a foot long, and likely freeze up with condensate, I am thinking. ((The boiler duct freezes about a foot out from the wall)) The local dealer said he has never installed combustion air, and would not recommend it. I would like to avoid negative pressurizing my house, but it doesn’t seem like I have choice when the air is that cold.
3) Is the only difference between this and the P43 the automatic igniter / off /on features, and the fact that the P43 comes with a room sensor?
Thanks for any help you can provide, it is appreciated.
-Michael

Welcome aboard Michael. The Harman pros will be along shortly.

Congrats on your stove purchase (good choice ) and welcome. You may want to look into Selkirk DT venting. The outside air coming into the stove is preheated by the exhaust air going out of the stove. Works nicely for me and a few others. Funny thing is that the installer told me that this wouldn't happen. All I know is that where my venting goes through the exterior wall the outside is COLD to the touch (roughly the same temp as outside). And the venting piece where the outside air seperates from the concentric venting is very hot to the touch. I haven't taken temperatures yet but am hoping to this winter.

Excellent advice. I use it on two applications, couldn't be happier.

as a short answer, I'd follow what the local dealer says....Ive no experience in running a stove at -40 degrees, and cant really comment on plugging of the intake with frozen condensation, but I can see it might happen.....isnt the air fairly dry though at -40?

here is the manual, if it helps:
http://hearthnhome.com/downloads/installManuals/PP38.pdf

as for a setback thermostat and precise instruction, I need to check service bulletins, which I cant from my current locale.

this model is close to the p43....different curcuitbord, of course, as the p38 doesnt autoignite. You can add the room sension probe for very little money too....the new p38 board is the same as the old p61 board......

Welcome Michael. My thoughts are the colder the air the more O2 it holds per cubic foot. The more O2 the more fuel you can add and still get a clean burn. I would insulate the intake air duct to help with condensation on the outside of the pipe and not worry about the inside freezing up, very little moisture in -40 air. Just my 2 cents.

My P38 also has a short OAK (14"). Although we don't hit -40 here we have hit -10 to -15 several times. At one time I insulated the air duct and after a while (at below 0 temps) the stove shut down. Not sure why. I removed the (frozen) insulation and pointed a small floor heater at the duct for about 10 minutes. I was able to start the stove and it worked fine w/o the insulation. Yup there was a lot of frost / ice on the duct so I kept a small folded towel underneath the pipe to catch the drips when it finally thawed. Bottom line is dealing with -40 I would really consider the Selkirk.

Welcome to the Forums....

Harman is a great choice and there is no replacement for displacement. Auto lite is a nice feature. But wouldnt be a deal breaker.

My deal breaker is being cold. If the budget allows, I would go bigger (P-43 is still about the same, but P-61/P-68 now thats some serious HP ).

I really do appreciate the warm welcome. R-19 walls, R50 ceiling, 2-story. Noone sells Selkirk up here, so if I want it, I'll have to look and see what kits they make for ordering.

So the stove itself is 2,700. The P61 would be 4200. Include around 500$ to install it myself. 3,200 or 4,700. I just don't have money for the P61, and if I move in 3-5 years it wont pay for itself.

I am pretty mechanically inclinded, but did not see any ratings for the thermostat / sensor / wiring.

The home is half a duplex. 1650 SQ FT living space. I went through 1k gallons of heating fuel last year.
However, the garage is a radiant heat slab, and keeps the room above it warm.
The boiler room is under the other bed room, and keeps that room warm.
So the goal of the pellet stove is to heat the sunken living room (12 foot ceiling), the master above it, and the dining/kitchen area. I attached a image.

Kitchen/dining 30x12
Living room 16x20 with ceiling Master is directly above it, with ceiling fans.
So around 1.2k SQ FT.

The house had a energy audit and loses about 57k BTU per hour, but that includes the garage. The boiler is 64k BTU, system is glycoled, and runs 40+ minutes out of the hour when it is -40 (Perfectly sized)
Ideally I don't expect the zones in the living room/upstairs (Thermostat is at top of stairs) to ever kick on with the P38, and I would be happy with that. I don't expect the artic entry (Kept @ 40) and the garage to get much help from the stove.

When you get thermostat answer I would appreciate! I googled the crud out of that one.

Thanks again everyone.

Hello

Check out the Lux LTX1500U T-Stat at Lowes. It has a swing setting that most pellet stoves require. It can be used manually or as a programmable set back thermostat. If any T-Stat can be used I would say this one will work!

If you get the optional probe the T-Stat goes on one leg.

http://www.lowes.com/pd_24971-37422-LTX1500U-006_0__?productId=3382134&Ntt=lux thermostat&pl=1&currentURL=&facetInfo=

See specs
Use with Pellet Stove for mV Thermostats - Yes

See TX1500U manual on Lux Web Site
http://www.luxproducts.com/support/TX1500U_ENG_WebManual.pdf

Moe:

I do recall a thermostat for the "old" P38's prior to the cucuitboard changeout of 2012....I dont think it was a "setback" unit, but the part number is 3-20-12080.....I have a feeling with the advent of using a room sensing probe, the old thermostat might not be compatible, BUT others here have used setbacks on p61a's, etc.....so, given the possiblilty that the p38 now can utilize the room sensing probe that the P61a's use, there is a possibility that a setback might work.....here is the instructions for THAT setup....hope it helps! Its pretty old, dating back to 2007, but now with the new curcuitboard...just maybe......

Hello

From your bulliten

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).

What about the P38?

I own a P38 and a P68. The P68 you can use a setback thermostat, the P38 you cannot use a setback thermostat. You have to use a mechanical thermostat, available at Lowe's or HD. The cost around $15. Digital thermostats will not work (unless the 2012 P38 is different than all the other years). The dealer also has them, they probably get around for the same thing. Have them throw in a thermostat with the deal.

By the way the P38 is a great stove and works well with the thermostat. It is also very easy to start, buy yourself one of those small propane torches. You do not need any gel.

Good Luck

Tom C.

the "newest" P38's have the same curcuitboards as the old P61's......therefore, using the bulletin, its still valid. If he has an "old" p38, there are still thermostat leads on the board, but I dont think the bulletin covers that.....had to assume the new unit the OP is buying is, in fact, a new unit.

Tom: Harman did make a thermostat for the "old" P38......part # 3-20-12080. But, like you alluded to above, the P38 has changed to another curcuitboard....it IS different than other years......now has a feed rae knob, a temp knob, and a room temp/stove temp knob.

http://hearthnhome.com/downloads/installManuals/PP38.pdf

My P38 is old, probably 12 to 15 years old. I love it! So, with the new board and you can use a programmable thermostat, that makes it even better.

I've told this story before, but here goes again. A good friend of mine was out of town working. He came home and his wife surprised him with a new P38 in his living room. For whatever reason, he never liked it, not sure if it was the cleaning, pellets, etc. Unfortunately, his wife died from cancer. She wasn't gone 2 weeks, and he had the stove taken out of the house and put in the garage. Several months went by and he called me to ask what it was worth, he said it was old but ran good. I told him I didn't really know. He knew I had the P68 and he really loved the automatic light. I told him the manual light might be a drawback. He said he was going to ask $500. I told him I would be interested if it had automatic ignition, I was close to buying a second stove the P43.

I thought about it for a month or two, I figured I'll try it and if I don't like it, I'll just sell it. I called my friend and told him I'll take it. He said I'll throw in a generator------great!

Anyways, couldn't be more happy with the P38.

Tom C.

the fact aht it doesnt autignite isnt really a drawback.......one thing less that needs service! My P61 doesnt autoignite either, and I dont feel particularly disadvantaged because f the fact it doesnt autoignite....enjoy it!

So did some more homework. Found a better dealer with better prices.

90% going with a P68 (For the price I wouldve been paying for a P43...)

As other users stated P38 probably not enough to heat the place, and even the P68 probably won't be able to heat the upstairs, from all the threads I have read about heating the upstairs.

Depends on numerous things. House layout, insulation & infiltration are the big ones. I have 2250sf and can heat the entire house with a P61A. Upstairs (bedrooms) are not as warm as downstairs but we like it cooler in the bedrooms anyway.

I am from MN and I get close to -30 but rarely. See if dealer can give you name or two of local customers to see about thier setups and troubles with cold air. I find it hard to beleive that your home has less insulation than here. To bad could not ship you a used stove as there is some nice harmans on CL for 1000 or less. I am going to try a crosslink boiler loop in a PC45 to heat 1500 ft of basement and the air side to heat 1500 ft of upstairs. Don't like paying for Arab social programs.

I love thread like this - Good lucky MightyMoe - I can't wait to hear what you eventually go with. If you can snap a picture when it's all said and done !!

-Mike
(another p38 owner)

Average winter temperature 2009: -.6 degrees
Coldest day: -41.1 degrees, January 12
Warmest day: 48.2 degrees, March 29
Days with snow: 38%

Last January I don't think it ever got above 0, and stayed -20 most the month. Went through about 900 gallons of fuel.

I don`t mind the P-38 manual light . It takes only 30 seconds or less to mix a cup of pellets with a little gel , or even better a couple oz of 91% alcohol ($2.49 qt in Wal mart). Then dump it in the burnpot and light it up and you have an instant fire in a lot less time than auto light and no worries about the ignitor ever burning out .