PF100 Normal Operation Question

[Corksterman]

I had a Harman PF100 installed at the end of last year's heating season (April). I only burned 10 bags to make sure the thing was operational. I used the wood stove I have to heat the rest of the season.

Now that this heating season has come I am using the pellet furnace full time. When the temperatures outside were 50+ the pellet furnace would turn on raise the temperature to the desired level and then go through its shutdown phase. It would ultimately shutoff until the the temperature in the house was a couple degrees below the temp set on the wall control.

Now that the temperatures are in the 30's or lower, the pellet furnace will turn on and raise the temperature of the house to the desired setting, lets say 70 degrees. Then the temperature of the air coming from the duct work lowers but the pellet furnace continues to run forever keeping the house at a consistent temperature at 70. It will continue running until I let the hopper run out of pellets.

Is this the normal operation of the pellet furnace or should it complete shutoff from time to time during the day?

Additional information:
Location: Northern New York
House: 2 stories ~1700 sq ft plus a full basement (which is where the furnace is located)
Feed rate: 4
Normal Setting and Auto Ignite
Exhausted horizontally about a total of 5 feet.
Pellets currently being used: Curran Premium Hardwood-Softwood Blend

Thanks.

 

[Delta-T]

you may need to adjust the temp differential in the plenum sensor. if the house cools off during the shutdown cycle because the air coming out of the vents gets cooler, it may be telling the machine to turn back on before it can get to shut down. the ESP probe tells the unit when its internal temp is low enough to shut down, so you may want to take a look at it to make sure its not covered with ash or something, can be tricking it into running as well.

 

[Corksterman]

Thanks for the tips. I wouldn't have thought of the temp differential. I'm going to adjust it and see if that works tonight. If not, I'll check the ESP probe.

Thanks again.

 

[mcmaxx]

The pf100 will shutdown if in autolite and automatic, if the demand for heat is no longer needed and the house can maintain proper temps for a period of time it will shutdown. Not sure how long it needs to maintain temps before shutdown begins though?

 

[Corksterman]

Just for future reference of other people. The installer set the limit switch to 80 and 110. The manual recommends 120 and 150. Those were obviously too low and would cycle on the furnace as it blew cooler air into the house. I changed them to 110 and 150 so the fan wouldn't cycle on as much when shutting down. I thought it was working but my furnace was burning through 3 bags a day... which from what I hear is way too much... and that would cost me more than my fuel oil furnace to heat this house.

So I ultimately went out and bought a lux digital thermostat that would allow me to set a "swing" value of 2.25 degrees. Basically what the TS that came with the machine does. So, it shuts off now and turns one when needed. I'm burning about a bag and a half a day now... which I assume is more on average.

I am going to call a local guy that does spray foaming in basements. I'm hoping that will help keep some heat in as well.