PB105 seems to hang at 190°

[scooter]

My PB105 was just installed. Setting: 180°Max and 150°Min. No Out side temp sensor. Feeder set at 3.

On the first day of operation it seems to run up to 190° and stay there with a strong flame. I expected to go through between 1 and 2 bags of pellets max in a 24 hour period. I went through about 2 1/2 bags in 20 hours and expect to hit close to 3 bags by the 24th hour. The temperature overnight was about 0°, during the day today was between 15° and 20°. My house is 1700sq ft. with 2 heat zones and a hot water coil. Thermostats set at 68° and 67°. I monitored the boiler and recorded the values, see below.
Can you tell me if this is the normal operation. (I don't think so!!) I thought if the setting were at 180° max and 150° Min the flame would go out at 180° and come back on at 150°

Harmon PB105 Boiler
Settings:
• Max temp setting 180, Min temp setting 150°
• No out-door temp sensor connected.
• 200 lbs pellets loaded
• Feed setting 3

12.22.08 “First fire” 10pm, O/S Temp -4°
Ran up to 180° and started to shut down as it approached 180°. Everything seemed to run fine.

12.23.08, 6am: 8 hours of run time. O/S Temp -4°
I did not note the boiler temperature. Just-under 1 bag of pellets used

12.23.08, 6pm: 20 hours of run time. O/S Temp Low -4° High 15°

• 6pm Boiler temp 190, Small flame, Feeder running, total pellets used: 2 ¼ bags used / Turned all heat zones circulators off.
• 6:20pm: Boiler temp 190, Small flame, Feeder running
• 6:40pm: Boiler temp 190, Small flame, Feeder running
• Adjusted Max Temp from 180° down to 170°
• 6:55pm Boiler temp 190, No Flame, Feeder not running.
• 7:15pm Boiler temp 160°, No Flame, Feeder not running.
• Changed boiler setting to Max temp 177°
• 7:40pm Boiler temp 190°, Strong flame, Feeder running
• 7:55pm Boiler temp 190°, Strong flame, Feeder running
• 8:15pm Boiler temp 190°, Strong flame, Feeder running
• Changed boiler setting to Max temp 170°, Flame was out in 10 minutes. Boiler temp 190, Flame, Feeder not running. Boiler temp was dropping due to circulators turned back on
• 8:40 Boiler was running again, Boiler temp 160°, Strong flame, Feeder running
• 9:34pm Boiler temp 175°, Strong flame, Feeder running, I started getting a flutter from the air slot cut into the door. It would come and go.

 

[AndrewChurchill]

The PB will stop feeding pellets when it hits the max temp but there is still a lot of residual heat in the remaining pellets. Also, the temp gauge that come with the PBs are notoriously inaccurate so it's possible your gauge is 10 degrees off.

If you are NOT using the outdoor air sensor then the minimum temp knob simply becomes the on/off switch. The boiler is going to maintain the max temp setting at all times. The only time the min temp knob is used is when the outdoor air sensor is connected to the PB.

 

[scooter]

Thanks, that explains why it was running so high annd went through so many pellets. The outside sensor will be hooked up today. You were a big help Thanks