Harman Pb105 Which setting would use least pellets

Lower your minimum setpoint. If most of your use is for hot water, the mixing valve will compensate for lower temperatures. A wider spread will require less frequent cycles.

When I had my PB105 I set the upper limit to 180 and the minimum to 140. I also had the outdoor air temp probe installed and I let that automatically adjust the upper limit based on the outdoor air temp.

As for the feed rate I set that by putting my boiler under a heavy load by filling up my tubs with hot water. I then set the feed rate to 6 and watched the burn pot. If I saw unburned pellets falling into the ash pan I backed off the feed rate a little bit and then watched again. I left the feed rate alone once I had about an inch of ash forming between the burning pellets and the edge of the burn pot.

The only time I adjusted the feed rate after that was if I switched the brand of pellets. Most of the time my feed rate stayed between 5 and 5 1/2 in the 5 years I used the boiler.

Once you get the feed rate adjusted leave it alone and let the onboard electronics do the work for you. In my experience they did a great job.

When I'm using it just for hot water, I set the temperature range about the same as you have it and I leave the feed rate between 4 and 5, maybe closer to 5. My goal was to keep a wide enough range so it cycles less and keep the water temperature on the lower end of the scale.

Chris04626 said:

I tried putting it on 140 and 175 and plugged in the outside sensor and i burned 1 bag in a day for just hot water. Not bad

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So, if you use $4 per bag ($200 per ton), you would be spending around $120 per month to heat your hot water.

Yes. That seems a little high on the usage for just hot water. My PB105 usually uses about 2 bags per week during the summer for just hot water. Right now it's higher because some is being used for heat at night and early mornings.

My Boiler-mate is set to just under 120F.
I'm using more than 2 bags a week right now though.

best setting to save fuel? OFF The best way to heat hot water is a heat pump HW heater. (summer operation ONLY) With the use of the HW heater it eliminates the necessity of a de-humidifier ( necessary for most homes) so for all intents and purposes your hot water is free. winter use is not recommended (by me)