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PB 105 Install, Do's and Don'ts

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by pellethound, Jun 8, 2014.

  1. pellethound

    pellethound New Member

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    I am currently new to pellets, just traded my 3 1/2 year old coal stoker for a 1 year old PB105. My stoker was in my barn but Im putting this unit in the basement. I would like to hear the do's and don'ts for installing this unit. This boiler was manufactured in august or sept. of last year and it has the burn pot bubble starting, the former owner said he put 13 ton through it this past winter. Is Harman trying to use up all the older burn pots before making customers happy with the new style? I was well aware of the issue and chose to take the unit anyway. Also can I run my blue wire to the circulator to use my whole system as a dump zone which is what I want to do because I dont have my house zoned and its a very old gravity setup. My circulator is a Taco 009, glad to be on these forums didnt know they existed till a few days ago, up until then I was always on nepacrossroads forums. Thanks for any info and Im sure Ill have some ?s along the way

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  2. __dan

    __dan Feeling the Heat

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    There are more than a few PB 105 owners on the board here so you should get some responses.

    I don't have the PB105, never seen one, but what I am aware of comes from reading user reported problems and looking at the manual.

    You will need boiler return water protection to maintain the return water above the condensing temp or ~ 140F. The manual may mention this briefly or skate past it.

    Don't know anything about that blue wire or how Harmon implements a dump zone, but the last time I looked at the PB105 manual, there was no labeled terminal connection for an external operating or thermostat control. It looked like the factory control implementation was the manual on/off switch on the boiler and the supply water aquastat. If this is so, the boiler would be seasonally "on" and maintain hot at the lower differential of the aquastat. This would add substantial run time, fuel consumption, to maintain the boiler hot when there is no call for heat from the zones. Potentially, calling the house circ on overheat dump zone could potentially call the burner to fire as it cools.

    I know how to makes the boiler controls play the national anthem when you walk in the room, but as a license holder it would be illegal for me to not follow the manufacturer's instructions. It looked like I it would have to be an approved engineering change, so Harmon should take some heat for it imo.

    Those two things. Boiler return water protection and the "on" condition (the call for heat) being a tiny manual switch on the boiler are two big ones in my view.

    It may have a problem with the "off" condition also if it is smoldering the remaining fuel as the aquastat turns the unit off. Users report creosote, which there should be none of in a modern wood burning appliance.
  3. pellethound

    pellethound New Member

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    Seasonally on is great for me, the coal stoker I had wasnt capable, with this unit when its warm during the day and chilly at night i can flip the switch, no such thing with the coal stoker I had you either burned or ya didnt. So I should put in a mixing valve to favor the return water and keep it at 140? yes it did mention that in the manual, how does that level out though you take hot from your supply to favor your return isnt that kind of defeating the purpose?
    Last edited by a moderator: Jun 8, 2014
  4. __dan

    __dan Feeling the Heat

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    Seasonally on is actually terrible. The boiler will short cycle to maintain itself hot even when there is no demand. It is only heating up the flue and the flue gas. Harmon should take some heat over that. What it eats in extra pellets to do that would buy a house payment. Plus, the short cycling will make creosote and require more cleaning.

    Return water protection, it will temper the cooler return water with supply water. There are different ways to do it but you should look at a loading unit like the Acaso LK 810. Depending on the load type, there is a time delay before the loads are returning hot water when the circ is called.
  5. pellethound

    pellethound New Member

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    Why a loading unit over a mixing valve? Im not familiar with loading units and dont intend to have a supply tank...
  6. __dan

    __dan Feeling the Heat

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    Yep, you could probably do it with a primary secondary pumped loop, secondary loop with outdoor air reset and boiler return protection built into the reset controller. The OAT reset controller controls the three way mixing valve or injection pump and loads the boiler only as the boiler return is above setpoint.
  7. __dan

    __dan Feeling the Heat

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    Loading unit has the boiler circ and thermostatic mixing valve built together in one unit.
  8. wil lanfear

    wil lanfear Feeling the Heat

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    I have mine wired with the blue wire to power a low voltage transformer in a overheat situation, 2 wire cable to a relay with a low voltage coil which when powered will run a circulator heating my workshop. The burnpot in the unit that you bought still should be under warranty if the seller did a warranty transfer to you. I'm not sure what you are asking for, "dos and dont's", operation of boiler or installation?
  9. pellethound

    pellethound New Member

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    I didnt know anything about the warranty transfer I just read in the book it transfers over...do you know what i need to do to transfer it? How did you maintain your return water to keep it above 140?
  10. wil lanfear

    wil lanfear Feeling the Heat

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    I don't really know know how the transfer of warranty is done but..... I expect it has to be done through the original dealer that sold the boiler. I have my boiler piped in parallel with my oil boiler using a circulator which is controlled by an aqustat in the oil boiler to maintain 180* in both boilers. This works great for me, boiler temps never go below 140* with the low setting on the pellet boiler set to 160*. When we get into Dec., I run the pellet boiler in manual, pellet boiler never shuts down, always a minimal fire burning, you will need a dump loop to run in manual.

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