boiler plumbing review

[CRIV911]

I am installing a Harmon PB-105 pellet boiler with 240 gallons of buffer storage. I am a contractor, but not a heating specialist. I have a little knowledge,but I could use some guidance. My goals are to heat from the buffer tanks when possible. Then charge the tanks from the boiler. Finally, heat from the boiler when demand is too great for the tanks.My heat loss calcs are 39000Btu. Boiler output 113900Btu. 240 gallons of water should yeild 79000Btu's @ 40degree delta [180 to 140]. That should give me 2 hours of heat even on the coldest day of the year. I have attached a drawing for reference. It is to scale, so it literally represents what I would be piping. My questions are:

1.Does this look right in general?
2.If you look closely there are two primary circuits running clockwise[boiler], and counter clockwise[buffers]. A third would be the boiler charging the tanks running clockwise.
Will the pull of the circs create the flow as I suspect?
3. I want to use one of the new adjusting pumps such as a grundfos alpha, is it necessary or even wise to use them in all three positions?
4. In the drawing I have a mixing valve at the boiler return. In retrospect I believe a diverter valve at the T above the #3 pump is a better location.
5.Should the boiler pump could be relocated to the return side of the boiler?

Thanks for any help. I am open to direction on this project. I do have a wife and daughter that will be asking for heat soon, so time is of the essence. I also need help with incidentals, such as piping diameter, purge valves, air eliminators, ect.

 

[NCPABill]

I wish I was smarter and could help you out. Having just muddles my way through an install of a BioMass40 with storage, I understand your pain, but the fact remains that I am not the person whose advice should be taken.

Now the advice, which isn't going to help... Read the Simplest Design sticky not to replicate the layout, but to understand the concepts. Then you can build what you need with the same principles. I got to the point where I was pretty sure I knew what I wanted, and could then ask more specific questions.

Sincerely, best of luck with your project,

Bill

 

[CRIV911]

I have read and reread the simplest design thread. I believe that if you unfold my layout you will much of that design. Simplest charges and pulls from the top of the tanks. So does mine [hopefully]. Simplest returns from the bottom of the tank, and the load circuit, so does mine[I think]. I am fairly confident that I can create something that will work. I want it to work as well as is possible. If I were to feed the tanks from the bottom, and take from the top that would be simple. Charging from the bottom isn't ideal, and I know that. So I am left with these two primary circuits running clockwise and counter clockwise. It's were the split at the top and bottom that I am concerned. The tanks have to reverse flow. The main trunk line that feeds the two close T's does not. I'm losing daylight I need a torch this cave is getting dark.

 

[Hunderliggur]

I am installing a Harmon PB-105 pellet boiler with 240 gallons of buffer storage. I am a contractor, but not a heating specialist. I have a little knowledge,but I could use some guidance. My goals are to heat from the buffer tanks when possible. Then charge the tanks from the boiler. Finally, heat from the boiler when demand is too great for the tanks.My heat loss calcs are 39000Btu. Boiler output 113900Btu. 240 gallons of water should yeild 79000Btu's @ 40degree delta [180 to 140]. That should give me 2 hours of heat even on the coldest day of the year. I have attached a drawing for reference. It is to scale, so it literally represents what I would be piping. My questions are:

1.Does this look right in general?
2.If you look closely there are two primary circuits running clockwise[boiler], and counter clockwise[buffers]. A third would be the boiler charging the tanks running clockwise.
Will the pull of the circs create the flow as I suspect?
3. I want to use one of the new adjusting pumps such as a grundfos alpha, is it necessary or even wise to use them in all three positions?
4. In the drawing I have a mixing valve at the boiler return. In retrospect I believe a diverter valve at the T above the #3 pump is a better location.
5.Should the boiler pump could be relocated to the return side of the boiler?

Thanks for any help. I am open to direction on this project. I do have a wife and daughter that will be asking for heat soon, so time is of the essence. I also need help with incidentals, such as piping diameter, purge valves, air eliminators, ect.

You really want to follow the "Simplest Pressurized Storage" design https://www.hearth.com/econtent/index.php/forums/viewthread/19086/

You only need 2 circulators, not three. You may want the Alpha pumps, they were not available when I installed my system, and I am not sure they would buy me enough efficiency. You may want a flow check valve in the system to ensure the correct flow (like between the legs of the load side so that the load circulator just does not loop the return back to the supply).

You should have a return temp protection valve on the input to the boiler (Danfoss or equivalent). I would put the boiler circulator on the input side (between the Danfoss and the Boiler). You need a ball valve on the hot input to the mixing valve to balance the return (valve not shown in illustration).

Pipe size should be 1 1/4" for your boiler output I believe. Judicious use of unions and shutoff valves will make your life easier.

 

[CRIV911]

I don't see how I can get away with two circulators. Simplest doesn't have a secondary circuit to load. There needs to be a pump in that #2 location to pull the water into the T's. The #3 pump is probably better on return than supply. I'm not sure where you mean for the check. I reread simplest for the thousandth time. My goals are the same. I believe the only difference is the secondary circuit to the load, and necessary pump.

 

[CRIV911]

I could use the tanks as a primary loop, and the boiler and load circuits a secondary's. That would give me boiler protection without a mixing valve. The only downside I see with that is I would have to charge the tanks from the bottom, mixing the tank temps. The other way would feed to top, but pull cooler water of the bottom. I have looked at the primary secondary sticky. I don't see what purpose the buffer serves in that scenario. Help, my brain is getting a cramp.