More Buffer Tanks

Zman

This is a design I have been working on that I thought I would toss out for feedback.
The House is about 2,300 square feet. The attached garage is 425 square feet.
Zone 3 will be phase 2 of the project and will be a combination of towel bar, TRV radiators and a low temp fan coil in garage.
At the moment, I have 2 questions.
The first is the age old delta T circ on the boiler. This boiler has the capability to control the speed of the boiler pump via 0-10 VDC, can any make recommendations on this?
The second question is the system sensor for the boiler. With this buffer tank setup, where would you put the system sensor? I am thinking it would go after P-3.
@Rich Swatton, thanks for the buffer tank post.
@Rich, The HTP-UFT would work well, I am just not willing to be their high altitude Guinea pig.
The 1 1/4" pipes at the buffer tank will be as short as possible.
The boiler will live in the attached garage. Everything goes else in the 4' crawl space.
Thanks
Carl

STEVEusaPA

If both pumps 1 & 3 are running, would you not get any flow thru the buffer, or is that the goal? Just curious

hot_rod

would P2 be better at the boiler pumping into it? maybe not a huge deal with that boiler, but it would be "pumping away" if installed at the return.

Zman

STEVEusaPA said:

If both pumps 1 & 3 are running, would you not get any flow thru the buffer, or is that the goal? Just curious

If P-1 is moving more water than P-3, the buffer tank will gain heat. If P-3 moves more than P-1 heat will be removed from the tank.If they match, the buffer tank is out of the picture.

The real goal is to minimize boiler cycles under low load conditions. My understanding is that this piping maximizes the buffer's capacity by encouraging stratification.

Zman

hot rod said:

would P2 be better at the boiler pumping into it? maybe not a huge deal with that boiler, but it would be "pumping away" if installed at the return.

I waffled on that a bit. I figured the coil in the indirect has the most resistance, so I was reluctant to put it on the return.

njtommy

You mean like this little guy here?

Zman

njtommy said:

You mean like this little guy here?

That's the cute little feller.
How do you like it?
How did you pipe it?

njtommy

@Zman I just got it this week. I bought the 4 pipe. I was going to pipe it that way, but not after reading Idronics 17 and Hot rods post. I think I'm going to 2 pipe it. I just makes more sense when running hydro air/ fan coil units.

As per the heat flow buffer tank. It looks really well made and Pretty well insulated.

I won't have time to install it for a few weeks.

Thinking about 2 piping it and use the other two pipes to preheat my hot water some how for my combi boiler.

hot_rod

njtommy said:

@Zman I just got it this week. I bought the 4 pipe. I was going to pipe it that way, but not after reading Idronics 17 and Hot rods post. I think I'm going to 2 pipe it. I just makes more sense when running hydro air/ fan coil units.



As per the heat flow buffer tank. It looks really well made and Pretty well insulated.



I won't have time to install it for a few weeks.



Thinking about 2 piping it and use the other two pipes to preheat my hot water some how for my combi boiler.

Not a bad plan to connect a FPHX on the spare ports, a small ECM, then run potable water through the B side of that flat plate. It would pre-heat or with enough HX surface serve as a DHW producer. I found a few sources for low flow switches to trigger on that FPHX pump, even a low lead version.

What size connection ports on that tank? I like the HeatFlo products.

njtommy

It's the 22 gallon. They are 1-1/4 ports.