New installation issue

mattmia2

Your drawing looks better than what I do with cad software. I'd encourage you to read at least idronics 12, hydronic fundamentals and idronucs 2, air and dirt elimination in hydronic systems before tearing in to pipe.

Poolman21

> @hot_rod said:
> The pump in the boiler, it should be on the return side pumping into the boiler?
>
> The air purger is in a good spot, I'd move the expansion tank to the return of the secondary loop, this assures all circulators are pumping away from the PONPC. Assuming the boiler circulator is pumping into the return.
>
> That "horseshoe" loop pipe needs to be sized large enough to handle the total flow rates, one size bigger would not hurt as it does serve as part of the hydraulic separation, the expansion tank shown in the color schematic shows the expansion tank being referenced for all the circulators thru the generously sized piping.
>
> Avoid what we call a bull head tee, bottom left of the drawing where flows come from two directions on the run and go out the branch of a tee.


It may be on the return side. My mistake. I took the front door off and it's located right above the supply inlet so I assumed.

My air scoop has a tee on the bottom of it which ties into my fill line and also my expansion tank. Not really sure how to separate them. None of the drawings in my instruction manual shows the expansion tank on the cold side. Not challenging you, I came here for advice and am admittedly a novice, just looking for clarification.

All copper piping is 1" which the instructions say is sufficient. Does that sound reasonable to you?

I will rotate that tee so a return enters the bottom and the branch, then goes straight up to my closely spaced tees.

Thanks for all the help.

Poolman21

> @mattmia2 said:
> Your drawing looks better than what I do with cad software. I'd encourage you to read at least idronics 12, hydronic fundamentals and idronucs 2, air and dirt elimination in hydronic systems before tearing in to pipe.

Got some free time now so I'll check it out. Thank you.

hot_rod

Poolman21 said:

> @hot_rod said:

> The pump in the boiler, it should be on the return side pumping into the boiler?

>

> The air purger is in a good spot, I'd move the expansion tank to the return of the secondary loop, this assures all circulators are pumping away from the PONPC. Assuming the boiler circulator is pumping into the return.

>

> That "horseshoe" loop pipe needs to be sized large enough to handle the total flow rates, one size bigger would not hurt as it does serve as part of the hydraulic separation, the expansion tank shown in the color schematic shows the expansion tank being referenced for all the circulators thru the generously sized piping.

>

> Avoid what we call a bull head tee, bottom left of the drawing where flows come from two directions on the run and go out the branch of a tee.





It may be on the return side. My mistake. I took the front door off and it's located right above the supply inlet so I assumed.



My air scoop has a tee on the bottom of it which ties into my fill line and also my expansion tank. Not really sure how to separate them. None of the drawings in my instruction manual shows the expansion tank on the cold side. Not challenging you, I came here for advice and am admittedly a novice, just looking for clarification.



All copper piping is 1" which the instructions say is sufficient. Does that sound reasonable to you?



I will rotate that tee so a return enters the bottom and the branch, then goes straight up to my closely spaced tees.



Thanks for all the help.

The expansion tank has two jobs, accept the expansion of the fluid as it is heated, and its location in the piping establishes the point of no pressure change PONPC.

Probably the best explanation of PONPC is found in this book, available at the bookstore here.

mattmia2

The bottom line is that the best place to put the air separator and the expansion tank is between the outlet of the heat exchanger in the boiler and the pump out of the boiler but you can't do that because it is a combi and the pump is inside the boiler so you need to be more careful about how other decisions affect air elimination and pressure differentials in the system.

hot_rod

There are some instances when having the expansion tank connected one the purger makes sense, This Pumping Away drawing that Dan promoted back in 1994 still works. In some applications.

With high pressure drop appliances, boilers, heat pumps, etc you need to look more carefully at the best PONPC.

Always you want the air purger at the highest temperature location, but not the tank.

You can profile what goes on in the circuit by putting numbers to it. The dotted red line is basically the ∆P the circulator adds.

This example shows a system with multiple circulators, the boiler and indirect. The integral checks in both circs prevented the indirect circ from seeing the PONPC in the case of a call for flow to indirect. You have locked off access to the expansion tank connection due to the check in the heating circ.

Notice how moving the tank (PONPC) to the suction she of the indirect changes then profile of the ∆P that is being added by the circ, pumping away, the entire circuit see an increase in pressure via the dynamic, ∆P, added bon the circ now pumping way.

hot_rod

These are examples of where the expansion tank is not at the air purger, assuring the ∆P from any/ all circs is added not subtracted from the loop or circuits.