Boiler Room layout advice

caryatid

Hi.

I have been struggling with my boiler room design for a few days. Suddenly it seemed to get really simple, which I hope is a good sign. I was wondering if you kind folks might be willing to look at it and tell me what mistakes I might have made.

I did a heat loss calc and sized the radiators with got some good free technical input from a local designer/installer who could not start work till December, hence my DIY status. I don't want to abuse his kindness and desire to stay out of my project now though. All that to say I believe the sizing of the rads and the boiler are good and I am happy with the pump choice and 1" piping size for the long manifold.

Thank you!

Here is the diagram:

JUGHNE

I assume there is a circ inside the boiler?

IIWM, I would add the air inlet/exhaust piping to the diagram.
Also the gas line and cond drain. This may avoid surprises. A side elevation for clearances also may save some grief.

Maybe lower the drain hose bib to empty more water out.

And if you have the wall room I would keep components low enough to service without a ladder.

I see now that this is a combi. So add the HW, CW and pop off valve drops for both sides.

caryatid

Thank you Jughne.

To answer your points, in case it brings up more questions:

- Yes, there is a circ pump in the boiler.
- I agree I need to also work out the air intake, flue, gas, condensate, and domestic hot and cold lines. I wanted to be sure that I understood the boiler piping correctly before I moved on the the 3D complications.
- There is a lower hose bib, between the purge Tee and the union on the return side, right at the bottom.
- The whole room is only 7' tall, so nothing is up high.

The things I was most concerned about as a DIYer is that I have the components in their correct places relative to one another AND that the closely spaced Tees will work as they should where I have put them. Also that I haven't overlooked something vital.

I have a few more questions now:

- Are the unions in a good place for the boiler?
- Do I want unions for the DirtMag and air vent? Or do those last forever?
- Are there specialty service valves for the supply and return ports for the boiler loop, like there are for the DHW loop? I can't seem to find any when I google around.
- Where would temp/pressure gauges be most useful? I believe the boiler will tell me supply and return temps on its info screen.

hot_rod

I'd rather the expansion tank and fill on the right side, return (blue piping) then both circs are truly pumping away.

Air sep stays where you show it.
Skip the unions
Boiler has S&R temperature readout, maybe a temperature gauge downstream of the system circulator, it reads mixed temperature. The boiler sys sensor located there will read SWT also and control more accurately.

caryatid

Thank you Hot Rod.
I will switch the fill line to the return piping and put a temperature gauge after the system circulator.

I believe that it is important to pump away from the expansion tank, I have heard it a few times now (though I forgot about the internal pump on this diagram), but I don't know why. Could you tell me?

caryatid

Here is the new diagram

mattmia2

2 reasons to pump away.
1. If you are pumping in to the expansion tank you are putting that pressure in to the tank instead of the system.
2. You are creating the lowest pressure at the expansion tank and air eliminator where the lowest pressure will encourage any dissolved air to come out of solution at the air eliminator.

caryatid

Thank you!

STEVEusaPA

mattmia2 said:

2 reasons to pump away.
1. If you are pumping in to the expansion tank you are putting that pressure in to the tank instead of the system.
2. You are creating the lowest pressure at the expansion tank and air eliminator where the lowest pressure will encourage any dissolved air to come out of solution at the air eliminator.

1. If you are pumping at the expansion tank, the point of no pressure change, you aren’t adding pressure to the tank. The tank stays the same pressure. Water circulates by pressure differential. You are dropping the pressure in the rest of the system.
2. Also wrong.See my #1.
https://youtu.be/tZRuqiQkukE