Forced Hot Water System Layout

Brent H.

So I'm getting ready to add about 3 zones to my heating system to support an addition. My current system has a tankless coil and 3 circulator controlled zones in a pull configuration. I'd like to reconfigure to support an indirect hot water heater with one circulator and then 6 zones usings zone valves and a variable speed circulator with a delta T sensor. All of this configured in a pump/push setup. So here are the questions I have:

1. My current system steps down from 1.25 inch pipe to 1 inch pipe after the domestic water feed T on the supply side. The return side with the circulators stays at 1.25 inch. Is there some reason the supply steps down to 1 inch?

2. In my reconfigured system, I assume I would run from the boiler, through the water feed, through the air scoop, then split to the 2 circulators, and then the variable speed circulator would have the zone valves before running to the baseboard. On the return side I don't believe I need anything (besides ball valves & drains) as long as I use circulators with integrated flow checks. Is this correct?

3. I'd like to install the zone valves and circulators on a panel about 6 feet to the left of the boiler. Is this distance a problem? My reason for this is it will put it out of the way and also allow for easier replumbing/reuse in the future when I get a new boiler(which I'm due for in the next couple of years).

4. With the push setup I'm proposing, what keeps the variable speed ciculator from drawing water through the indirect circulator?

As always, thank for the help.

Marc_17

The size of the pipe would depend on the flow rate and amount of heat you want to transfer. 1" pipe @ typical flow rates is good to approx 100K BTU. There should be links to the exact rates around on the wall somewhere.

2). Correct. Some people prefer to put the zone valves on the return side, so its an option if the layout works better that way for you.

3). Location should't be an issue.

4). Both your heating Circ and DHW circ should have flow checks, if you have the flow check in the DHW circ, then that will stop the heating circ from drawing from the DHW circuit. Some systems would even be wired priority depending on the size of your boiler, which would close the zone valves and turn of the heating circ during a DHW call.


My system is very similar to this. My DHW circ didn't have a flocheck in it, so I added a honeywell flow check to the line instead.

Brent H.

Followup

Thanks for the info. A few followup questions:

1. Is there any benefit gained by using a smaller size diameter pipe on the supply then the return? On the opposite side.... is there anything lost if 1.25 inch pipe is used on both supply and return?

2. I'd like to run copper instead of iron pipe over to my distribution panel. I assume that there is no problem with this.

Thanks again.

klaus

1). None that I know of. Size the pipe to the load/flow, anyting larger is really just wasting money on larger pipe and fittings.

2). Copper is fine. If you plan on using copper, you will see that oversizing the pipe will get expensive fast. 1.25 copper fittings and pipe aren't cheap.

Mark Custis

buy:

Pumping away at the book store here.

ChasMan

Yes

But not just buy it. Read the darn thing. And read it all. Even if half of it does not apply to your situation. Like plumbing zone valves so they don;t act like air seperators. Thats good advice and I see noone here follows it.