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[smaxwell]

Hello Everyone,

I've got a plan and need some confirmation that it's going to work.

I have PEX-Flex with 1" ID inner pipes coming into my basement, 170 feet from my OWB. My plan is to use 45 feet of 1" PEX to travel through my basement over to a sidearm (3/4" inlet and outlet sizes) on my electric water heater, then 45 feet back to a flat plate heat exchanger that delivers heat to a radiant infloor system and an iron rad system. The basement is unheated, but I'll be putting lots of insulation on the 1" PEX lines as they travel to and from the water heater. The hot water circulating through the sidearm and one side of the flat plate exchanger is part of the main loop that goes back and forth to the OWB. The radiant infloor system and iron rad system will be part of closed loops on the other side of the flat plate exchanger.

Will this set-up deliver enough heat to the radiant and iron rad side of my system? Should I be concerned that the 3/4" fittings on the side arm will restrict hot water flow too much? Will the heat siphoned off my the side arm to the water heater limit the heat delivered through the flat plate exchanger to the rest of my house?

I'm thinking that this set-up should work fine, but just need some confirmation from experienced OWB owners before I set it all up.

Thank you all very much!

Steve

[Bill G]

Steve,

     Think you should "tee" off incoming main line to side-arm, then back into incoming main line down stream, using another "tee".  This will allow the 1" to remain full ID and shouldn't affect flow.  Just need to be sure pump will handle extra bit of load.

      Hopefully, someone with more knowledge will chime in and offer a better explanation.

Bill

[muffin]

Similar to the previous post, put a bypass in around the sidearm.  Then you can adjust how much water is diverted around to keep your flow.

[Trint]

First off 1in pex is not 1in ID it is much closer to 3/4" pipe, if you are running across the room for the hot water only I agree with Bill teeing off might be a better option, this is the setup I have.  As far a heat loss the side are and flat plate will loose more heat than the pex will.

I attached a picture of my setup, my 1in ID lines come in next to the boiler then I tee to 1in pex (white) for the oil burner and 3/4in pex(red) for the hot water that runs across the room about 20' to the side arm and tee back in before the filter after the boiler and has a valve to regulate flow to the side arm, only have it half open normally.

Joe

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[martyinmi]

1" Pex-Flex has a 1.032" I.D. and a 1.26" O.D.

[RSI]

Going from 1" pex to 3/4" copper for just a small length won't make any difference. 3/4" copper is bigger inside than pex fittings. (barb type) It is long lengths of the smaller diameter that will cause restriction.

I would run all the water through the sidearm first. You want the hottest water possible for the sidearm to work best. It won't be taking much heat off and you probably won't even notice it on the other heat exchangers.

[smaxwell]

Thanks for all your help, everyone!

Much appreciated.

Bye for now,

Steve