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[andyjs]

I have 150' run to the house with logstor dual pex it has true 1 inch diameter.another 120 feet total in house that is 1" copper pipe with 26 90 degree elbows that feeds a side arm on hot water tank then a 20x20 heat exchanger in furnace and a 12x12 heat exchanger hanging unit in garage.wanting to put a delta t pump on the boiler and need help sizing and what brand is good? Thanks

[Sprinter]

Is it one big loop?

What are the btu rating for each exchanger. Technically they will want their own supply temp. Or hillbilly method of hottest exchanger first #1 HE needs 180 then next needs 160-155 then the next needs 140 in and 120 out. For example. In order for each device to putout it's rated btu. Even then that would be a huge delta T for the boiler to see and most likely below its rated min temp. I'm a buffer tank and ECM circ guy as you probably have read. With 1" pex max recommended flow is 7-8 GPM but 4-5 GPM is best.

Is that really 26-1" elbows?  Either way a delta T pump will sense the change in btu by change in delta T. So it will supply more as the house pulls more btu out of the system. What pump do you have now and what temp differential do you have when all HE are calling?
Taco is the only way to go with a VDT pump. Double 00 series VDT. 006 thru 0013

[andyjs]

It is one loop.I had a wilo 21fx 3 speed on my old boiler and it worked fine was only getting 2-3 degrees from sidearm 14 from furnace heat exchanger and never tested garage exchanger.but just bought a new furnace and wanting to go with the right pump

[LittleJohn]

...1" pex max recommended flow is 7-8 GPM but 4-5 GPM is best...

Actually you can run 1" PEX up to 14GPM and still be below 8ft/s (typical point were erosion happens in a metal, i.e. Cu piped system); please note at this kind of volume you are also looking at some pretty big head loss numbers. 

[andyjs]

My pex is 1" inside diameter so same as 1 1/4 us pex

[LittleJohn]

Using math again, 1" Cu - Max GPM about 9-10 gpm; again to stay away from an erosion situation in metal.

[Sprinter]

What speed worked for you or for the exchangers? That pump covers a pretty wide range, like a 007 to a 009 just about. What did it do on speed 1 and spd 3. Delta T at boiler and where it hit sidearm.
I assume there is temp protection on the WH since it always sees flow

[andyjs]

I ran it on 3. I just ordered a Armstrong e9 I talked to Scott he said that would fit my application the best