Wood Shop unit heater piping

Michael B

the info about books...I have them already. This is an existing system so I just wanted a second or third set of eyballs on it. I figured out the balancing but the big question was wheather I needed a circ. on the main supply line...

Michael B

wood shop piping

Enclosed please find a drawing a customer sent over of an existing wood shop with Hydronic Unit Heaters. I have a few questions.

1) Do we need circ. on first 3 unit heaters?
2) Do they need pump on main 2" supply line?
3) If each boiler is 300,000 BTU's do I need PL pumps for riser into supply?
4) Any other thoughts you guys might have?

Gary Fereday

Easy answer

To your questions is 'Get and read Dans books on heating at Books & More here on this site". you'd do well to look at the other things on the pipe on the left.
Right off the bat, you have about 20% less water avalible for your heaters than you need. 2. you will have a difficult time balancing the system if it is piped as shown. That is; the first unit heater will work ok the rest will be having a tough time getting water flow. 3. the pumps will not lift the water to the unit heaters, the pressure will do that. anyway bigugh

Earthfire

Ideally

I'd make it into a primary secondary system. Put a circ on the primary. install a cross over between the supply and return and tap the unit off the crossover with close spaced tees. An make the return main a reverse return. that setup will give you even supply temps to all the units and more balanced flow thru the units. At the least I'd change the piping to a reverse return.