Taco Pump sizing, hydronic heating

[Rnbuck01]

I was doing some math for a pump size for my system. I have 6 loops of 250 ft. Am i better off with going with the 006 or the 007 ? I will be using at least a 40 gallon water heater. Dont want to have any excess noise while running the system.

 

[2000xpsd]

You have to do some more math to figure out your heat loss and head pressure... Then you can use taco's pump app http://www.taco-hvac.com/wizard_pumps.html

 

[engineer2]

There are several versions of the Taco 006 pumps with different flow rates. I've got a Taco 006-B4 feeding 500 sq ft of basement. Don't remember how many feet of oxygen barrier PEX tubing it was (500 ft?). I have two parallel counterflow loops. I estimated flow to be about 6 gpm, and with the measured temperature drop, I'm using 10,000 to 12,000 BTUs. Note an insulated garage might require twice as many BTUs.

My heat source is the 50 gas water heater for the house. This isn't to code (potable water can't be heating water), but if I finish the rest of the basement I will do a separate water heater.
It's a very simple system. Salvaged a 24V transformer and relay from an old furnace and control it with a used programmable thermostat. A fancy preconfigured manifold and boiler are vast overkill for a small system. The system has been silent and trouble-free for 12 years.

 

[Rnbuck01]

I am figuring that my head feet is around 5-6 then you add 2 more feet to get 7 head feet. It's a 1500 square foot building.

 

[engineer2]

Figure out how many BTUs you need and work backwards to a flow rate. You need to estimate your inlet/outlet temperature drop, which varies with climate, system design and loop length, but is typically designed to be 20°F.

In our Chicago climate assuming an insulated garage, 12,000 BTU per car space is a ballpark estimate for a conventional gas heater.

1500 sqft is pretty good sized, I don't think a 40 gal water heater would keep up, at least in Chicago. I'd be looking at over 62,000 BTU for our climate.
I'm sure some experts here will chime in.

 

[Rnbuck01]

So let's say 60,000 btu needed would be 6 gallons a minute. .75 head feet per loop x 6 is 4.5 feet then + 2 would be close to 7 head feet.

 

[2000xpsd]

If your calcs are right and you want 6gpm @ 7'psi th n I'd go with a 007. A 006 is too small, could get away with a 006b but a 007 will give you a little safety margin

 

[Rnbuck01]

I'd think it would dump the water heater out too fast if you go any higer.