location of main circulator

[SnaykeByte]

I think this has been discussed before, but I'm trying to decide where I need to put the circulator in my system. I have a CB 6048 on order due to arrive in November, I have already buried 1" PEX S & R. The boiler is about 100' from the water to air HX in the air handler with electric back up, and I plan to build my own side arm for DHW. From a maintenance point of view, I would like to put the 007 Taco I have planned in the house close to the HX. Would there be a problem with this? The boiler and HX in the house will be about the same elevation, so would this be an ok layout? Thanks in advance for any help/advise.

 

[Willman]

I do know from reading the posts of the pros here that piping (sizes) and circs are all a function of btus that need to be transfered.It depends on how many BTUs your boiler produces and how many are required by your loads. I do know there is a thread on the 1" piping. You should search for that topic and see that this is discussed plenty.
Will

 

[SnaykeByte]

My heat load is only about 100K or so right now, but I plan to add more heat load in the spring with a couple of out buildings, hence my choice in unit size. I think my pipe sizing is pretty close, I just can't decide about the locale of the pump.

 

[Sawyer]

My heat load is only about 100K or so right now, but I plan to add more heat load in the spring with a couple of out buildings, hence my choice in unit size. I think my pipe sizing is pretty close, I just can't decide about the locale of the pump.

When I calculated the head loss of 1" pex, 200' total loop, 10 gpm to transfer 100btu, I show 26' head. This would require a 0013 if my calculations are correct? I was also told that the maximum recomendation for 1" pex is 75,000btu.

 

[SnaykeByte]

Please elaborate on the 75K limit for 1" PEX.

 

[Sawyer]

Please elaborate on the 75K limit for 1" PEX.

I copied this from a previous thread: "Let’s start at the beginning. The first question you have to ask in any situation is what is the heat loss of the structure. From there you can determine flow rates required which will tell you tubing size, loop length, and circulator selection. From there you have to look at the type of equipment and heat emitter being used to select the right control set up.
Here’s some rules of thumb: rough but generally accepted as safe
The following flow rates will all develop about 6’ of head per 100’ of the corresponding tubing size.
Using a 20* drop you can figure that each gpm is good for 10,000 BTU of heat transfer.
1/2” = 2 gpm
3/4” = 4 gpm
1” = 8 gpm
1-1/4"= 15 gpm
1-1/2” = 22gpm
2” = 45gpm
Note that the 6’ of head is PER 100’ of tubing length. Taco or Grundfos’ website will have specs detailing the performance curve of the circ you’re using."

"You want to stay below 4 feet per second in residential systems, so you need to compare the pipe sizes and flow rates to that. Any pipe sizes that are small enough to push the velocity at that flow rate over 4 feet per second should be dropped from the list.
Next, you need to figure out the pipe length. Be a bit generous, and account for the head loss in the radiators, as well - it ends up as an equivalent length of pipe at different pipe sizes. Knowing the flow rate, you can find out the head loss for each pipe size at that flow rate and water temperature."

 

[jgrimm]

I think this has been discussed before, but I'm trying to decide where I need to put the circulator in my system. I have a CB 6048 on order due to arrive in November, I have already buried 1" PEX S & R. The boiler is about 100' from the water to air HX in the air handler with electric back up, and I plan to build my own side arm for DHW. From a maintenance point of view, I would like to put the 007 Taco I have planned in the house close to the HX. Would there be a problem with this? The boiler and HX in the house will be about the same elevation, so would this be an ok layout? Thanks in advance for any help/advise.

If you are using CB's ThermoPex and a 100k Hx, the equivalent pipe length is >300ft. Add a few elbows and valves and you could easily be above 350' equivalent pipe length. With a Taco 007 with 1" Pex you will only get 4.4-5.0 GPM, at that length.

Ask your CB dealer to consult his Hydronic Component Selction Guide and tell you what he comes up with.

To answer your original question, put the pump at the boiler and mount it as low as you can. Use a longer pipe from the tee. In an open system you want as head pressure on the suction side of the pump as you can get....But then again, your dealer should know this.