tibikedad
ArboristSite Member
I forgot to answer the question about using 1.25 inch piping. Yes, increasing the length of the pipe will always add more head pressure, which translates into slower gallons/hour, and more electricity needed to run the pump at the desired flow rate. A 1/2 inch pipe is good for about 25,000 BTUs per hour. A 3/4 inch pipe will do a little more than 2 times that much (around 60K BTUs / hour). A 1 inch is good for about 120K, and a 1.25 inch is good for more than 180K BTUs/hour. Of course, these are maximum rates, and they will degrade as the head pressure increases. Practically, with a long run, unless you use a very large (and expensive pump), the one inch pipe will most likely give you less than 90K BTUs / hour.
Remember, these BTU numbers assume a 20 degree temperature loss. The greater the temperature difference, the more BTUs will transfer.
The plumber that installed my boiler used a combination of 1 inch and 1.25 inch pipe, and small Taco 007 pumps. I couldn't run more than 2 zones at a time if I wanted heat in all the zones. Once I upgraded to 1.25 inch pipe everywhere, and increased the pump size to the correct head/flow rate (Taco 012), I could run all 8 zones simultaneously with all the radiators too hot to touch.
When you size your pipes and pumps, make a diagram of each zone, the head and flow rate required / zone, and then add up the total flow rate. This will give you an idea of the size of the main pipe and pump you need.
I got the figures above from the following web site:
Flow Rate and Piping Size for a Solar Hot Water System | Solar Heating System Guide
Remember, these BTU numbers assume a 20 degree temperature loss. The greater the temperature difference, the more BTUs will transfer.
The plumber that installed my boiler used a combination of 1 inch and 1.25 inch pipe, and small Taco 007 pumps. I couldn't run more than 2 zones at a time if I wanted heat in all the zones. Once I upgraded to 1.25 inch pipe everywhere, and increased the pump size to the correct head/flow rate (Taco 012), I could run all 8 zones simultaneously with all the radiators too hot to touch.
When you size your pipes and pumps, make a diagram of each zone, the head and flow rate required / zone, and then add up the total flow rate. This will give you an idea of the size of the main pipe and pump you need.
I got the figures above from the following web site:
Flow Rate and Piping Size for a Solar Hot Water System | Solar Heating System Guide