Installation Guide
18
Sizing and Congurations
400 CFH, which at 70 feet can be supplied by 1¼" pipe with a maximum capacity
of 490 CFH. 1¼" pipe is the correct size for section A2.
• To size section A3, we can reduce the load by another 190 CFH to 210 CFH for the
remaining heater and the water heater. At 70-feet, 1" pipe can supply a maximum
of 240 CFH, which is sucient for the run. 1" pipe is the correct size.
• To size section A4, the load is reduced to just the 60 CFH of the water heater. At
70-feet, ½" pipe can provide a maximum capacity of 61 CFH. ½" pipe is the correct
size for section A4.
Step 2 Size Section E: The length is the length of the black pipe plus the length of the
HOME-FLEX® run = 70 feet, and total load is 60 CFH. Referencing Table 7.1, ¾" tubing provides
a maximum capacity of 76 CFH at 70 feet. ¾" Tubing is the correct size for section E.
Step 3 Size Section D: The length is the length of the black pipe up to the branch and the
length of the HOME-FLEX® run = A1 + A2 + A3 + D = 60 feet. Load is the load of the heater,
150 CFH. At 60 feet, 1" inch CSST can provide a maximum capacity of 156 CFH. 1" is the correct
size.
Step 4 Size Section C: The length is 40 feet and total load is 190 CFH. At 40 feet, 1" tubing
provides a maximum of 195 CFH. 1" Tubing is the correct size.
Step 5 Size Section B: The length is 20 feet and total load is 200 CFH. At 20 feet, 1" tubing is
required to provide at least 200 CFH, with a maximum capacity of 288 CFH.