Installation Instructions
APPLIANCE LOADS +GAS LOAD LENGTH OF RUN
FURNACE 75 CFH (75,000 BTUH/1000 PER CFH) 14 FEET
OVEN/RANGE 45 CFH (45,000 BTUH/1000 PER CFH) 20 FEET
DRYER 25 CFH (25,000 BTUH/1000 PER CFH) 38 FEET
WATER HEATER 24 CFH (24.000 BTUH/1000 PER CFH) 50 FEET
TOTAL..................................................169 CFH
LENGTH OF EACH RUN
A = 8 FEET EXAMPLE:
B = 10 FEET Furnace: A (8 ft) + F (6 ft) = 14 FEET
C = 12 FEET Oven/Range: A (8 ft) + B (10 ft) + E (2 ft) = 20 FEET
D = 20 FEET Dryer: A (8 ft) + B (10 ft) + C (12 ft) + G (8 ft) = 38 FEET
E = 2 FEET Water Heater: A (8 ft) + B (10 ft) + C (12 ft) + D (20 ft) = 50 FEET
F = 6 FEET THE LONGEST RUN IS FROM THE METER TO THE WATER HEATER; OVER 50 FEET.
G = 8 FEET
SIZING SECTION A:
Length A must be sized to handle the total load of all appliances and the total pressure drop from the meter to the farthest appliance. The
total appliance load is 169 CFH. Using the longest length sizing method, the length is 50 ft. to the water heater. Referring to Table 1, (6"
WC inlet pressure and 1/2" WC pressure drop) under the 50 ft. length column, we find that 1 inch size has the flow capacity exceeding
169 CFH (171 CFH). Use 1" tubing to run Section A.
SIZING SECTION B:
Section B must supply the water heater, dryer and range. The total pressure drop for the system is considered to be from the meter to the
water heater (farthest appliance). The total appliance load is 24+25+45 = 94 CFH. Using the longest length sizing method, the length is 50
ft. (distance from meter to water heater). Referring to Table 1 under the 50 ft. length column, we find that size 1 inch has flow capacity
over 94 CFH (171 CFH). Use 1" tubing to run Section B.
SIZING SECTION C:
Section C must supply the water heater and dryer. The total appliance load is 24+25 = 49 CFH. Using the longest length method, the
length is 50 ft.
Referring to Table 1 under the 50 ft. length column, we find that 3/4 inch has flow capacity above the 49 CFH (89 CFH) Use
3/4" tubing to run Section C.
SIZING SECTION D:
Section D must supply the water heater. The total appliance load is 24 CFH. Using the longest method, the length is 50 ft. Referring to
Table 1 under the 50 ft. length column, we find that 1/2 inch has flow capacity above 24 CFH (32 CFH). Use 1/2" tubing to run Section D.
SIZING SECTION E:
The total appliance load is 45 CFH. Using the longest length method, the length is 50 ft. Referring to Table 1 under 50 ft. length column,
we find that 3/4" has flow capacity above 45 CFH (89 CFH) Use 3/4" tubing to run Section E.
SIZING SECTION F:
The total appliance load is 75 CFH.
Using the longest length method, the length is 50 ft.
Ref
erring to Table 1 under 50 ft. length column,
we find that 3/4" has flo
w capacity abo
ve 75 CFH (89 CFH) Use 3/4" tubing to run Section F.
SIZING SECTION G:
The total appliance load is 25 CFH. Using the longest length method, the length is 50 ft. Referring to Table 1 under 50 ft. length column,
we find that 1/2" has flow capacity above 25 CFH (32 CFH) Use 1/2" tubing to run Section G.
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SIZING PROCEDURES PRO-FLEX
®
CSST, FLEXIBLE GAS TUBING
L
ONGEST LENGTH METHOD EXAMPLE #1
This is a low-pressure series system with four natural gas appliances. The utility
company supply pressure exiting the meter is 6 inches water column, and the maximum
a
llowable pressure drop across the longest length from the meter to the farthest
appliance is 1/2 inch water column. The gas supplied has a specified gravity of .60 and
an energy content of 1 cubic foot per hour equals 1,000 BTU per hour.
3.2 Sizing Methods and Examples