Table F: Boiler Temperatures and Minimum Pipe Size at Varying Return Temperatures
System
R
eturn Temp Su
pp
l
y
T
emp
1
S
u
p
p
l
y
T
em
p
1
Su
pp
l
y
T
em
p
1
(
°F) (°F) <80' equiv. 80-200' equiv. (°F) <80' equiv. 80-200' equiv. (°F) <80' equiv. 80-200' equiv.
6
0 138 2"NPT 2 1/2"NPT 147 2"NPT 2 1/2"NPT 154 2"NPT 2 1/2"NPT
8
0 138 2"NPT 2 1/2"NPT 147 2"NPT 2 1/2"NPT 154 2 1/2"NPT 3"NPT
1
00 138 2 1/2"NPT 3"NPT 147 2 1/2"NPT 3"NPT 154 2 1/2"NPT 3"NPT
120 145 2 1/2"NPT 3"NPT 158 2 1/2"NPT 3"NPT 170 2 1/2"NPT 3"NPT
1
40 165 2 1/2"NPT 3"NPT 178 2 1/2"NPT 3"NPT 190 2 1/2"NPT 3"NPT
1
60 185 2 1/2"NPT 3"NPT 198 2 1/2"NPT 3"NPT 210 2 1/2"NPT 3"NPT
1
-Approximate high fire heater outlet temperature based on the standard heater pump and the recommended connecting pipe
s
ize.
M
odel 1005
M
inimum Pi
e Size
2
M
odel 1505
M
inimum Pi
e
Size
2
M
odel 2005
M
inimum Pi
Fig. 14: Single Heater with Primary/Secondary Piping
Fig. 15: Dual Heaters (Reverse/Return)
with Primary/Secondary Piping
Fig. 16: Single Domestic Hot Water Heater and Storage
Tank
16
Domestic Hot Water
When designing the hot water piping system for
domestic hot water applications, water hardness
should be considered. See Table H on page 18 for the
required tubing sizes and expected supply tempera-
tures for different operating conditions. Water
hardness is expressed in grains per gallon.
Fitting Type
Equivalent Length (ft)
2-1/2” NPT 3” NPT
90° Elbow (Std.) 8.5 9.4
90° Elbow (Long rad.) 3.5 3.6
45° Elbow 3.0 3.4
Gate Valve (Full open) 1.6 1.6
Swing Check Valve 22 25
Table G: Equivalent Lengths of Pipe for Typical Fittings
Note: Equivalent lengths are calculated based on typical operating
conditions with typical Schedule 40 pipe fittings and valves.
Equivalent lengths are approximate and may vary greatly.
*Maximum 4 times the pipe diameter or 12”, whichever is less.
*Maximum 4 times the pipe diameter or 12”, whichever is less.
