TableF: Boiler Temperatures and Minimum Pipe Size at Varying Return Temperatures

System
ReturnTemp SupplyTemp1SupplyTemp1SupplyTemp1
(°F) (°F) <80' equiv. 80-200'equiv. (°F) <80' equiv. 80-200'equiv. (°F) <80' equiv. 80-200'equiv.
60 138 2"NPT 2 1/2"NPT 147 2"NPT 2 1/2"NPT 154 2"NPT 2 1/2"NPT
80 138 2"NPT 2 1/2"NPT 147 2"NPT 2 1/2"NPT 154 2 1/2"NPT 3"NPT
100 138 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
140 165 2 1/2"NPT 3"NPT 178 2 1/2"NPT 3"NPT 190 2 1/2"NPT 3"NPT
160 185 2 1/2"NPT 3"NPT 198 2 1/2"NPT 3"NPT 210 2 1/2"NPT 3"NPT
1-Approximatehigh fire heater outlet temperature based on the standard heater pump and the recommended connectingpipe size.
Model1005
Minimum Pi
p
eSize2
Model 1505
Minimum Pi
p
eSize2
Model2005
Minimum Pi
p
eSize2
2-Minimum
p
i
p
esizebased on totale
q
uivalent feet of su
pp
l
y
andreturn
p
i
p
in
g
between the s
y
stemloo
p
andheater.

Fig. 14: Single Heater with Primary/Secondary Piping

Fig. 15: Dual Heaters (Reverse/Return)

with Primary/Secondary Piping

Fig. 16: Single Domestic Hot WaterHeater and Storage

Tank

16
Domestic Hot Water

When designing the hot water piping system for

domestic hot water applications, water hardness

should be considered. SeeTable H on page 18 for the

required tubing sizes and expected supply tempera-

tures for differe nt operating con ditions. 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

TableG: 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.
Equivalentlengths are approximate and may vary greatly.
*Maximum4 times the pipe diameter or 12”, whichever is less.
*Maximum4 times the pipe diameter or 12”, whichever is less.