16
Installation Manual
PART 3: SOLAR WATER HEATER INSTALLATION
(CONT’D)
BOILER BACK-UP HEAT EXCHANGER (SB MODELS ONLY)
To assure that you have the correct flow through the Boiler Back-Up Heat Exchanger, refer to the
chart above to size your circulator correctly to your boiler or auxiliary heat source. We recommend
a flow rate of 1 gpm for every 10,000 BTU based on a 20 degree temperature difference between the
supply and return of the Heat Exchanger.
Example: Boiler is 100,000 BTU output = 100,000 BTU
)
10,000 BTU = 10 gpm flow rate. The Heat
Exchanger at 10 gpm will require a circulator that will operate at 8 feet of friction.
Fig. 3-5
Pressure Drop
Solar Heat Exchanger / Boiler Back-Up
Contender Solar
0
2
4
6
8
10
12
14
Flow in GPM
Upper Coil
Feet of Fr
iction (Head)
Lower Coil
1
2
3
4
5
6
7
8
9
10
11
12
13
14
