AMPW 400-1000L I&O Manual
43
. Water Piping
(continued)
G. Pump Selection
A Circulation pump is a required component for complete installation of this appliance. Choosing the appropriate
pump is critical for the functionality, safe operation, and longevity of the appliance. Pumps should be sized for each
particular installation based on the required flow rate, water hardness, and total pressure drop in the primary loop
between the tank and the water heater.
1. Sizing a sufficient pump will ensure the desired temperature rise and meet the minimum flow rate requirements.
Lower flow rates will allow build up of scale and cause more stress on the heat exchanger.
a. If the flow rate is too high and the temperature rise is too low, the flow rate can be decreased by adding a
restriction in the loop.
i. Install a ball valve or globe valve (recommended) in the outlet side of the primary piping.
ii. With the water heater at its maximum input rate (high fire), slowly adjust the globe valve until the temperature
rise is within the recommended range shown in
.
iii. Water velocities too high may cause erosion within the tubes of the heat exchanger or the primary piping.
Failure to adjust the flow rate to the specified values or use the appropriate pipe size can cause non-warrantable
damage.
2. The wetted materials of the pump must be suitable for potable water. Look for bronze or stainless steel pump
housings.
AMPW
Model
Nominal
Pipe Size
(in.)
Water
Hardness
(gpg)
Flow
Rate
(GPM)
Heat Ex.
loss
(ft of head)
System
Total Loss
(ft of head)
Optional Grundfos
Pump
Pump TS
Part #
Temp.
Rise (
0
F)
400
2
4-12
27.3
6.8
9
UP 43-44 BF
111355-01
28
2
12-15
36.7
11.2
16
MAGNA1 32-100 FN
111355-04
21
500
2
4-12
32.8
6.9
10
MAGNA1 32-100 FN
111355-04
30
2.5
12-15
44
11.5
14
MAGNA1 50-80 FN
111355-03
22
650
2.5
4-12
43.7
6.5
9
MAGNA1 50-80 FN
111355-03
29
2.5
12-15
58.6
10.4
14
MAGNA1 50-80 FN
111355-03
22
800
3
4-12
54.6
7.6
9
MAGNA1 50-80 FN
111355-03
28
3
12-15
73.3
11.8
15
MAGNA1 50-80 FN
111355-03
21
1000L
3
4-12
65.5
7.4
10
MAGNA1 50-80 FN
111355-03
30
3
12-15
88
12.3
17
MAGNA1 50-150 FN
109695-02
22
NOTE:
The total loss includes 50 ft of pipe, 8 elbows, and 4 Valves.
Table 23: Pumps, Pipe Size, and Total Head Loss
NOTICE
NOTICE
It is the installer's or system designer's responsibility to account for differ
-
ences in the circulation loop. Length, pipe diameter, elbows, and valves all
contribute to the total pressure drop in the loop.
