American Water Heater GTS-705-PEA Benutzerhandbuch

The following applies when using tankless water heaters to recover a storage tank.            
Drawing WH-1-B is an example. 

Tankless water heaters have a pressure loss which must be 

             considered in the system design.  

Reference the pressure loss curve for the heater model being used to determine the pump size for the

  

desired recovery rate. 

For recommended pump sizes use the table below.  Additional pressure losses in plumbing between the 
Heater(s) and the storage tank must also be taken into consideration. 

The specified pump size is to provide maximum recovery of the storage tank.  A smaller pump size may 
be used, but could result in longer recovery time of the tank.  Please contact the Tech Services department 
with any questions on pump sizing.  

NOTE: 

Only use pumps of brass or stainless steel construction.  Do not use pumps of iron 
construction as they will oxidize and clog the inlet filter on the appliance. 

Pump Sizing for Storage Tank Application 

7

Number of 

Tankless

Water Heaters 

 

1 

6 gpm @ 30' head 

5 gpm @ 25' head 

2 

12 gpm @ 30' head 

10 gpm @ 25' head 

3 

18 gpm @ 30' head 

15 gpm @ 25' head 

4 

24 gpm @ 30' head 

20 gpm @ 25' head 

5 

30 gpm @ 30' head 

25 gpm @ 25' head 

6 

36 gpm @ 30' head 

30 gpm @ 25' head 

7 

42 gpm @ 30' head 

35 gpm @ 25' head 

8 

48 gpm @ 30' head 

40 gpm @ 25' head 

9 

54 gpm @ 30' head 

45 gpm @ 25' head 

10 

60 gpm @ 30' head 

50 gpm @ 25' head 

11 

66 gpm @ 30' head 

55 gpm @ 25' head 

12 

72 gpm @ 30' head 

60 gpm @ 25' head 

13 

78 gpm @ 30' head 

65 gpm @ 25' head 

14 

84 gpm @ 30' head 

70 gpm @ 25' head 

15 

90 gpm @ 30' head 

75 gpm @ 25' head