Design Manual

14 R-TRWH-E-02 Rev D
The following applies when using Rinnai tankless water heaters to recover a storage tank. Drawing WH1-BC is an
example.
Rinnai Tankless water heaters have a pressure loss which must be considered in the system design. Reference the
pressure loss curve for the Rinnai 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 Rinnai(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 engineering department with any questions on pump
sizing.
NOTE: Only use pumps of brass, bronze, 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
Pump Flow Requirements
Number of Rinnai
Water Heaters
R94LSi/e, RL94i/e
R98LSi/e(ASME)
RC80HPi/e, RC80i/e
RC98HPi/e, RC98i/e
R/C53i(PLUS)
R70e
R75LSi/e, RL75i/e
V53e, RV53e
V53i, RV53i
R50LSi
R63LSe2
1 6 gpm @ 30' head 5 gpm @ 25' head 4 gpm @ 25' head
2 12 gpm @ 30' head 10 gpm @ 25' head 8 gpm @ 25' head
3 18 gpm @ 30' head 15 gpm @ 25' head 12 gpm @ 25' head
4 24 gpm @ 30' head 20 gpm @ 25' head 16 gpm @ 25' head
5 30 gpm @ 30' head 25 gpm @ 25' head 20 gpm @ 25' head
6 36 gpm @ 30' head 30 gpm @ 25' head 24 gpm @ 25' head
7 42 gpm @ 30' head 35 gpm @ 25' head 28 gpm @ 25' head
8 48 gpm @ 30' head 40 gpm @ 25' head 32 gpm @ 25' head
9 54 gpm @ 30' head 45 gpm @ 25' head 36 gpm @ 25' head
10 60 gpm @ 30' head 50 gpm @ 25' head 40 gpm @ 25' head
11 66 gpm @ 30' head 55 gpm @ 25' head 44 gpm @ 25' head
12 72 gpm @ 30' head 60 gpm @ 25' head 48 gpm @ 25' head
13 78 gpm @ 30' head 65 gpm @ 25' head 52 gpm @ 25' head
14 84 gpm @ 30' head 70 gpm @ 25' head 56 gpm @ 25' head
15 90 gpm @ 30' head 75 gpm @ 25' head 60 gpm @ 25' head