SDT/SET
Installation & Operation Manual
22
8
Performance Data
Table 8B SDT Backup Recovery Performance
How to Properly Size Your Indirect Water Heater
Use the First Hour Rating (FHR) to properly size your indirect water heater. The FHR is the amount of hot water (in gallons)
that the water heater can supply in the first hour of operation (starting with a tank full of hot water). The FHR is dependent
on tank capacity, source of heat, and the size of the burner.
The indirect water heater and boiler sizing charts can be found on pages 23 and 24. Locate your indirect water heater and boiler
along with your required FHR. This will also determine the flow needed between the indirect water heater and boiler.
Table 8A SET Backup Recovery Performance
Model
Heat Exchanger
Volume
Gallons
Heated
Water
Volume
Gallons
Recovery
Back Up
Minutes
* First Draw
Gallons
Solar
65
°
F
Rise
90
°
F
Rise
115
°
F
140
°
F
SET065
2.2
28
78
108
34
26
SET080
2.2
35
89
123
44
31
SET119
3.2
44
120
166
55
42
Model
Heat Exchanger
Volume
Gallons
Heated
Water
Volume
Gallons
Recovery
Back Up
Minutes
Boiler
Output for
Recovery
BTU/HR
* First Draw
Gallons
Boiler
Solar
65
°
F Rise
90
°
F
Rise
115
°
F
140
°
F
SDT065
1.9
2.2
32
8
13
128,000
42
30
SDT080
1.9
2.2
36
9
15
128,000
49
35
SDT119
2.6
3.2
53
10
17
217,000
65
50
*
Amount of water drawn from tank with no energy input
NOTICE
The charts utilize only the upper boiler
coil and the upper half of the tank.
