F. potable expansion tank, G. pressure drop sizing for circulator – HTP SuperStor Ultra Indirect Fired Water Heaters User Manual
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LP-83 Rev. 3.24.14
This water heater can deliver scalding water. Be careful
whenever using hot water to avoid scalding injury.
Certain appliances, such as dishwashers and automatic
clothes washers may require increased water
temperature. By setting the thermostat on this heater to
obtain the increased water temperature required by
these appliances, you may create the potential for scald
injury.
To protect against injury, you should install a mixing
valve in the water system. This valve will reduce point of
discharge temperature by mixing cold and hot water in branch supply lines. Such valves are available from your local plumbing supplier.
Table 6 details the relationship of water temperature and time with regard to scald injury and may be used as a guide in determining the
safest water temperature for your applications.
F. POTABLE EXPANSION TANK
A potable hot water expansion tank may be required to offset heated water expansion. If there is a back flow preventer or any other
type of no return or check valve on the system, a thermal expansion tank is mandatory. The expansion tank must be sized for the entire
water volume of the hot water system. A weeping relief valve indicates the need for an expansion tank. See Typical Expansion Tank
installation, Fig. 4, for more details.
G. PRESSURE DROP SIZING FOR CIRCULATOR
The boiler circulator flow rate must meet the requirements found in Figure 1 or the published ratings cannot be achieved. The flow chart
below represents the pipe run, water heater, and heat exchanger ONLY and does not include any flow checks, zone valves, or friction
loss through the boiler. That resistance must be added to the value found in the chart below.
PRESSURE DROP FOR PIPE
LENGTH OF 1” COPPER, SIX 90
o
ELBOWS, AND ONE TEE
PIPE SIZE
20’
30’
40’
50’
60’
6 GPM
8.63
8.93
9.23
9.53
9.8
7 GPM
11.3
11.77
12.24
12.7
13.1
10 GPM
10.25
11.1
11.95
12.8
13.66
12 GPM
11.3
13.2
14.1
15
16
14 GPM
15.3
16.4
17.5
18.6
19.8
14 GPM
15.3
16.4
17.5
18.6
19.8
PRESSURE DROP FOR PIPE LENGTH OF 1 ¼” COPPER, TEN 90
o
ELBOWS, AND TWO TEES
PIPE SIZE
20’
30’
40’
50’
60’
20 GPM
10.9
11.7
12.6
13.4
14.3
22 GPM
14
15
16
17
18
24 GPM
16.2
17.5
18.8
20.1
21.5
28 GPM
20.4
22
23.6
25.2
26.8
Table 7
APPROXIMATE TIME / TEMPERATURE RELATIONSHIPS IN SCALDS
120
o
F
More than 5 minutes
125
o
F
1 ½ to 2 minutes
130
o
F
About 30 seconds
135
o
F
About 10 seconds
140
o
F
Less than 5 seconds
145
o
F
Less than 3 seconds
150
o
F
About 1 ½ seconds
155
o
F
About 1 second
Table 6