Specifications

13
LP-83 Rev. 8.14.14
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