37
110332-04 - 2/23
PHTM II
Installation, Operating & Service Instructions
Boiler Model
Boiler Supply
Connection
inch, FPT
Boiler Return
Connection
inch, FPT
ΔT = 35°F
ΔT = 30°F
ΔT = 25°F
ΔT = 20°F
Minimum
Required
Flow
(GPM)
Boiler
Head
Loss,
(ft.)
Minimum
Required
Flow
(GPM)
Boiler
Head
Loss,
(ft.)
Minimum
Required
Flow (GPM)
Boiler
Head
Loss,
(ft.)
Minimum
Required
Flow
(GPM)
Boiler
Head
Loss,
(ft.)
PHTM2080HB
1
1
4.3
7.2
5.0
9.5
6.0
13.1
7.5
19.8
PHTM2120H
PHTM2120HB
1
1
6.4
11.2
7.5
14.6
9.0
20.0
11.2
29.7
PHTM2150H
1
1
8.1
8.2
9.4
10.9
11.3
15.3
14.1
23.4
PHTM2180H
1
1
9.7
11.6
11.3
15.5
13.5
21.8
16.9
33.5
Notes:
1. Required Flow (GPM) = **Output (MBH) x 1,000/(500 x ΔT)
**Output (MBH) - select value for specific boiler model from Table 3-1. Using boiler antifreeze will result in higher pressure drop
and may require larger circulators.
2. Boiler head loss includes 50 eq. ft. near boiler piping. [Approximately 20 ft. straight pipe, (4) 90° elbows and (2) full port ball
valves]
Table 10-1: Head Loss at Selected Flow Rates
10
Heating System Piping
(continued)
Figure 10-2: System Curve w/ 50 Equivalent ft. of Piping
