Temperature Rise And Heat Exchanger Head Loss - PEERLESS PUREFIRE PFC-2500 Installation, Operation & Maintenance Manual

IX. HYDRONIC PIPING (CONTINUED)
D. Temperature Rise and Heat Exchanger Head Loss
1. The PFC heat exchanger adds pressure drop to the system which must be accounted for in the design of the
piping configuration and pump selection.
2. For systems with glycol mixture, the flow rate specified in Table 21 will increase as specified in Table 25 due
to the extra frictional loss introduced by the glycol. Size pump accordingly.
3. Strictly follow glycol manufacturer's guidelines and recommendations when adding glycol in the heating system.
4. The system should be designed to maintain the recommended water flow rate shown in Table 21 while never
exceeding the range of absolute flow rates shown in Table 24. Exceeding the maximum water flow rates can
cause pipe erosion, damage the flow switch, and allow unsafe operation.
a. Maintaining sufficient flow through the boiler will help prevent the buildup of scale.
Table 21: Temperature rise, flow rate, and head loss
Recommended Range
Delta 20 °F Delta 25 °F
PFC
Head
Boiler
GPM Loss GPM
Model
(ft)
2000 194 19.7 155
2500 242 15.4 194
3000 291 20 232
3500 339 14.4 271
4000 388 18.1 310
Required Flow = Output×1000/(500×ΔT), where flow rate is in GPM, output is in MBH, and ΔT is in 0F, Outputs are
shown in Table 1.
This Boiler has a temperature rise limit of 55 °F
20
16.7
13.35
10
6.7
3.35
38
Delta 30 °F
Head Head
Loss GPM Loss
(ft) (ft)
13.9 129 10.5
11.3 161 8.9
14.6 194 11.3
10.0 226 7.6
12.4 258 9.3
0 50 100
Figure 13: Heat exchanger water pressure loss
Delta 35 °F Delta 40 °F
Head Head
GPM Loss GPM Loss
(ft) (ft)
111 8.2 97 6.7
138 7.2 121 6.1
166 9.2 145 7.7
194 6.1 170 5.2
221 7.4 194 6.1
150 200 250
Water Flow Rate (gal/min)
Delta 45 °F Delta 50 °F
Head Head
GPM Loss GPM Loss
(ft) (ft)
86 5.6 80 4.7
107 5.2 97 4.6
129 6.6 116 5.8
150 4.5 135 4.0
172 5.3 155 4.7
1250 MBtu/h
1500 MBtu/h
2000 MBtu/h
3000 MBtu/h
4000 MBtu/h
300 350 400
PFC2000-4000 Boiler I,O&M Manual Rev. 2
Delta 55 °F
Head
GPM Loss
(ft)
71 4.1
88 4.0
105 5.1
123 3.7
141 4.2