Circulator Sizing - Lochinvar Crest 2.5 Installation & Operation Manual

5
Hydronic piping

Circulator sizing

The Crest heat exchanger does have a pressure drop, which must be considered in your system design. Refer to the graph in
FIG. 5-1 for pressure drop through the Crest heat exchanger.
Figure 5-1 Pressure Drop vs. Flow
16
FBN1500
15
14 FBN2000
13 FBN2500
12
FBN3000
11
FBN3500
10
9
8
7
6
5
4
3
2
1
0
0
Table 5A Sizing Information for Temperature Rise Applications_20°F, 40°F and 60°F
BOILER
Model
CONNECTION SIZE
FB 1500 4"
FB 2000 4"
FB 2500 4"
FB 3000 4"
FB 3500 4"
The pressure drop reflected in FIG. 5-1 is
NOTICE
for the boiler only. Additional allowances
must be made for piping, especially if
sizing pumps for Primary/Secondary
applications.
(continued)
CREST Pressure Drop Curve
50 100
Flow Rate (GPM)
TEMPERATURE RISE APPLICATIONS
20°F
GPM FT/HD
138 3.4
184 4.1
230 4.6
277 5.6
323 7.5
[Based on 92% AHRI Effi ciency]
150 200
40°F
GPM FT/HD
69 1.5
92 1.6
115 1.3
138 1.2
161 1.2
It is required that boiler piping systems
NOTICE
utilize Primary/Secondary or Fixed or
Variable Flow Primary configurations as
shown in FIG.'s 5-2 thru 5-5. The use of
other boiler piping configurations could
result in improper building and system flow
rates leading to inadvertent boiler high limit
shutdowns and poor system performance.
Installation & Operation Manual
250 300
60°F
GPM FT/HD
46
61
77
92
108
350
1.0
1.0
0.7
0.7
0.7
25