P-K Storm
TM
Gas Fired Boiler
Technical Service 1.877.728.5351
Revised: June 26, 2020
Released: June 26, 2020
©
Patterson-Kelley 2020
All Rights Reserved.
2691000273 P-K Storm ST2500-ST4000
Installation and Owners Manual Rev A.docx
Page 91
The chart below represents the pressure drop (Ft of Head) versus the water flow rate (GPM) for the P-K
STORM ST-2500 through ST-4000. This information is useful to help size an appropriate circulation
pump. Keep in mind this pressure drop represents the boiler only, additional consideration is needed
for any connecting piping, valves, strainers, couplings, flanges, etc.
P-K STORM
™
ST-2500 through ST-4000 Boilers: Minimum & Maximum Flow Rates
Flow
Condition
Boiler
Operation
Flow Rate
Approximate
ΔT
ST-2500
ST-3000
ST-3500
ST-4000
Maximum Flow High Fire
242.5 GPM
291 GPM
339.5 GPM
388 GPM
20 °F
Minimum Flow
High Fire
69.3 GPM
(Flow
Switch
Setting)
83.1 GPM
(Flow
Switch
Setting)
97 GPM
(Flow
Switch
Setting)
110.9 GPM
(Flow
Switch
Setting)
60 °F
Minimum Flow
Ignition
Minimum Flow
Low Fire
MAX FLOW ST-3000
@20°F
Δ
T
291GPM @ 24.3ft
MAX FLOW ST-2500
@20°F
Δ
T
242.5GPM @ 16.9ft
MAX FLOW ST-3500
@20°F
Δ
T
339.5GPM @ 19.6ft
MAX FLOW ST-4000
@20°F
Δ
T
388GPM @ 25.6ft
0
5
10
15
20
25
30
0
20
40
60
80
100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400
Pr
e
ssur
e
Dr
o
p
(Ft.
H
e
ad
)
Flow Rate (GPM)
P-K STORM ST-2500 - ST-4000
Pressure Drop vs. Flow