15
Table H: Heater Rates of Flow and Pressure Drops
Notes: Basis for minimum flow is ∆T . Basis for maximum flow is gpm.
Model
No.
20°F ∆T
30°F ∆T
35°F ∆T
Min. Flow
Max. Flow
gpm ∆P (ft) gpm ∆P (ft) gpm ∆P (ft) gpm ∆P (ft)
∆T
gpm ∆P (ft) ∆T
H7-300A
28
17
19
8
16
6
14
5
39
36
28
16
H7-400A
38
18
25
7
21
5
19
4
39
47
29
16
H7-500A
47
16
31
7
27
5
24
4
39
56
23
17
H7-700A
66
30
44
13
38
9
34
7
39
70
34
19
H7-850A
80
40
53
17
46
12
41
10
39
80
40
20
may be exposed to circulating refrigerated air, must be
equipped with flow control valves or other automatic
means to prevent gravity circulation of the heater
water during the cooling cycle. It is highly recommend-
ed that the piping be insulated.
Air-Separation/Expansion Tank
All heaters should be equipped with a properly-sized
expansion tank and air separator fitting as shown in
Fig. 6 above.
System Sensor Installation
The System Sensor (S3) is required for all selectable
mode unless the unit’s firing rate will be controlled by
an external source such as the Temp Tracker MOD+
Hybrid sequencer (sales option B-36). Proper place-
ment and method of installation are critical for proper
operation of the system. (See Fig. 7) The sensor must
be installed in a drywell in conjunction with heat con-
ductive compound as shown in the following images.
The drywell must be installed no more than 5 equiva-
lent feet of pipe/tubing downstream of the de-coupler
and installed in such a way that ensures the sensor
bulb is in the flow path.
Fig. 6: Air-Separation/Expansion Tank
Three-Way Valves
Three-way valves intended to regulate system water
temperatures by reducing flow in the boiler should not
be used. Raypak heaters are high-recovery, low-mass
heaters which are not subject to thermal shock.
Applications & Modes
The VERSA IC Control system is designed for a wide
range of applications. The installer/design engineer
should refer to the following Modes to determine which
best fits the intended application and functionality for
the unit being installed.
CAUTION:
Be careful when installing the drywell
not to over-tighten the well as this can damage the
well and may prevent the sensor from fitting
property.
Fig. 7: System Sensor Installation
NPT
Fitting
Drywell
Thermal
Paste
System
Sensor (S3)
