Freeze protection – Mammoth 800 to 5500 CFM: Dedicated Outdoor Air System with Enthalpy Wheels (VHC) User Manual
Page 40
MAMM-VHC-IOM-1A (JANUARY 2013)
40
NEMA 4x rated actuator must be installed. The hydronic
valves are intended for use in a normal indoor/outdoor en-
vironment for hot or cold water or glycol solutions to 60%
concentration with a medium temperature rating of 0°F to
212°F [−18°C to 100°C]. The actuator must be field wired
to the standard field wiring (FW) terminals #435, 436 and
437 depending on valve size. The valve and actuator are
preassembled for 0% flow to the coil when the unit does
not require heating or cooling.
See Table K3 for two-way valve sizing, performance data
and dimensions; installation and technical data is included
with accessory parts. See the wiring schematic for connec-
tion information.
Freeze Protection
A water flow switch and a temperature sensor as an op-
tion and mounted on the water return or leaving side of the
condenser are used to monitor the presence or absence
of flow and the water temperature which will shut down
the compressor and unit for freeze protection. The flow
switch also features an adjustment which allows the user
to change the switch from normally open (NO) to normally
closed (NC).
The temperature sensor is factory mounted and wired in-
ternally. The flow switch must be externally field mounted
in the leaving or return water line and field wired to the
standard field wiring (FW) terminal strip as per wiring sche-
matic. See performance, dimensions and installation data
at the end of this appendix.
Table K2: Three-way Valve Sizing and Performance Data
Tons
Minimum US
GPM
Condenser Pressure
Drop (PSI)
Condenser
Maximum
Pressure (PSI)
Three-way Head Pressure Control Valve
C
v
Maximum Pressure
(PSI)*
Size FPT
2
6
4.3
400
3.0
600
½
3
9
9.2
400
3.0
600
½
4
12
3.0
400
4.7
600
¾
5
15
5.0
400
7.4
600
¾
6
18
7.0
400
7.4
600
1
8
24
7.7
400
7.4
600
1
10
30
4.3
400
10.0
400
1¼
12
36
7.0
100
19.0
400
1¼
14
42
6.0
400
19.0
400
1¼
*Maximum close off pressure 200 psi.
Table K3: Two-way Valve Sizing and Performance Data
Tons
Minimum US
GPM
Condenser Pressure
Drop (PSI)
Condenser
Maximum
Pressure (PSI)
Two-way Water Shut-off Valve
C
v
Maximum Pressure
(PSI)*
Size FPT
2
6
4.3
400
24
600
¾
3
9
9.2
400
24
600
¾
4
12
3.0
400
24
600
¾
5
15
5.0
400
24
600
¾
6
18
7.0
400
19
400
1¼
8
24
7.7
400
19
400
1¼
10
30
4.3
400
19
400
1¼
12
36
7.0
100
37
400
1½
*Maximum close off pressure 200 psi.