Mammoth 800 to 5500 CFM: Dedicated Outdoor Air System with Enthalpy Wheels (VHC) - Manual (Page 45)

MAMM-VHC-IOM-1A (JANUARY 2013) 45
Water Valve Piping Arrangement
It is important to follow the proper piping arrangement for
both two-way and three-way water valves. Incorrect piping
arrangements will damage the unit. The field piping sche-
matic is illustrated below.
For Two-way Valve
Two-way valves should be installed in accordance to the
arrow direction marked on the valve body for the water inlet
or supply line. Two-way valves should be installed with the
disc upstream. If installed with disc downstream, flow curve
will be deeper. If installed “backwards” it is not necessary to
remove and change. No damage or control problems will
occur.
For Three-way Valve
Three-way valves must be installed with the ‘AB’ marked
or common port to the supply water line, the ‘A’ marked
or control port to the coil and the ‘B’ marked, ‘Bypass’ or
middle port to the return water line.
Correct Piping
Incorrect Piping
Valve and Actuator Installation
Mount the valve directly in the pipe where the assembly will
not block the system vent or other components. Do not grip
the actuator while making and tightening up plumbing con-
nections. Either hold valve body in your hand or attach ad-
justable wrench across the hexagonal or flat faces on the
valve body. If assembling valve train on bench, take care
not to deform the body with a vise.
Refrigerant components
P P P
Access valve Access valves
Scroll compressor
Switch high
pressure
Crank case heater
Switch low optional
pressure valve kit
Pressure
transducer
Pressure transducer factory
mounted at compressor
discharge port
Unit water inlet
Field mounted
Head pressure
control valve
option
On/off valve
accessory
Strainer Modulating
three-way valve Motorized valve
water shut-off
Water inlet
H B
Flow
switch
option Water inlet
Unit water outlet
A
T
C B
J K
Figure K8: Water valve piping arrangement
AB A A AB
A AB 0% AB 100%
Two-way valves
should be installed
with the disc
upstream.
Flow direction
A AB Belimo
A
Figure K9: Two-way valve arrangement
Diverting
A AB
B
A AB
B
A
B A
B AB 100% AB 0%
AB 70%
AB 0%
The A-port must
be piped to the coil
to maintain proper
control.
Figure K10: Three-way valve arrangement
1 input, 2 outputs
Coil
Return
Supply
B
A AB
Figure K11: Correct three-way diverting valve piping
1 input, 2 outputs
Coil
Return
Supply
B
A
AB
Figure K12: Incorrect three-way diverting valve piping
Figure K13: Valve installation
CAUTION
If the valve is piped incorrectly, it must be re-piped as it
may restrict flow and cause damage to the unit.