McQuay TGZ 040A User Manual

OMM TGZ-1 TGZ 040A through TGZ 190A 69
This mode is only operational when the Valve/VFD Control setpoint is set to Valve Stage.
In this mode the valve output is controlled as for Valve Setpoint mode (above), except that
the active setpoint for the controlled parameter is selected according to the following table.
# Of Fans ON Active Setpoint
0 Valve Setpoint
1 Stage #1 ON
2 Stage #2 ON
3 Stage #3 ON
4 Stage #4 ON
VFD Stage, ValveSP/VFDStage, When the Valve/VFD Control setpoint is set to None,
Valve Setpoint, OR Valve Stage, this output is set to 0. Otherwise, it will be controlled in a
manner identical to Valve Stage Mode (above) except that (1) it shall be kept at zero until
the first fan stage is ON, and (2) the following setpoints do not apply.
Valve Control Range (Min)
Valve Control Range (Max)
Valve Type
Valve Type settings are NC (normally closed to tower) or NO (normally open).
These settings establish the operation of a tower bypass valve (must be a 3-way valve).
Initial Valve Position
When the condenser pump is not in the RUN state, the valve output shall be set as a
function of entering condenser water temperature (ECWT) per the following graph.
Figure 9, Initial Valve Position
Max Position @
Setpoint
(90°F)
Min Position @
(60°F)
Min Start Position
(10%)
Initial Valve P
o
s
i
t
i
o
n
(values are exam
p
l
e
s
o
n
l
y
)
M
a
x
S
t
a
r
t
P
o
s
i
t
i
o
n
(
9
0
%
)
Setpoint
Setpoint
Setpoint
Operation After Start
When the condenser pump is in the RUN state, the valve output shall be controlled in one
of two modes as specified by the Valve/VFD Control setpoint. The controlled parameter
shall be the condenser entering water temperature. When the desired output signal varies
from 0 to 100%, the output voltage shall vary as shown below.
0 to 10 VDC (Valve Type = NC)
10 to 0 VDC (Valve Type = NO)
SET TOWER SPs (5)
Valve SP = XXX °
°°
°F
Valve DB = XX.X °
°°
°F

McQuay TGZ 040A Specifications

General

Brand	McQuay
Model	TGZ 040A
Category	Water Heater
Language	English