OMM TGZ-1 TGZ 040A through TGZ 190A 39
Suction Superheat
Suction superheat is calculated for each circuit using the following equation:
Suction superheat = Suction Temperature – Evaporator Saturated Temperature
Pumpdown Pressure
The pressure to which a circuit will pump down is based on the Low Evaporator Pressure
Unload set point. The equation is as follows:
Pumpdown pressure = Low evap pressure unload – 15 psi
The low limit for the calculated Pumpdown Pressure set point is 10.0 psi
Unit Enable
The Unit Enable Set Point controls enabling and disabling the unit. The Unit Enable Set
Point has options of OFF and ON. The Unit OFF input, Remote input, keypad entry, and
BAS request can alter this set point. The Control Source Set Point determines which
sources can change the Unit Enable Set Point with options of SWITCHES, KEYPAD or
NETWORK.
Changing the Unit Enable Set Point can be accomplished according to the following table.
NOTE: An “x” indicates that the value is ignored.
Unit Off
Input
Control Source
Set Point
Remote
Input
Key-
pad Entry
BAS
Request
Unit
Enable
OFF X x x x OFF
x SWITCHES OFF x x OFF
ON SWITCHES ON x x ON
ON KEYPAD x OFF x OFF
ON KEYPAD x ON x ON
ON NETWORK x x OFF OFF
ON NETWORK OFF x x OFF
ON NETWORK ON x ON ON
Unit Mode
The overall operating mode of the chiller is set by the Unit Mode Set Point with options of
COOL, COOL w/Glycol, ICE w/Glycol, and TEST. This set point can be altered by the
keypad, BAS, and Mode input. Changes to the Unit Mode Set Point are controlled by two
additional set points.
Available Modes Set Point: Determines the operational modes available at any time with
options of COOL, COOL w/Glycol, COOL/ICE w/Glycol, ICE w/Glycol and TEST
Control Source Set Point: Determines the source that can change the Unit Mode Set Point
with options of KEYPAD, NETWORK, or SWITCHES.
When the Control source is set to KEYPAD, the Unit Mode shall stay at its previous setting
until changed by the operator. When the Control source is set to BAS, the most recent BAS
mode request shall go into effect even if it changed while the Control source was set to
KEYPAD or DIGITAL INPUTS.
To Next Page
Loading...
Need help?
General