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338
FORM 160.54-M1
ISSUE DATE: 10/25/2019
SECTION 36 - SOFTWARE ENHANCEMENTS
JCI COMPANY CONFIDENTIAL
JOHNSON CONTROLS
CHILLER MOD –
COMPRESSOR
PROXIMITY
SENSE
OIL
HEATER
OUTPUT*
LEVEL
CONTROL
PERIOD
DEFAULT
FLOW SWITCH
OIL-VARIABLE SPEED
PUMP PRESSURE SETPOINT
NOT ACHIEVED
THRESHOLD*
Mod C, D, E –
G, H, J Compr
Probe
TB1-34
3.5 sec
Paddle Type
35 psid
Mod E – P Compr
Limit Switch
TB1-64
10.0 sec
Paddle Type
25 psid
Mod F – G, H
Compr
Limit Switch
TB1-64
3.5 sec
Factory Mounted
Thermal Type
35 psid
Mod F – J Compr
Probe
TB1-64
3.5 sec
Factory Mounted
Thermal Type
35 psid
Mod F – P, Q
Compr
Limit Switch
TB1-64
10.0 sec
Factory mounted
Thermal Type
25 psid
* Not applicable to Mod C (and earlier) chillers.
SI0034 - SOFTWARE ENHANCEMENTS EFFECTIVE AUGUST 2002 (CONT'D)
FACTORY MOUNTED FLOW SENSORS
Style F (and later) chillers are supplied with factory-
mounted flow sensors on the evaporator and condens-
er. These are electronic thermal-type sensors. The op-
erating principle of the sensor is thermal conductivity.
It uses the cooling effect of a flowing liquid to sense
flow. The temperature of the heated sensor tip is sensed
by a thermistor located in the tip.
A second thermistor, located higher in the tip in a non-
heated area, is only affected by changes in liquid tem-
perature. The temperatures sensed by the thermistors
are compared. Flowing liquid carries heat away from
the heated sensor tip, lowering its temperature. The
lower temperature differential between the two therm-
istors indicates the liquid is flowing. A higher differen-
tial indicates no flow. Each device operates from a 24
VAC power source and has a solid state relay output.
On each sensor, one side of the solid state relay output
(pin 2) is connected to the micr5 VDC and the
other side (pin 4) is connected to a Microboard Analog
Input.
When flow is sensed, the solid state relay output is
turned on causing it to conduct current through the
7.5K ohm microboard load resistor to the +5 VDC.
This applies more than +4 VDC to the microboard in-
put (evaporator J7-14; condenser J7-16). When no flow
is sensed, the solid state relay output is turned off, re-
sulting in no conduction through the load resistor. This
applies less than 1 VDC to the microboard input. To
determine the state of the solid state relay, first confirm
that +5 VDC is present at pin 2 of the flow sensor. Then
connect a voltmeter from Microboard J7-14 (evapora-
tor) or J7-16 (condenser) to Microboard TP1 (ground).
The power source is connected to the sensor as follows:
From
To
Sensor pin 1 TB1-162 (24 VAC)
pin 3
TB6-5 (GND)
The sensor outputs are connected to the microboard as
follows:
Evaporator:
From
To
Sensor pin 2 Microboard J7-1 (+5 VDC)
pin 4
J7-14 (input to Microboard )
Condenser:
From
To
Sensor pin 2 Microboard J7-15 (+5 VDC)
pin 4
J7-16 (input to Microboard)