AV30 PRE-INSTALLATION REQUIREMENTS | AV30 Pre-Installati on Requirements | v. 3.0
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b (n) LP
Compressor
(circuit number)
Low pressure
Low
temperature, loss
of refrigerant
Auto/ Manual
Delayed
b (n) AC
Compressor
(circuit number)
freeze alarm
Low
temperature,
Low Flow
Auto/ Manual
Delayed
b1tF
Fan thermal
alarm
Fan jammed (ice) Manual
Instantaneously
C(n) tr
Compressor
(circuit number)
thermal alarm
Running at high
temperatures
Manual
Instantaneously
AEht
Evaporator inlet
high
temperature
High water
temperature
Manual
Instantaneously
b1AC Set Point
After the unit is primed, you need to lower the freeze point of the reservoir.
**Note: Contact MTA
to determine the PG ratio before adjusting the freeze alarm (b1AC) from set
point of 40F.
This will be based on the climate extremes for your chillerʼs location. For standard ambient
temperature above (32F) set the (b1AC) to 25F
To Lower freeze point follow the instructions below.
TURN UNIT TO STNBY TO ACCESS
Verify that the glycol percentage in the circulated coolant is adequate to protect the coolant from
freezing at the target outlet temperature. You must use Glycol and NOT water. Also consider the
minimum ambient air temperature if the chiller is to be installed outdoors. Adjust the glycol
percentage for the lowest of these temperatures with at a 10F safety factor below the freeze
alarm set point. For example, to operate at 25F coolant outlet temperature (indoors) set the
freeze alarm set point at 15F and adjust the glycol percentage to a minimum of 30% (by volume)
to provide freeze protection to 5F.
1. Change the freeze alarm set point as follows:
2. Enter the programming mode of the controller by holding the
“set” & “down arrow” buttons
down simultaneously until the
“Pr1” prompt (amber) appears with the “PASS” entry above it
(red).
3. Press the
“set” button once and the upper display (red) will show a flashing “0”. Use the “up
arrow
” to change the flashing “0” to the user password value (“23”). If the password is correct,
the upper display (red) will show
“ALL”.
4. At the
“ALL” prompt press the “down arrow” once to display the “AL” menu. Then press “set”
once to display the AL26 parameter (amber). This is the freeze alarm set point. The factory value
is 39
˚F (5˚C) and will be displayed above the parameter label in red.
5. Press the
“set” button once and the upper display (red) will start flashing. Use the “down
arrow
” to adjust the parameter to the appropriate value commensurate with the glycol protection
temperature.
6. Press the
“set” button once more to store the new value.
