Bosch EP015 Installation And Maintenance Manual page 9

The UPM includes the following features:
• ANTI-SHORT CYCLE TIME—5 minute delay on
break timer to prevent compressor short cycling.
• RANDOM START—Each controller has a unique
random start delay ranging from 270 to 300 seconds to
reduce the chances of multiple units simultaneously
starting after initial power up or after a power
interruption, creating a large electrical spike.
• LOW PRESSURE BYPASS TIMER—If the compressor is
running and the low pressure switch opens, then the
control will keep the compressor on for 120 seconds.
After 2 minutes if the low pressure switch remains
open, the control will shut down the compressor and
enter a soft lockout. The compressor will not be
energized until the low pressure switch closes and the
anti-short cycle time delay expires. If the low pressure
switch opens 2–4 times in 1 hour, the unit will enter a
hard lock out and need to be reset.
• BROWNOUT/SURGE/POWER INTERRUPTION
PROTECTION—The brownout protection in the UPM
board will shut down the compressor if the
incoming power falls below 18 VAC. The compressor
will remain off till the voltage goes above 18 VAC and
the anti short cycle timer (300 seconds) times out.
The unit will not go into a hard lockout.
• MALFUNCTION OUTPUT—Alarm output is Normally
Open (NO) dry contact. If 24 VAC output is needed
R must be wired to the ALR-COM terminal; 24VAC
will be available on the ALR-OUT terminal when the
unit is in alarm condition. If pulse is selected the
alarm output will be pulsed. The fault output will
depend on the dip switch setting for "ALARM". If it
set to "CONST", a constant signal will be produced
to indicate a fault has occurred and the unit
requires inspection to determine the type of fault. If
it is set to "PULSE", a pulse signal is produced and a
fault code is detected by a remote device indicating
the fault. See L.E.D. Fault Indication below for blink
code explanations. The remote device must have a
malfunction detection capability when the UPM
board is set to "PULSE".
• TEST DIP SWITCH—A test dip switch is provided
to reduce all time delay settings to 10 seconds
during troubleshooting or verification of unit
operation. Note that operation of the unit while in
Revised 12-13
Caution
Subject to change without prior notice
test mode can lead to accelerated wear and
premature failure of the unit. The "TEST" switch
must be set back to "NO" for normal operation.
• FREEZE SENSOR—The default setting for the
freeze limit trip is 30°F (sensor number 1);
however this can be changed to 15°F by cutting
the R30 resistor located on top of the DIP switch
SW1. The default setting for the freeze limit trip is
30°F (sensor number 1); however this can be
changed to 15°F by cutting the R24 resistor
located on top of the DIP switch SW1. Since freeze
sensor 2 is dedicated to monitor the evaporator
coil it is recommended to leave the factory default
setting on the board. The UPM controller will
constantly monitor the refrigerant temperature
with the sensor mounted close to the condensing
water coil between the thermal expansion valve
and water coil. If temperature drops below or
remains at the freeze limit trip for 30 seconds, the
controller will shut the compressor down and
enter into a soft lockout condition. Both the status
LED and the Alarm contact will be active. The LED
will flash (three (3) times) the code associated
with this alarm condition. If this alarm occurs 2
times (or 4 if Dip switch is set to 4) within an hour
the UPM controller will enter into a hard lockout
condition. It will constantly monitor the refrigerant
temperature with the sensor mounted close to the
evaporator between the thermal expansion valve
and evaporator coil . If temperature drops below
or remains at the freeze limit trip for 30 seconds,
the controller will shut the compressor down and
enter into a soft lockout condition. Both the status
LED and the Alarm contact will be active. The LED
will flash (six (6) times) the code associated with
this alarm condition. If this alarm occurs 2 times
(or 4 if Dip switch is set to 4) within an hour the
controller will enter into a hard lockout condition.
If unit is employing a fresh water system (no
anti-freeze protection), it is extremely important to
have the "Freeze" jumper R42 resistor set to 30°F
in order to shut down the unit at the appropriate
leaving water temperature and protect your heat
pump from freezing if a freeze sensor is included.
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EP Series
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