Mammoth HP-5 Microprocessor Control User Manual
Page 3
MAMM‐WHSP‐IOM‐1HP5A (October 2011)
3
FAN OPERATION:
On a call for fan operation
from the wall thermostat “fan on" switch or from
a call for compressor operation, fan operation is
delayed for 2 seconds.
REVERSING VALVE:
On a call for cooling from
the wall thermostat, the reversing valve is
energized after 4 seconds. Once the cooling
demand is satisfied, the reversing valve is held
on for 4 seconds before it is de-energized.
COMPRESSOR OPERATION:
On a call for
cooling or heating from the wall thermostat,
the compressor is energized from the
compressor output terminal after 6 seconds.
Once the call for cooling or heating is satisfied,
the compressor shuts off immediately. At that
time, a 300 second (5 minute) timer begins to
prevent the compressor from re-starting even
though the wall thermostat may again call for
cooling or heating. During this 300 second
interval, the compressor will not be allowed to
restart. After the 300 second time delay elapses,
the compressor is allowed to start if the wall
thermostat calls for cooling or heating.
FAN INTERLOCK OPERATION:
When
compressor operation is required, the fan is
automatically enabled 4 seconds before the
compressor, even if the wall thermostat is not
calling for fan operation. This makes sure the
fan will be on whenever the compressor is on.
SAFETY CIRCUIT OPERATION:
The unit has
up to 4 safety circuits to prevent the compressor
from operating during abnormal conditions.
High Pressure Switch: If the refrigerant
pressure exceeds the high pressure set-
point, the high pressure switch opens
immediately and the unit goes into the
lockout mode
Low Pressure Switch: If the refrigerant
pressure falls below the low pressure set-
point, the low pressure switch closes
immediately and the unit goes into the
lockout mode after the amount of low
pressure bypass has been satisfied.
Optional Freezestat Switch: If the leaving
fluid temperature falls to 32°F, the freezestat
switch opens. After 10 seconds, the unit
goes into lockout mode.
Condensate Overflow Protection: If the
drain pan sensor comes in contact with
moisture for more than 30 seconds, the unit
goes into lockout mode.
LED STATUS
:
ON
Normal operating mode
1 Flash
High pressure fault
2 Flashes
Emergency shutdown mode
3 Flashes
Freezestat switch
4 Flashes
Condensate overflow fault
5 Flashes
Low voltage fault
6 Flashes
High voltage fault
7 Flashes
Low pressure fault
LOCKOUT MODE:
Lockout mode will occur if
any of the safety circuits are activated. In this
condition the compressor is de-energized, but
the fan operates if the wall thermostat is calling
for cooling or heating. The two lockout alarm
circuits are also enabled.
LOW AND HIGH VOLTAGE PROTECTION:
If
voltage conditions are good, the unit performs a
self-diagnostic check for faults. If no faults are
identified, the “green” LED comes on with no
flashes. If the supply voltage falls below the
minimum or above the maximum, the reversing
valve, fan and compressor are de-energized.
LED lights will indicate the fault. Once the
voltage falls within an acceptable range, the unit
will restart without requiring a reset. All time
delays required for start-up of the fan,
compressor and reversing valve will take place
before the unit is re-started. The low voltage cut-
out is 21.6 VAC and the cut-in is 24.0 VAC. The
high voltage cut-out is 34.0 VAC and the cut-in
is 29.7 VAC. These high and low voltages are
monitored at terminals “R” and “COM”.
LOCKOUT ALARM (CIRCUIT) SIGNAL
: This is
the first lockout alarm circuit. In the lockout
mode, the circuit provides a 24-volt power (+)
signal at the “LO ALM” terminal of the terminal
block which is wired to the LED on the wall
thermostat to indicate a lockout condition.
DRY CONTACTS LOCKOUT ALARM
(CIRCUIT) SIGNAL:
This is the second lockout
alarm circuit. In the lockout mode, this circuit
provides a signal at the terminal block. The
signal is a set of normally open contacts at
terminals "IN ALM" and "OUT ALM" of the unit
terminal strip. The contacts close in the lockout
mode, allowing connection of a remote alarm.
RESET OF A LOCKOUT:
The controller can be
selected to manual or intelligent reset of a
lockout mode through an on-board dip switch
labeled as “RST”. When a manual reset is
selected, the unit stays in lockout until it is