Operating instructions

10
The anticipator has the effect of reducing system capacity
by restricting run time.
The thermostat should never be set back to less than 60
o
F.
Air temperatures less than 60
o
F to the heat pump in
residential applications can cause difficult starting
conditions and lock the unit out. Commercial
applications can be designed to use lower entering air
temperatures, but 60
o
F is a safe low operating point in
residential applications.
C. Controller
The controller receives a signal from the thermostat and
initiates the correct sequence of operation for the heat
pump. The controller performs the following functions:
1) Blower Operation
2) Earth Loop Pump Initiation
3) Compressor Operation
4) 4-Way Valve Control
5) Compressor Lockouts
6) Compressor Anti-Short-Cycle
7) System Diagnostics
8) Overflow Detection
1. Blower Operation
A signal on the G terminal from the thermostat to the
controller will tell the controller to energize the blower.
The controller then energizes its G output to send control
voltage directly to the blower motor relay.
To change blower speeds, move the wire on the fan
terminal strip to the desired setting. Changing the speed
from the factory setting can cause problems with output
air temperature or reduced airflow, locking out the unit.
2. Earth Loop Pump Initiation
If a PumpPAK is used, it should be wired directly to the
contactor of the compressor. If a PumpPAK is not used,
a separate pump can be used which is energized with a
pump relay (Note: electrical code will require a fused
disconnect for pumps other than PumpPAKs). When
there is a call for an M1 output from the controller, the
contactor will energize, starting the compressor and earth
loop pump.
3. Compressor Operation
A Y1 signal from the thermostat will ask the controller to
initiate heating or cooling. The controller then decides,
based on lockout and anti-short-cycle periods, when to
bring the compressor on. The M1 output of the controller
energizes the compressor. This compressor stays on until
on the thermostat is satisfied.
4. 4-Way Valve Control
The controller energizes the 4-way reversing valve to
direct the flow of refrigerant. When the thermostat calls
for cooling on the O terminal, the controller energizes its
O output to send control power to the reversing valve
(VR) to switch the refrigerant circuit to the cooling mode.
5. Compressor Lockouts
A compressor lockout occurs if the high-pressure, low
pressure (in heating mode), or freeze protection pressure
switches open. The controller blocks the signal from the
thermostat to the contactor that normally would energize
the compressor. In the event of a compressor lockout the
controller will send a signal from L on the terminal strip
to an LED on the thermostat to indicate a lockout
condition. This lockout condition means that the unit has
shut itself down to protect itself, and will not come back
on until power has been disconnected (via the circuit
breaker) to the heat pump for one minute. Problems that
could cause a lockout situation include:
1. Water flow or temperature problems
2. Air flow or temperature problems
3. Internal heat pump operation problems
4. Cold ambient air temperature conditions
(( If a lockout condition exists, the heat pump should not
be reset more than once; a service technician should be
called immediately. II The cause of the lockout must be
determined. Repeated reset may cause damage to the
system.
6. Compressor Anti-Short-Cycle
An anti-short-cycle is a delay period between the time a
compressor shuts down and when it is allowed to come on
again. This protects the compressor and avoids nuisance
lockout conditions. Anti-short-cycles occur after these
three conditions;
1. A 30 second to one minute time-out period occurs
on the compressor before it will start after its last
shutdown.
2. A four minute 35 second delay is incorporated into
the timing function immediately after power is
applied to the heat pump. This occurs only after
reapplying power to the unit. To avoid this
timeout while servicing the unit, apply power,
disconnect and reapply power very quickly. This
can sometimes eliminate the waiting period.
3. A four-minute anti-short-cycle will occur after a
low-pressure switch opens in the cooling mode.
This is done to eliminate nuisance lockout
conditions. If the compressor continuously short
cycles in the cooling mode, shut the thermostat off
and call your service technician.
7. System Diagnostics
The controller is equipped with diagnostic LED lights
which indicate the system status at any particular time.
The lights indicate the following conditions:
1. 24 Volt system power GREEN
2. Fault or Lockout YELLOW
3. Anti-short-cycle mo de RED
8. Overflow Detection
An optional overflow detection sensor may be added to
the GeoSource 2000 heat pumps. This sensor is located
in the drain pan, and monitors the amount of water
accumulated in the pan. If the condensate drain becomes