Operating instructions

11
5. Hydronic Circulator Pump Control
The hydronic circulator pump is energized either directly
with the compressor contactor through the internal pump
relay (RP) and 3-pole terminal block (BP) or through an
isolation relay having its 24Vac coil wired to the Y and X
terminals.
6. 4-Way Valve Control
When 24Vac is applied to the O terminal on the wiring
block, the controller energizes its O output to provide
24Vac power to the reversing valve (VR) to switch the
refrigerant circuit to the cooling mode.
7. Compressor Lockouts
The controller will lock out the compressor if either of the
following switches open: 1) high-pressure 600 psig, 2) low-
pressure 35 psig (previously 50) on ground loop or 60 psig
on ground water, or 3) discharge refrigerant temperature
(275ºF). A 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. Low water flow or extreme water temperatures
2. Cold ambient air temperature conditions
3. Internal heat pump operation problems.
If a lockout condition exists, the heat pump should not be
reset more than once; and a service technician should be
called immediately.
CAUTION – Repeated reset may cause severe damage to
the system and may void warranty. The cause of the
lockout
must be determined and corrected.
8. System Diagnostics
The controller is equipped with diagnostic LED lights that
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 mode RED
If a room thermostat installed with the heat pump system
has a lockout indicator, the controller will send a signal
from L on the terminal strip to a LED on the thermostat to
indicate a lockout condition.
9. 24 Vac Fuse
The controller has a glass-cartridge fuse located on the
circuit board adjacent to the 24Vac power connector. The
green system power LED will be off if this fuse is open. A
spare fuse is located in the saddle attached to the side of the
24Vac power connector, and the GW240 and 360 also have
a miniature rocker-type circuit breaker located on the
divider-wall in the electrical box.
Note – Ensure the new
fuse fits tightly in the fuse clips after replacement.
10. Alarm Output
This output is a 2-position screw terminal connector
identified as “Fault Test” on the controller board and as DO
on the wiring diagram. It is an isolated dry contract output
(0.1 ohm resistance) that closes during a controller lockout
and is intended for use as an input to a dial-out type of
monitoring system. The maximum electrical rating is 2mA
up to 30Vac or 50mA up to 40Vdc.
11. GW360 Compressor Overload Modules
The GW360 has additional compressor overload modules
mounted directly onto the compressor.
X. STARTUP / CHECKOUT
Before applying power to the heat pump, check the
following items:
• Water supply plumbing to the heat pump is completed
and operating. Manually open the water valve on well
systems to check flow. Make sure all valves are open
and air has been purged from a loop system.
Never
operate the system without correct water supply flow on
either the ground side or the hydronic side.
• All high voltage and all low voltage wiring is correct
and checked out, including wire sizes, fuses and
breakers. Set system to the “OFF” position.
• Note – the heat pump is located in a warm area
(above 45
o
F). (Starting the system with low ambient
temperature conditions is more difficult and may cause
low-pressure lockout.) Do not leave the area until the
space is brought up to operating temperatures.
• Hydronic side water temperatures are warm enough
(50
o
F or above) to start in the heating mode.
Apply power to the unit. A 4-minute/35-second delay on
power-up is programmed into the controller before the
compressor will operate. During this time, the pump relay
will energize the hydronic side-circulating pump. Verify the
flow rate and temperature of the hydronic side flow.
The following steps will ensure the system is heating and
cooling properly. After the initial time-out period, the red
indicator light on the controller will shut off. The heat
pump is now ready for operation.
• Turn the heating setpoint to its highest temperature
setting, and place the system to run in heating. The
compressor should start 1 to 2 seconds later. If an
electronic thermostat is used, it may cause its own
compressor delay at this time, but the compressor will
come on after the time-out period.
• After 5 minutes of heating operation, check hydronic-
side return and supply water temperatures. A water
temperature rise of 10
o
F to 15
o
F is normal (variation in
water temperature and water flow rate can cause slight
variations). Use a single pressure gauge to check the
fluid pressure drop through the heat exchangers to
ensure proper flow for the system.
• Set the system to the “OFF” position. The compressor
will shut down in 1 to 2 seconds.
• Next, turn the setpoint to its lowest setting. Place the