12/06/2012 45
GI202
Troubleshooting – GEO Logic Control
Sensor Temperature Calibration
– all four remote sensors are digital electronic and factory calibrated.
Normally these do not require field calibration or verification. However, if sensor temperature error is
determined, use special PC software and PC USB port cable. The PC screen has direct readout of the four
monitored temperatures, it allows a visual determination of temperature settings, and can be used to offset the
temperature sensors for troubleshooting and demonstration purposes.
NOTE
Temperature Sensors
Temperature sensors installed in TTHERM GEO heat pumps
are NOT thermisters
. They are digital devices
calibrated at the manufacturer. They are polarity sensitive. Be sure to connect the red and white wires in their
correct shared terminals. The black wire is the data stream wire and will have its own screw terminal.
Bad sensor, safety
– if the internal logic detects open sensor wire, a shorted sensor wires, or an incorrectly
wired sensor; the green POWER LED reverts to a pulsing mode.
Bad sensor, operating default condition
– the detection of bad sensor forces the controller to a fixed stage
operation. Software declared bad sensor default – ST = 70° F, LWT (heating) = 32°F, LWT (cooling) = 77° F,
CDT = 200° F, DDT = 190° F.
Check the GEO Logic Controller section of this manual for in depth description of the diagnostic information
available by observing the LED’s.
Internal fuses –
the source loop, hydronic loop pumps, and desuperheater pump are fused on the high voltage
pump relay board.
The pump hookup decal provides the fuse size and details.
Troubleshooting/Repair Helps
1.
This GEO Logic controller contains several interference suppression components, but as an electronic
logic product, unpredictable and unusual transients or interferences may sometimes cause strange
results. If the GEO Logic controller is “acting strange”, one immediate step would be power down
reset. Simply turn off the 240 volt source power. When the green POWER LED goes out, count to 10,
and re-energize power supply.
2.
The terminal blocks for control wire hook-up are designed for a wire insertion and screw clamp down.
If there is no wire connected and the screw is loose, the screw may not necessarily make a good
electrical contact to the inside components. Example – if you jumper the thermostat terminals without
thermostat wire connection or if you are attempting to measure voltage on the screw head, you may get
erroneous or unpredictable results if the screw is not tightened down.
3.
Use general heating/heat pump system logic information and basic understanding of the terminal block
wiring functions when measuring voltage to determine proper operation.
Open/Closed Loop Operation –
TTHERM GEO heat pumps are factory set for open loop operation. Open/Closed
loop operation is set with
Jumper J 11
on the left side of the GEO Logic controller. The jumper must be in place
on J11 if the unit is operated on an open loop. The GEO Logic controller protects the heat exchanger from freezing
by causing the compressor to shut down when the leaving water temperature reaches 38° F open loop and 20° F
closed loop. The compressor will remain off for 2 ACD’s, and the EARTH LOOP FLOW/ SOURCE WATER
LIMIT & HP STAGE 1 LED’s will pulse, while the water runs and warms up. The compressor will then restart
again providing heat until the LWT again reaches 38° F open loop and 20° F closed loop. If this routine continues
the heat pump will not be able to maintain the temperature in the house and the backup heat will come on.
Possible causes would include:
Open
Loop
Closed
Loop
1. Supply water filter that needs cleaning
1. Inadequate source water flow
2. Inadequate source water flow
2. Antifreeze protection inadequate
3. Water discharge line that is plugging up
3. Heat exchanger needs to be cleaned
4. Entering water temperature less than 50 degrees
5.
Heat exchanger needs to be cleaned
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