Carrier GZ024 Installation Instructions Manual

Carrier GZ024 Installation Instructions Manual Manual pdf 32 page image

32Service ToolA B C NO USE COND C W1 Y1 Y2 0A150782Fig. 25 -- Service Tool ConnectionWhen working on the outdoor unit of a split system, the technicianwould usually need to repeatedly walk between the indoor wallcontrol and the unit outside. To save time, the communicatingcontrols offer a service tool feature.By wiring the service tool into the UPM board, the technician canhave a wall control capable of running the system right at theoutdoor unit.To use a service tool, connect the A and B communication buswires from this second communicating control to the terminalsmarked A and B on the terminal strip located in the bottom leftcorner of the UPM board (see Fig. 25). But instead of connectingthe wires on the service tool to the terminals marked C and D,connect the C and D wires from the service tool to the 24V and Con ST1 as shown in Fig. 25.When the service tool is connected and powered up, thecommunicating controls inside the home will ”go to sleep” and letthe service tool take control of the system. In this manner, theservice technician can run the diagnostic checkouts right at theoutdoor unit using the service tool.After the checkouts are completed and it is no longer necessary touse the service tool, remove it from the communicating controlsand the indoor communicating controls will regain control in abouttwo minutes.HRP TroubleshootingThe HR pump will be enabled when compressor dischargetemperature is 120_F (48.9_C) or above.The circulating pump will be disabled if water temperature reaches140_F (60_C) or amperage exceeds 0.4 amps.HRP TroubleshootingProblem Possible Cause Checks and CorrectionsNO FLOWLOW FLOWNo Power Check power supplyOn/Off Switch Position Set switch to “ON” positionCompressor Contactor Engage heat pump contactorBroken or loose wires Repair or tighten wiresAir Lock Purge air from piping systemStuck pump shaft/impeller Remove pump cartridge and cleanDefective pump Replace pumpKinked or under sized water piping Repair kink and check for proper line sizeHIGH WATERTEMPERATURE Water temp limit closed Stuck limit switchSensor not attached securely to lineLOW HEAT OUTPUT Clean heat exchangerScaled or fouled heat exchanger

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