60
3. Check the resistance across the cad cell pins with the cell covered (protected from exposure to
ambient light). The resistance should be greater than 20,000 ohms.
4. If cell resistances are different from above, replace the plug-in portion of cell, (Honeywell Part No.
130367).
5. Carefully reinsert the plug-in portion of the cad cell into the receptacle. If the cad cell appears to be
functioning correctly, troubleshoot the fan control module and the safety and ignition control (primary
control) module, according to the Honeywell instructions covering the devices.
The troubleshooting chart beginning on the following page should help identify the type of malfunction or
deviation from normal operation. To use this diagram, just follow the instructions in the boxes. If the
answer is yes or the condition is true, go down to the next box. If the answer is no or the condition is
false, go to the box on the right. Continue checking and answering questions and conditions in each box
until a problem and/or repair is found. After any maintenance or repair, the trouble shooting sequence
should be repeated until normal system operation is achieved.
Summary of Contents for OH6FA072D48N
Page 5: ...2...
Page 33: ...30 Heating Speed Set ups 2 Stage OH6FX072DV4 Figure 18 2 ECM 2 stage blower motor speed chart...
Page 64: ...61 VIII Sequence of Operations Flow Chart...
Page 65: ...62...
Page 66: ...63 IX Trouble Shooting Flow Chart...
Page 67: ...64...
Page 68: ...65...
Page 69: ...66...
Page 70: ...67...
Page 72: ...69 Appendix A Replacement Parts Replacement Parts for OH6FA072D...
Page 73: ...70 Replacement Parts for OH8FA119D...
Page 74: ...71 Appendix B Wiring Diagrams OH6FA072D48 PSC Wiring Diagram...
Page 75: ...72 OH6FA072DV4 ECM Wiring Diagram...
Page 76: ...73 OH6FX072DV4 ECM 2 Stage Wiring Diagram...
Page 77: ...74 OH8FA1119D60 PSC Wiring Diagram...
Page 78: ...75 OH8FA1119DV5 ECM Wiring Diagram...
Page 79: ...76...