Johnson Controls TM9V MP UIM-B-0509, Diagnostic Fault Code Storage And Retrieval

438335-UIM-B-0509

DIAGNOSTIC FAULT CODE STORAGE AND RETRIEVAL

The control in this furnace is equipped with memory that will store up to five error codes to allow a service technician to diagnose problems more easily. This memory will be retained even if power to the furnace is lost. This feature should only be used by a qualified service tech- nician.

If more than five error codes have occurred since the last reset, only the five most recent will be retained. The furnace control board has a but- ton, labeled LAST ERROR that is used to retrieve error codes. This function will only work if there are no active thermostat signals. So any call for heating, cooling or continuous fan must be terminated before attempting to retrieve error codes.

To retrieve the error codes, push the LAST ERROR button. The LED on the control will then flash the error codes that are in memory, starting with the most recent. There will be a two-second pause between each flash code. After the error codes have all been displayed, the LED will resume the normal slow green flash after a five second pause. To repeat the series of error codes, push the button again.

If there are no error codes in memory, the LED will flash two green flashes. To clear the memory, push the LAST ERROR button and hold it for more than five seconds. The LED will flash three green flashes when the memory has been cleared, then will resume the normal slow green flash after a five-second pause.

(Seconds)

Thermostat Calling for Heat

Thermostat Satisfied

0 2

17

22

52

0

Fan on Delay

30 Seconds

THERMOSTAT

OFF

ON

OFF

INDUCER

ON

OFF

15

OFF

ON

Sec.

Post

IGNITOR

OFF

OFF

Purge

OFF

MAIN VALVE

ON

OFF

OFF

HUMIDIFIER

OFF

ON

OFF

OFF

ELECTRONIC

ON

AIR CLEANER

OFF

OFF

OFF

CIRCULATING

ON

BLOWER

OFF

OFF

60, 90, 120, 180 SEC.

OFF

Selectable Fan Off Delay

FIGURE 42: Furnace Control Event Schedule

Johnson Controls Unitary Products 35