Trane LO manual Reading the Operating Machine State, Terminal Unit Control TUC

Terminal Unit

Control (TUC)

Table 40. Blink Sequence Corresponding Diagnostic Codes

Sequence 1	Sequence 2	Sequence 3
1 2 3 4	1 2 3 4	1 2 3 4	Code	Diagnostic	Latch
			None	Power failure	None
			None	Controller failure	None
ϒ ϒ ϒ ϒ	ϒ ϒ ϒ ϒ	ϒ ϒ ϒ ϒ	00	None	N/A
ϒ ϒ ϒ ϒ	λ ϒ ϒ ϒ	λ ϒ λ λ	8B	Condensate overflow	Yes
ϒ ϒ ϒ ϒ	λ ϒ ϒ λ	λ ϒ λ λ	9B	Leaving water temp	No
				sensor 1 failure
ϒ ϒ ϒ ϒ	λ ϒ λ ϒ	ϒ ϒ ϒ ϒ	A0	Zone and supply temp	No
				sensor failure
ϒ ϒ ϒ ϒ	λ λ ϒ ϒ	λ ϒ ϒ ϒ	C8	High EWT	No
ϒ ϒ ϒ ϒ	λ λ ϒ ϒ	λ ϒ λ λ	CB	Low EWT	No
ϒ ϒ ϒ ϒ	λ λ ϒ ϒ	λ λ λ λ	CF	Low temp. detect. or	Yes
				condensate overflow
ϒ ϒ ϒ ϒ	λ λ ϒ λ	ϒ ϒ λ λ	D3	Low discharge air temp	Yes
ϒ ϒ ϒ ϒ	λ λ ϒ λ	ϒ λ ϒ ϒ	D4	Smoke alarm	Yes/No
ϒ ϒ ϒ ϒ	λ λ ϒ λ	ϒ λ ϒ λ	D5	High dischg air temp	Yes/No
ϒ ϒ ϒ ϒ	λ λ ϒ λ	λ λ ϒ λ	DD	Low fresh air temp	No
ϒ ϒ ϒ ϒ	λ λ λ λ	λ ϒ ϒ ϒ	F8	Bad configuration	No
ϒ ϒ ϒ ϒ	λ λ λ λ	λ λ λ ϒ	FE	Return air high limit	Yes

Reading the

Operating

Machine State

Use the human interface to read the unit operating machine state.

1.Read and record the initial TUC address.

2.Set the TUC DIP switch #5 and #8 to ON (address = 9). The remaining switches will be off.

3.Short and hold the test input.

4.The LEDs will blink to define an operating machine state. The operating machine state information will be displayed in a series of three blink sequences.

Sequence 1: When the test input is shorted continuously all LEDs go off for one second.

Sequence 2: LED #5 will light to indicate that sequence 2 is currently being displayed. LEDs one through four will display the first part of the operating machine state.

Sequence 3: LED #6 will light to indicate that sequence 3 is currently being displayed. LEDs one through four will display the second part of the operating machine state.

5.Reference Table 25 on page 75 to interpret the operating machine state derived from the blink sequences.

102 UNT-IOM-6