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240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
Ver. 1.00
CONFIDENTIAL
The 540 Indoor (T-H3-DV) shares the
computer board with the 540 Outdoor
(T-H3-OS). There are two banks of DIPswitches
(upper and lower bank) on the computer board.
The upper bank has certain special functions
as shown on the following table and generally
should not need adjustment. Carefully verify the
functions of each DIPswitch before changing
any settings.
No.
Functions
ON position
OFF position
1
Gas type
Propane
Disable
2
Natural gas
Disable
3
4
Installation settings
5
N/A
N/A
N/A
(
Default)
6
Deactivation of the exhaust temperature control
(This switch is for a specialized purposes only)
Enable
Disable
(Default)
7
Allow adjustments of fan motor speed
(Changing the FM speed is similar to changing the
manifold pressure. See section 12-15)
Enable
Disable
(Default)
8
Deactivation of the freeze protection firing system
Enable
Disable
(
Default)
The upper bank of DIPswitches
540 (T-H3) models
540 (T-H3) models
computer board
Lower bank of
DIPswitches
Upper bank of
DIPswitches
Outdoor models
No. 3 : OFF
No. 4 : ON
OFF
ON 1 2 3 4 5 6 7 8
Vent settings
(Direct vent Indoor models only)
3" ventings
5 to 20 ft (DEFAULT)
21 to 40 ft
41 to 70 ft
4" ventings
5 to 50 ft (DEFAULT)
51 to 100 ft
N/A
No. 3 : ON
No. 4: OFF
No. 3 : OFF
No. 4 : OFF
No. 3 : ON
No. 4 : ON
Set DIPswitches shown in the table above depending on the vent length.
OFF
ON 1 2 3 4 5 6 7 8
OFF
ON 1 2 3 4 5 6 7 8
OFF
ON 1 2 3 4 5 6 7 8
Set DIPswitches shown
in the table below.
