Takagi T-H3-DV Service Handbook

TROUBLESHOOTING
TROUBLESHOOTING
24 • On-Demand Water Heater Service Handbook for 240, 340 & 540 Condensing Models
The 540 Indoor (T-H3-DV) model uses the same computer board
as the 540 Outdoor (T-H3-OS) model. There are two banks of DIP
switches (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.
Verify the functions of each DIP switch carefully before changing
any settings. If you have questions, contact the technical service
department.
Table 6: 540 (T-H3) model
Upper bank of DIP switches (Figure 10)
NOTE: Dark squares represents DIP switches
Lower bank of
DIP switches
Upper bank of
DI
P switches
Figure 10 : 540 (T-H3) Model

No. Funcons ON posion OFF posion
1 Gas type Propane Disable
2 Natural gas Disable
3
4
Installaon sengs
5 N/A (Do not change switch posion.) N/A N/A
(Default)
6* Deacvaon of the exhaust temperature control
(This switch is for a specialized purpose only)
Enable Disable
(Default)
7 N/A (Do not change switch posion.) N/A N/A
(Default)
8 Deacvaon of the freeze protecon firing system Enable Disable
(Default)
Outdoor models
No. 3 : OFF
No. 4 : ON
OFF
ON
1 2 3 4 5 6 7 8
Vent sengs (Indoor model only)
3" venngs
5 to 20  (DEFAULT) 21 to 40  41 to 70 
4" venngs
5 to 50  (DEFAULT) 51 to 100  N/A
No. 3 : ON
No. 4: OFF
No. 3 : OFF
No. 4 : OFF
No. 3 : ON
No. 4 : ON
Set DIP switches 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 DIP switches shown
in the table below.
Propane
OFF
ON
1 2 3 4 5 6 7 8
Natural
Gas
OFF
ON
1 2 3 4 5 6 7 8
WARNING:
Do not adjust DIP switch No. 6 without guidance from the technical service department. The
only me DIP switch 6 should be set to ON is when your unit is being hooked up to CAT III/IV metal vent
with a maximum temp. rang of 480° F. The No. 6 DIP switch deacvates the exhaust temperature control
when set to the ON posion.
Failure to follow this warning can lead to personal injury, carbon monoxide poisoning, or death.
*
Continued on the next page.

Takagi T-H3-DV Specifications

General

Brand	Takagi
Model	T-H3-DV
Category	Water Heater
Language	English