A.O. Smith T-H3-DV Service Manual

25 Page
240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
Ver. 1.00
CONFIDENTIAL
10-4. Gas valve assembly
Part#
• 319143-515 (EK181) : Propane
• 319143-516 (EK182) : Natural gas
Unit Part#
Included in
#102
Function
Opens and closes the gas pathways of the water heater (main and solenoid
gas valves)
Modulates the gas flow from the gas inlet (proportional gas valve)
Failure events
1. Gas leak from the valves.
2. Unable to open/close (main and solenoid gas valves)
3. Unable to modulate the gas flow (proportional gas valve)
Effects on the water heater
if valves fails
1. Gas leak from the assembly.
2. Excess carbon monoxide emissions. / No flames.
3. Lack of water temperature control.
Error codes when
the fvalves fails
101 111 121 991
Diagnostic
1. Visual inspection: connection/breakage of wires.
2. Listen for "clunk" sounds from the gas valves opening right after fan
motor initiates.
3. Check voltages and resistance of coils; proper range of values shown
below.
Color / Number of wires
Blue - Light blue (MV)
93 to 120 VDC (during operation) /
1.35 to 1.65 kΩ
Check
point
C
Blue - Green (SV
1
)
93 to 120 VDC (during operation) /
1.35 to 1.65 kΩ
Blue - Orange (SV
2
)
93 to 120 VDC (during operation) /
1.35 to 1.65 kΩ
Blue - Red (SV
3
)
93 to 120 VDC (during operation) /
2.07 to 2.53 kΩ
White - Red
(Proportional valve)
1.0 to 15 VDC (during operation) /
20 to 40 Ω
319143-515 (EK181) for Propane model and 319143-516
(EK182) for Natural gas model is an assembly of the gas
manifold with gas valve assembly. For safety reasons,
these assemblies should be installed in the unit as a whole
set. The diagram below shows the gas valve assembly.
Proportional Valve
2-3/4" (70 mm)
3-3/4" (93 mm)
4-3/8" (112 mm)
1-3/4" (46 mm)
5-1/4" (134 mm)
Gas valve
Propornal valve
Solenoid valave
Main gas valave
4-1/2" (112.8 mm)

A.O. Smith T-H3-DV Specifications

General

Brand	A.O. Smith
Model	T-H3-DV
Category	Water Heater
Language	English