23
Page
240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
Ver. 1.00
CONFIDENTIAL
10-2. Gas manifold
Part #
• 319143-515 (EK181) : Propane
• 319143-516 (EK182) : Natural gas
Unit Part#
Included
in #102
Function
1. The manifold distributes gas from the gas valves to the burners. The
manifold has two types of the nozzles: one type for gas-rich burners (16
nozzles) and the other for air-rich burners (15 nozzles)
2. There are 3 zones within the manifold, to ensure efficient combustion
operation.
Failure events
1. Dust deposit on the manifold.
2. Gas leakage from a failed manifold.
3. Ignition failure.
4. Imperfect combustion.
Effects on the water heater
if the manifold fails
1. The burners cannot receive proper gas flow from the manifold, which can
cause poor combustion in the combustion chamber. In this case, the AFR
rod will detect an improper flame condition and computer will take safety
measures.
2. Gas leakage from the manifold.
Error codes when
the manifold fails
101 111 121 991
Diagnostic
1. Visual inspection: Excessive dust deposit around the nozzles or cracks on
the manifold.
2. Check voltages and resistance: proper range of values shown below.
Color / Number of wires
Blue - Red
93 to 120 VDC / 2.07 to 2.53 kΩ
Checkpoint
N/A
319143-515 (EK181) for Propane model
and 319143-516 (EK182) for Natural
gas model is an assembly of the gas
manifold with the gas valve assembly.
For safety reasons, these assemblies
should be installed in the unit as a
whole set.
The gas manifold has the “68A” "120V"
mark on the manifold plate.
Nozzles for air-rich burners
Nozzles for gas-rich burners
11V
68A
120V
9-1/8" (232 mm)
"68A"
"120V" mark
"11V" mark
