A.O. Smith T-D2-OS User Manual

T-D2-IN / T-D2-OS Service Manual
Ver. 1.00
18
CONFIDENTIAL
10-2. Gas manifold
Unit Part #
Included
in #102
Takagi Part #
EKH6T (LP model)
EKK5K (NA model)
Checkpoint
N/A
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
78 to 100 VDC / 0.9 to 1.7 kΩ
Nozzles for gas-rich burners
Nozzles for air-rich burners
9-1/8" (232mm)
6-7/8" (175mm)
46V
59J
"46V" mark (LP)
"59J" mark (NA)
EKH6T (for LP model) and
EKK5K (for NA 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 for the LP
has the “46V” mark, and
the gas manifold for the NA
has the “59J” mark on the
manifold plate.

A.O. Smith T-D2-OS Specifications

General

Brand	A.O. Smith
Model	T-D2-OS
Category	Water Heater
Language	English