W
W
W
W
WARNIN
ARNIN
ARNIN
ARNIN
ARNING
G
G
G
G
LP & N
LP & N
LP & N
LP & N
LP & NG ARE EXTREMEL
G ARE EXTREMEL
G ARE EXTREMEL
G ARE EXTREMEL
G ARE EXTREMELY FL
Y FL
Y FL
Y FL
Y FLAMMABLE SO
AMMABLE SO
AMMABLE SO
AMMABLE SO
AMMABLE SO
TTTTTAKE EXTRA PRECA
AKE EXTRA PRECA
AKE EXTRA PRECA
AKE EXTRA PRECA
AKE EXTRA PRECAUTIONS WHEN
UTIONS WHEN
UTIONS WHEN
UTIONS WHEN
UTIONS WHEN
PERF
PERF
PERF
PERF
PERFORMIN
ORMIN
ORMIN
ORMIN
ORMIN G ANY W
G ANY W
G ANY W
G ANY W
G ANY WORK T
ORK T
ORK T
ORK T
ORK TO THE HEA
O THE HEA
O THE HEA
O THE HEA
O THE HEATER
TER
TER
TER
TER
CT-27
page 1 of 1
rev 10/06
Bosch Water Heating
340 Mad River Park, Waitsfield, VT 05673
©
BBT
NORTH AMERICA CORPORATION
Bosch Group
REPLACING CONTROL BOX
MODELS:
1600H, 425HN
Tools
Philips head screwdriver, needle-nosed pliers.
Removing Ignition Unit
1. Close installer supplied cold water isolation valve to
water heater.
2. Remove front cover of heater as per instructions in
the installation manual.
3. Remove single ignition wire connection (to spark
electrode) from upper left corner of ignition unit.
Unclip wire from bracket on top of ignition unit
(425HN models only). (See Fig. 1)
4. Remove multiple wire connector from lower right
corner of ignition unit by gently pulling outwards
with needle-nosed pliers. (See Fig. 1)
5. Remove screw with ground wire connection from
upper right corner of ignition unit. Metal bracket
and ignition unit will drop down out of heater.
6. Remove ignition unit from metal bracket.
Installing Ignition
1. Insert tab on lower left of ignition unit into slot in
lower left of bracket.
2. Mount ignition unit with bracket to heater by insert-
ing screw into upper right hand corner. N
N
N
N
No
oo
oottttteeeee: feed
screw through ground wire eyelet with washer
before threading through ignition unit to heater. (See
Fig. 1)
3. Press multiple wire connector into lower right of
ignition unit.
4. Push ignition wire into single terminal in top left
corner of ignition unit. Clip wire into bracket on top
of ignition unit (425HN models only).
5. Install front cover, open cold water supply and return
heater to service.
1600H, 425HN control box location
FIGURE 1
Control box