Bosch GWH 260 PN Service Bulletin Booklet page 20

REPLACING ELECTRO VALVES
MODELS: 1600H, 425HN
Tools
Philips head screwdriver
Pliers
8mm or adjustable wrenc h.
Preparation
This procedure should be performed by a
licensed gas technician
Before at tempting to replace either electro valve,
turn off gas supply to the water heater and turn ON
(I) /OFF (O) switch to the OFF (O) position.
Removing Electrovalve
1. Locate the pilot and burner electro valves on the
lower front of the water heater just to the left of the
temper ature control knob and water val ve (See
Fig.1).
2. Determine which electro valve is going to be re-
placed. The upper electro valve (orange) is r espon-
sible for the pilot and the lower electro val ve (green)
is responsible for the burners.
3. Using pliers, disconnect wire at spade connection on
electro valve needing replacement.
4. Remove the two Philips head screws on each side of
the Electrovalve.
5. Remove the electro valve from the gas valve housing.
Be careful not to misplace the rubber o-ring that
seals the electro valve to the gas valve. If a new o-
ring is provided with new electro val ve, discard the
original o-ring. N N N N N O O O O O TE: TE: TE: TE: If removing the pilot electro TE:
valve, remove the pilot orif ice from the top of the
electro valve by unscrewing the 8mm orifice nut with
appropriate wrench (See Fig. 1). Do not lose the
pilot orif ice.
©BBT NORTH AMERICA CORPORATION
Bosch Group
W W W W W ARNIN ARNIN ARNIN ARNING G G G G
ARNIN
LP & N LP & N G ARE EXTREMEL G ARE EXTREMEL
LP & N LP & NG ARE EXTREMEL LP & N G ARE EXTREMEL G ARE EXTREMELY FL
T T T T T AKE EXTRA PRECA AKE EXTRA PRECA AKE EXTRA PRECA AKE EXTRA PRECAUTIONS WHEN
AKE EXTRA PRECA
PERFORMIN PERF PERF ORMIN G ANY W ORMIN ORMIN G ANY WORK T G ANY W G ANY W
PERF PERF ORMIN G ANY W
Installing electro valve
1. If installing the pilot electro valve, insert and tighten
the pilot orifice nut from the old valve into the top of
the new pilot Electrovalve.
2. Inser t the rubber o-ring into the groove of the electro
valve housing on the gas valve. Failure to do this may
result in a gas leak.
3. Insert electro valve into the electro valve housing on
the gas valve making sure to align the screw holes
between the two.
4. Reconnect wire fr om the electronic control box to
the electro v alve.
5. Turn on the gas supply to the water heater and chekc
for ga s leaks.
6. Return the heater to ser vice. If the unit does not
ignite at first, try cycling the water off and on to
make sure that air has been sufficiently bled from
the gas line. N N N N N o o o o o t t t t t e e e e e : It may take several cycling at-
tempts to purge all the air out.
FIGURE 1
Pilot electro valve
340 Mad River Park, Waitsfield, VT 05673
Y FL Y FL AMMABLE SO AMMABLE SO
Y FL Y FLAMMABLE SO AMMABLE SO AMMABLE SO
UTIONS WHEN UTIONS WHEN UTIONS WHEN
UTIONS WHEN
ORK T ORK T ORK TO THE HEA O THE HEATER O THE HEA O THE HEA TER TER TER
ORK T O THE HEA TER
Burner electro valve
Bosch Water Heating
CT-26
page 1 of 1
rev 10/06