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Maintenance and service
17
5 Maintenance and service
5.1 Maintenance intervals
The GWH 1600 PS requires periodic maintenance.
The below time maintenance intervals should keep the
unit operating for many years.
Every year
BInspect inlet water filter screen ( 5.2)
BInspect pilot assembly and flame ( 5.3)
BInspect burner assembly ( 5.4)
BInspect vent system for blockage
Every 2 years
BLubricate and clean water valve ( 5.2)
Every 3 to 5 years
BRebuild water valve ( 5.2)
BClean pilot assembly and clean or replace orifice
(5.3)
5.2 Water valve
The water valve is the main control that tells the heater
to fire. If the periodic maintenance is neglected, more
costly damage may occur over time.
Inspecting inlet water filter screen
Shut off the installer supplied cold water isolation valve
to the heater. If one is not installed, install before
proceeding. Open the nearest hot water tap to drain the
plumbing lines. Position a bucket under the heater's
water valve assembly to catch any water that may drain
from the heater. Remove cold water supply connection
on rear right-hand side of water valve. Inlet filter is
recessed inside water valve. Carefully pry filter screen
out with a blunt object. Clean with water and inspect for
damage. If the filter is at all damaged, it should be
replaced.
Lubricating the water valve
A more detailed instruction is available on our website
at www.boschhotwater.com. Shut off the installer
supplied cold water isolation valve to the heater. If one
is not installed, install before proceeding. Open the
nearest hot water tap to drain the plumbing lines.
Position a bucket under the heater's water valve
assembly to catch any water that may drain from the
heater. Remove water pipes connected to the back of
the water valve. Remove heat exchanger piping
connected to the right and left side of water valve.
Loosen the two set screws (Fig. 27, num. 36) at the top
of the water valve where it connects to the gas valve. If
the set screws are seized, STOP and call Bosch tech
support before proceeding. Forcing and snapping
seized set screws may cause irrevocable damage to the
water valve and gas valve assemblies. Remove the
water valve from the heater by pulling it down. Once
free from the heater, separate the two halves of the
water valve by removing the three screws on the top of
the water valve. Apply lithium or faucet & valve grease to
the pushrod and o-ring. (See Fig. 25, num. 27). With
needle-nosed pliers, remove recessed venturi tube from
right hand port on water valve (Fig 27, num. 32). Inpect
venturi and clean if necessary. If plugged with mineral
deposits, soak in straight vinegar for at least one hour
prior to cleaning.
Rebuilding the water valve
Several parts within the water valve should be replaced
every 3 to 5 years depending on water quality and
usage. The parts list and instructions can be found on
our website at www.boschhotwater.com. Failure to
rebuild the water valve can result in decreased
performance or damage to the heater.
Warning: Failure to perform
recommended maintenance may result
in complete failure of the unit over time.
The warranty does not cover failures
due to improper or insufficient
maintenance.