Water Connections - Bosch GWH 345 ESR-N Manual

Installation instructions
3.9 Checking restrictor plate size by
measuring CO
B Remove brass flat head screw on the exhaust collar.
Fig. 31 Measuring port
B Insert CO
analyzer probe into the measuring point.
2
The tip of the probe should be in the center of the flue
pipe. Avoid air gaps between probe and measuring
port to avoid inaccurate readings.
B Press On/Off button to turn heater On.
For this test the unit has to be put in Service Level.
B Open a hot water tap.
B After 10 seconds, press and hold the reset button
.
B Rotate the recirculating water temperature selector
(left knob) to the minimum and then to maximum.
B Release the reset button and the display should
show * (blinking).
B Rotate the hot water temperature selector
maximum.
B The restrictor size is correct if the CO
the values as per table 14.
CO2 value (%)
enter here: ___________________
Table 13
Appliance
GWH-345-ESR-N
GWH-345-ESR-L
GWH-450-ESR-N
GWH-450-ESR-L
Table 14 CO levels at max. input
2
B If the CO
content is too high, use the next largest
2
restrictor.
B After replacing the restrictor, measure CO
again. Repeat procedure until correct level is
obtained.
26
level value.
2
6720607909-32.3JS
to the
level is within
2
CO (%)
2
6.8 - 7.2
7.5 - 8.0
6.5 - 7.0
7.0 - 7.5
level
2
B Once correct reading is obtained, replace screw with
gasket in exhaust collar.
B Press On/Off button to turn heater Off and exit
Diagnostic Mode.

3.10 Water connections

B When facing the heater, the ¾" NPT inlet is on the
bottom right and the ¾" NPT outlet is on the bottom
left (Fig. 32). Install the heater centrally in the build-
ing if possible and make piping runs as short as pos-
sible.
OUTLET INLET
Fig. 32
B The use of unions when connecting both water pipes
to the inlet and outlet connections is recommended.
This will facilitate any necessary servicing.
B Although water piping throughout the building may
be other than copper, we recommend that copper or
suitably rated stainless steel flex line piping be used
for the water connections for 3' on either side of the
recirculating water heater (follow local codes if more
stringent).
B Never sweat any rigid piping directly to or beneath
the water connections, damage can occur to the
internal heater components during the sweating
process.
B Plastics or other PEX type plumbing line materials
are not suitable for connecting directly to the water
heater.
B Keep water inlet and outlet pipes to no less than ¾"
(19.05mm) diameter to allow the full flow capacity.
B If the cold and hot connections to the heater are
reversed, the heater will not function correctly. Be
certain there are no loose particles or dirt in the
piping. Blow out or flush the lines before connecting
to the water heater.
B Full port shut off valves should be installed on both
the cold water supply and hot water outlet lines to
facilitate servicing the heater (see Fig. 33).
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