Bosch WR 400-7.K Series Installation & Operation Manual page 12

6. Parts in water flow valve are corroded so that the
gas valve is not fully opening.
Contact your service person or call:
Canada 1-800-663-8405, U.S.A 1-800-824-7337.
HOT WATER TEMPERATURE FLUCTUATES
1. Unbalanced pressure in waterlines.
The added restriction caused by the Bosch in the hot water
system can result in uneven pressures between the cold and
the hot. In such cases when mixing cold water at the tap, the
lower hot water pressure may be overpowered by a much
higher cold water pressure, which may cause the Bosch
burners to shut down. Make sure faucet aerators or shower
heads are free of minerals. Do not add any flow restrictor
to the shower head.
2. Cold water is mixing with the hot water between the
Bosch and the outlet.
See # 4 under "NO SPARK AT THE PILOT".
3. Inlet water pressure is erratic due to inadequate
supply water pressure or saturated pressure tank on well
system.
Check the inlet water pressure. On a private well, raise
minimum pressure setting to 40 psi. Confirm that the pressure
tank is not water logged.
4. Gas pressure is too low.
See page 8 for correct specifications.
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