Bosch AquaStar 125HX LP Installation And Operating Instructions Manual page 16

HOT WATER TEMPERATURE FLUCTUATES / UNIT
DEACTIVATED
1. Unbalanced pressure in waterlines
The added restriction caused by the 125 HX 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 125
HX 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. Temperature balance valves
If the inlet water temperature to the water heater is very
warm the heater can produce temperatures that may be
found to be too hot. A temperature balance shower valve
can automatically mix in cold water to reduce such hot water
temperature, in the event of any temperature instability with
the use of a temperature balance shower valve, refer to
shower valve manufactures instructions for internal
adjustment setting. Adjustments should be made to the
hottest setting in the shower valve. Additionally the
temperature control of the heater can be adjusted to produce
a more comfortable hot water temperature. See SETTING
THE WATER TEMPERATURE section.
3. Cold water is mixing with the hot water between the
125 HX and the outlet
See #2 under "NO SPARK AT THE PILOT".
4. Inlet water pressure is erratic due to inadequate supply
water pressure or saturated pressure tank on well
system
Check the inlet water pressure. For installation on a private
well system with the use of a pressure tank, the lowest
pressure range setting recommended is 30-50 psi (2.07 -
3.45 bar). Confirm that the pressure tank is not water logged.
5. Gas pressure is too low
See page 3 for correct specifications.
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