Bosch Appliances 125X LP Water Heater User Manual


 
12
Fig. 13 - Electrical wiring diagram
E661_002
WATER IS NOT HOT ENOUGH
1. Temperature selection too low.
Change the setting. Turn the temperature adjustment knob
clockwise (to the right).
Note: This will decrease the activation flow rate.
2. Water flow through the heater is higher than the
capacity of the AquaStar to heat it
Reduce the flow demand at the faucet. See flow rates at
specific temperature rises on page 2.
3. Btu input is too low due to insufficient gas pressure
It is extremely important for a tankless
instantaneous water heater to have the right size
gas line to obtain the correct gas pressure
See specifications on page 2. Unlike storage tank water
heaters, the burners of a tankless water heater must be
very powerful to heat water instantaneously since they do
this only at the time hot water is actually being used. It is
therefore imperative that the gas pressure requirement
be met exactly. Insufficient gas pressure will directly affect
the water temperature at the time of usage. See page 2
for correct gas pressure settings and fig. 14 for locations
where gas pressures are taken.
4. Btu input is too low due to insufficient gas supply
Make sure your main gas line is fully opened. If using LP
gas, be sure that the size of the propane tank is adequate
to supply the required gas pressure.
5. Cold water is mixing with the hot water between
the AquaStar and the outlet
Compare water temperature at outlet of the AquaStar (hold
the AquaStars outlet pipe with your hand) and at the tap.
If these two are very different, check for mixing valve or
plumbing crossover (see NO SPARK AT THE PILOT
paragraph #4). Where automatic anti-scald valves are
required by code, lower the temperature setting on the
AquaStar as much as possible and balance the pressure
between cold and hot water after the AquaStar.
6. Parts in water flow valve are corroded so that the
gas passage is not fully opening.
HOT WATER TEMPERATURE FLUCTUATES / UNIT
DEACTIVATED
1. Unbalanced pressure in waterlines
The added restriction caused by the Aquastar 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 Aquastar burners to shut down (deactivate). Make sure
faucet aerators or shower heads are free of minerals.
Do not add any flow restrictor to the shower head.
Typically this deactivation symptom is a result of the
hot water being too hot to use comfortably. Warm inlet
water generally causes this. Lowering the control
knob setting and/or reducing the inlet gas supply to
the heater should correct this deactivation symptom.
PILOT SPARKS CONTINUOUSLY WITH NO WATER
RUNNING
1. Microswitch needs adjustment
If no water is running, but pilot electrode continuously
sparks, the microswitch screw to the water valve needs
adjustment. See Figure 12.
PILOT LIGHTS BUT BURNERS WILL NOT COME ON
1. Confirm water valve assembly is working properly.
2. Confirm the flame sensor is in its proper position.
3. Confirm the burner electrovalve switch is
functioning properly.
Call CEC
4. The electronic Control Box (Fig. 13) may need to
be replaced.
Call CEC.
114 gas control valve
115 burner electrovalve
116 battery compartment
1.5V D batteries (2)
119 overheat sensor
4 electronic control box
43 pilot electrovalve
51 pilot electrode
52 flame sensor
96 microswitch assembly
99 on/off switch
WATER IS TOO HOT
1. Temperature Selection too high
Turn the temperature adjustment knob counter-clockwise
(to the left) to lower the maximum water temperature.
Note: This will increase the activation flow rate.
2. Inlet water temperature is very warm (60º-75ºF)
Reduce inlet gas supply to lower the heaters degree rise.
Note: Only the Model 125BS should be used if the inlet
water is preheated.