Operating instructions
16
2. Inlet water temperature is too warm or inlet water
is preheated
Decrease gas pressure. Note: Only the Model 125B S
AquaStar should be used if the inlet water is preheated.
3. Inlet filter screen is clogged, restricting flow
Remove screen and clean it.
WATER IS NOT HOT ENOUGH
1. Temperature selection is set too low.
Change the setting. Turn the temperature selector 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 temperatures on page 2.
3. Gas pressure is insufficient
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 see page 9 for proper gas line sizing.
4. Gas supply is insufficient
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. See gas pipe sizing
chart on page 9.
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.
Contact your service person or Controlled Energy.
HOT WATER TEMPERATURE FLUCTUATES
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. 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 AquaStar 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 30 psi. Confirm that the
pressure tank is not water logged.
4. Gas pressure is too low
See page 2 for correct specifications.
EXHAUST FAN DOES NOT OPERATE
1. Check the fuse (see fig 10)
2. Check all electrical connections
3. Check adjustment of fan microswitch
FAN CIRCULATES WHEN HOT WATER IS SHUT
OFF
1. Check adjustment of fan microswitch