17
3. Burners are not shutting down immedi-
ately when hot water is turned off
If burners don't shut off
immediately when hot
water is turned off, the heater will overheat and
the ECO will shut off the gas. Replace both
parts in the water valve assembly (part #38475,
33071). (See Letter R, Fig 2, page 6).
WATER IS TOO HOT
1. Temperature setting is too high
Unlike storage tank heaters which need to be
set at a higher temperature than is needed in
order to stretch the volume of hot water by mix-
ing in cold water, an AquaStar can be set for the
exact temperature needed and give endless hot
water without need for mixing in cold water. We
recommend setting the temperature selector dial
on #4 or #5. For more information, see section
on Setting Water Temperature, Page 12.
2. Thermostat is not functioning properly
(See #1 under PILOT LIGHT GOES OUT DUR-
ING OR AFTER HOT WATER USE)
WATER IS NOT HOT ENOUGH
1. Temperature dial is set too low
Change the setting.
2. Water flow through the heater is higher than
the capacity of the AquaStar to heat it
If the AquaStar flow restrictor has been removed,
the flow through the heater might be higher than
its capacity to heat it. Reduce the flow to a range
2. Gas pressure too low
Very low gas pressure may be caused by low
delivered gas pressure, by a jammed gas regu-
lator or by undersized gas lines. If the gas lines
are undersized, there may still be the specified
static gas line pressure. However, when the
water valve opens, the pressure will drop
sharply, causing the pilot flame to go out. Have
a gas service person confirm the gas pres-
sure both statically and at maximum Btu input.
Specifications for your heater are on page 3.
within which the heater can maintain tempera-
ture. See flow chart on Page 18. AquaStar
water heaters have a (removable) flow restrictor
to assure that the maximum volume flowing
through the heater remains in the range that the
heater can heat to a suitable temperature,
regardless of how many faucets are being used.
This is to ensure that the flow is never higher
than what the heater can heat to a suitable
temperature. The AquaStar model 170 flow
restrictor is set for a maximum of 4 1/4 gallons
per minute. Note: In private well installations,
the high and low cycling control of your water
pump may be set too low or the pressure tank
may be water logged.
3. BTU input is too low due to insufficient
gas pressure
It is extremely important for a tankless wa-
ter heater to have the right size gas line to
obtain the correct gas pressure.
See specifications for correct gas pressures on
page 3. 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 actu-
ally being used. It is
imperative that the gas
pressure requirement be met exactly. Insuffi-
cient gas pressure will directly affect the water
temperature. Static gas pressure in the line
can be measured at the pressure test nipple
located on the AquaStar manual shut-off valve
(Letter L, Fig 2, Page 6). Manifold pressure
may be tested at the manifold pressure test
nipple (Letter G).
4. BTU input is too low due to insufficient
gas supply
Make sure your main gas line is fully opened.
If using LP gas, minimum size of the propane
tank should be 100 pounds for best results.
5. Cold water is mixing with the hot water
between the AquaStar and the outlet
Check for possible automatic mixing valve in
the line or a plumbing crossover (see #6 - MAIN
BURNERS DO NOT IGNITE WHEN HOT
WATER IS ON).
