A.O. Smith AWH-35, Инструкция по эксплуатации, Страница: 23 / 48

START UP
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flow is decreased the temperature rise will increase and as
water flow is increased the temperature rise will decrease.
Because of this relationship between temperature rise and
flow rate this test can be useful to determine if the flow rate
through the heat exchanger is adequate. Other factors may
also affect water flow rate and temperature rise such as
debris or lime scale build up inside heat exchanger or water
pump operation .
If the temperature rise through the HPWH is consistently
lower than 8°F the outlet (supply) valve can be throttled
slightly closed to reduce the water flow rate. This may be
necessary on installations with a minimum of water piping
between the HPWH and the water system or tank.
Throttling should be done in small increments, no more than
1/8 turn of the valve handle at a time. The HPWH must run
be allowed to run for approximately 5 minutes between each
adjustment before the temperature rise is measured again.
If the outlet valve is throttled during start up, mark the valve
position and remove the valve handle to ensure it is not
accidentally changed.
If the temperature rise through the HPWH is consistently
greater than 12°F the water flow may be restricted. Ensure
all water valves between the HPWH and the tank or water
system are fully open. Ensure the water pump inside the
HPWH is running. If the temperature rise continues to be
excessive call the toll free technical support phone number
on the back cover of this manual for further assistance.
5 . Using thermometers or temperature sensors, measure the
temperature of the return (inlet) air to the HPWH and the
supply (outlet) air leaving the unit. The outlet air temperature
should be 12°F to 20°F (7°C to 11°C) cooler than the inlet air.
Air temperature and flow rate through the heat pump
determines what this temperature difference will be. The
higher the flow rate the lower the temperature differential will
be. The higher the air temperature, the higher the differential
will be.
If the temperature differential between return and supply air
is not within the range stated above ensure the air filters are
clean and there is nothing blocking the air flow on either side
of the airstream or ductwork attached to the HPWH. Ensure
the ductwork is not smaller than the minimum required size
and or longer than the maximum length allowed in the Air
Flow & Ducting section of this manual. Ensure the evaporator
coil is not damaged (fins flattened) or dirty.
If the temperature differential continues to be outside the
range mentioned above call the toll free technical support
phone number on the back cover of this manual for further
assistance.
6 . When all of the above procedures are complete adjust
the tank temperature control set point to desired system
temperature, not to exceed 140°F (60°C). Remove all test
instruments and replace all cabinet doors.
This start-up refers to several tools and test instruments needed
to complete the procedure. See Required Tools and Materials on
page 16.
Turn off power to the water heater
before performing any service.
Electrical Shock Hazard
•
Label all wires prior to disconnecting
when performing service. Wiring errors
can cause improper and dangerous
operation.
•
Verify proper operation after servicing.
•
Failure to follow these instructions can
result in personal injury or death.
•
1. Ensure the Installation Checklist has been completed.
2 . Ensure the HPWH, storage tank and water system has been
purged of air and all valves are in the position for normal
operation.
3 . Turn on power at the circuit breaker or disconnect switch
serving the HPWH.
If the HPWH does not start immediately:
• Wait 5 minutes in case the anti short cycle timer has
halted operation. This control system feature protects
the HPWH from rapid short cycling that can cause
permanent damage to the unit.
• Ensure the operating set point on the tank temperature
control is adjusted high enough to initiate a call for heat.
The recommended setting is 120°F to 140°F (29°C to
60°C).
• DO NOT set the operating set point on the tank
temperature control above 140°F. See Water
Temperature Range on page 7.
• Ensure the Differential Set Point is not set too high.
Higher differential settings will cause greater temperature
swings in system temperature. Lower differential settings
can cause unit short cycling. The recommended setting
is 3°F .
• If the unit does not start after all of the above procedures
have been followed. Refer to the troubleshooting section
of this manual.
4 . Securely attach surface mount thermometers or temperature
sensors to the inlet (entering) and outlet (leaving) water lines
near the HPWH cabinet. If there are thermometers installed
in the inlet and outlet in close proximity to the HPWH water
connections they can be used for the following check.
Ensure the water outlet (supply) and inlet (return) valves
are fully open. Start the HPWH and allow it to operate for 5
minutes. With the HPWH operating record the inlet and outlet
temperatures.
During normal operation, the outlet line should be 8°F to 12°F
(4°C to 7°C) hotter than the inlet line. This is the temperature
rise through the heat exchanger inside the HPWH unit.
Note: Temperature rise and water flow rate through the heat
exchanger inside the HPWH are uniformly linked. As water