A.O. Smith AHPW-25, User'S Information Manual

Page: 23 / 44

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the storage tank. Use a suitable heat transfer compound
on the probe to ensure an accurate temperature reading.
5. If desired connect the Building Management System to
the Master Control Panel using the protocol determined
at the time of purchase. (we off er TCP and MSTP but this
MUST be determined prior to building the panel)
6. Insert the control fuse and power up the Master Control
Panel. Check the voltage into the terminal block and
make sure that it is 120V.
7. Reference page 25 for instructions on how to set up the
I.P. addresses for the Master Control Panel.
ROTATION DIRECTION
Scroll compressors, like several other types of compressors,
will only compress in one rotational direction. Direction of
rotation is not an issue with single-phase compressors since
they will always start and run in the proper direction. Three-
phase compressors will rotate in either direction depending
upon phasing of the power to L1, L2 and L3. Since there is a
50/50 chance of connecting power in such a way as to cause
rotation in the reverse direction, it is important to include
notices and instructions in appropriate locations on the
equipment to ensure proper rotation direction is achieved
when the system is installed and operated. Observing that
suction pressure drops and discharge pressure rises when the
compressor is energized allows verifi cation of proper rotation
direction. There is no negative impact on durability caused
by operating three-phase Copeland Scroll™ compressors in
the reversed direction for a short period of time, (under one
hour), but oil may be lost. Oil loss can be prevented during
reverse rotation if the tubing is routed at least 15 cm above the
compressor.
After several minutes of operation in reverse, the compressor
protection system will trip due to high motor temperature.
The operator will notice a lack of cooling. However, if allowed
to repeatedly restart and run in reverse without correcting the
situation, the compressor will be permanently damaged. All
three-phase Scroll compressors are identically wired internally.
Therefore, once the correct phasing is determined for a
specifi c system or installation, connecting properly phased
power leads to the identifi ed compressor terminals will ensure
proper rotation direction. Compressors ZB56K* to ZB220K*,
ZS56K* to ZS11M* and ZF24K* to ZF48K* have an electronic
protection unit (INT69SCY2) that will not let the compressor
operate if the phasing of the wires is incorrect.
STARTING SOUND
During the very brief start-up, a clicking sound is audible,
resulting from initial contacting of the spirals and is normal.
No start assist devices are required for single-phase compressors,
even if a system uses non-bleed expansion valves. Due to the
design of the Copeland Scroll, the internal compression components
always start unloaded even if system pressures are not
balanced. In addition, since internal compressor pressures are
always balanced at start-up, low voltage starting characteristics
are excellent for Copeland Scroll™ compressors. Moreover, if
low voltage conditions exist at start up, protector trips could
result.
This start-up refers to several tools and test instruments needed
to complete the procedure. See Required Tools and Materials
on page 15.
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 150°F
(29°C to 66° C).
• DO NOT set the operating set point on the tank
temperature control above 150°F. See Water
Temperature Range on page 4.
• Ensure the Diff erential Set Point is not set too high.
Higher differential settings will cause greater
temperature swings in system temperature. Lower
diff erential settings can cause unit short cycling. The
recommended setting is 10°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 fl ow rate
through the heat exchanger inside the HPWH are
START UP