Hvac CVH8, Руководство по обслуживанию

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CVH8, HVH8, TVH8, VA9, HVA9, TVA9: APPLICATION GUIDELINE & SERVICE MANUAL
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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Suction Thermistor (OST)
Suction Thermistor is used for assisting in EXV control and must be
secured on the suction tube and aligned longitudinally to the vertical
surface of the tube axis (see Fig. 5 ).
A14023A
Fig. 5 – Suction Thermistor (OST) Attachment
(On Suction Tube)
Discharge Thermistor (ODT)
Discharge Thermistor is used for protection against over temperature of
the compressor. The ODT is located on the compressor discharge
stub-out (see Fig. 6 ).
A14024
Fig. 6 – Discharge Thermistor (ODT)
Crankcase Heater Operation
This unit has an internal crankcase heater that will be energized during
the off cycle and is intelligently demanded by the system to prevent the
compressor from being the coldest part of the system thus enhancing the
reliability. The crankcase heater will function as needed any time the
outdoor unit is powered. The indoor unit and UI do not need to be
installed for the crankcase heater to operate properly.
The compressor windings will occasionally be energized during the OFF
cycle (depending on the length of the OFF cycle) to start the stator heat
operation, thus maintaining a sump temperature that is essential for
compressor reliability. The compressor will not run during this process.
Time Delays
The unit time delays include:
• 3.5 minute time delay after last cycle, initial power up, return from
brown-out condition. To bypass this feature, momentarily short and
release Forced Defrost pins.
• At the end of every compressor ON cycle, there will be 150 seconds
of PEV open period for pressure equalization followed by 15 seconds
of PEV Off period before the next compressor ON cycle. This delay
cannot be bypassed as it helps compressor reliability.
• 15 second delay at termination of defrost before the auxiliary heat is
de-energized.
• 10 minute sump warm-up delay. This delay is at the beginning of each
high voltage power up.
COMMUNICATION
AND
STATUS FUNCTION
LIGHTS
Observer Wall Control, Green Communications (COMM) Light
A green LED (COMM light) on the outdoor board (see Fig. 7 and Fig. 8 )
indicates successful communication with the other system products. The
green LED will remain OFF until communication is established. Once a
valid command is received, the green LED will turn ON continuously. If
no communication is received within 2 minutes, the LED will be turned
OFF until the next valid communication. The green LED will be turned
off when using a standard 2-stage non-communicating heat pump
thermostat.
Amber Status Light
Amber colored STATUS light indicates operation and error status. See
Table 10 for definitions.
• Two minute time delay to return to standby operation from last valid
communication.
Defrost
This wall control (WC) offers 4 possible defrost interval times: 30, 60
and 90 minutes, or AUTO. The default is AUTO.
Defrost interval times: 30, 60, and 90 minutes or AUTO are selected by
the Observer Wall Control User Interface if using UI. The 90 minute
selectio°n will default to 60 minutes at ambient below 37°F. The UI
setting will supersede the dip switch settings on the control board if not
the same.
If using non-communicating thermostat, defrost intervals are set using
dip switches on outdoor control board (see Fig. 7 and 8). AUTO defrosts
adjusts the defrost interval time based on the last defrost time as follows:
• When defrost time <5 minutes, the next defrost interval=90 minutes.
(outdoor temperature above 37°F)
• When defrost time 5-7 minutes, the next defrost interval=60 minutes.
• When defrost time >7 minutes, the next defrost interval=30 minutes.
The control board accumulates compressor run time. As the accumulated
run time approaches the selected defrost interval time, the control board
monitors the coil temperature sensor for a defrost demand. If a defrost
demand exists, a defrost cycle will be initiated at the end of the selected
time interval. A defrost demand exists when the coil temperature is at or
below 32°F (0°C) for 4 minutes during the interval. If the coil
temperature does not reach 32°F (0°C) within the interval, the interval
timer will be reset and start over.
• Upon initial power up the first defrost interval is defaulted to 30
minutes. Remaining intervals are at selected times.
• Defrost is only allowed to occur below 50°F (10°C) outdoor ambient
temperature.
The defrost cycle is terminated as described below.
• When OAT is > 25°F (+3.89°C), defrost terminates if outdoor coil
temperature (OCT) > 60°F (+15.6°C). And a minimum of one (1)
minute defrost length.
• When OAT ? 25°F (+3.89°C), defrost will terminate if OCT is >45°F
(+4.4°C) and a minimum of 2 minutes defrost length.
• Or 10 minutes has passed.
At the defrost termination, the outdoor fan will turn on 10 seconds
before the reversing valve switching.
NOTE: Compressor speed during defrost will go to defrost speed.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage or
improper operation.
In order to minimize the ambient influence, make sure the thermistor
curved surface hugs the pipe surface and is secured tight using the wire
tie fished through the original slot insulating polymer body.