Enertech Global
88
EAV - EME/EMD Rev. A Models
Installation and Operations Manual
EEV (Electronic Expansion Valve)
The EEV modulates as needed to maintain 8°F superheat. Above
the setpoint causes the EEV to open and below causes it to
close. The EEV remains completely closed when the system is
idle. Movement of the valve can be observed on the LEDs of the
driver in the lower control box.
Note
: In some conditions it is normal for the EEV to open 100%
and the superheat to be above 8°F.
Defrost Controls
The EAV outdoor unit has a built-in defrost control that monitors
air coil temperature, outdoor air temperature, run time,
compressor RPM, and operation mode. In the heating or DHW
mode, there are two types of defrost cycles, active defrost and
passive defrost.
Passive Defrost
If the outdoor temperature is above 39°F and the compressor is
not operating but the air coil temperature indicates that defrost
is necessary, passive defrost starts. In passive defrost mode,
the reversing valve does not shift. The fan runs at high speed
to attempt to increase coil temperature with the outdoor air
temperature. If there is a compressor demand, passive defrost
stops and the compressor starts. Active defrost may be enabled,
depending upon coil temperature when the compressor is
running.
Active Defrost
Active defrost mode starts when the air coil temperature
(thermistor BT16) falls below 27°F. Active defrost can occur as
infrequently as once every 12 hours (for calibration purposes)
or as often as once every 90 minutes, depending upon coil
temperature, outdoor air temperature, and amount of moisture
in the air. Time until “active defrosting” is shown in minutes
on the indoor module HMI display. During active defrost, the
reversing valve shifts to cooling mode, the fan stops, and the
compressor continues to run until the coil temperature (BT16)
reaches 37.4°F or the discharge gas temperature reaches 140°F.
Defrost mode continues for 90 seconds once either temperature
is reached.
Unsuccessful Defrost
If the unit is unable to finish an active defrost cycle ten times in
a row (there is no time limit), an alarm will be displayed, and the
control will not attempt to operate the compressor. The power
must be cycled to reset the unit. There are several possible
reasons for an unsuccessful defrost, as follows:
1.
When defrosting has gone on for longer than 15 minutes.
This may be due to a strong wind effect on the air coil. A
wind shield may be necessary.
2.
When the water/antifreeze temperature on the line
entering the outdoor unit (thermistor BT3) falls below 50°F.
3.
If the temperature of the air coil continues to drop.
Insufficient airflow through the air coil or insufficient water
flow to the outdoor unit should be inspected and checked if
it is unable to complete a successful defrost. If the unit has
a significant amount of leaves around the air coil or if the
coil needs cleaning, the coil may not be able to transfer heat
properly. Insufficient water flow is generally due to a pump
failure and should be displayed as a water flow fault at the HMI.
Safety Defrost
If the air coil is too cold, a “safety defrost” starts. This defrost
cycle can be started earlier than a normal active defrost. If there
are ten safety defrost cycles in a row (there is no time limit),
an alarm will be displayed, and the control will not attempt to
operate the compressor. The power must be cycled to reset the
unit.
Manual Defrosting
Defrost may be activated manually for service or testing
purposes. A toggle switch is located in the “Manual Control”
menu at the HMI.
Troubleshooting
Note:
Work behind covers secured by screws.
Note:
As EAV can be connected to a large number of external
units, these should also be checked.
Note:
In the event of action to rectify malfunctions that require
work within screwed hatches the incoming electricity must be
disconnected at the safety switch.
Note:
The alarm is acknowledged on the EME/EMD module or
by the voltage to the heat pump being interrupted and then
restarted.
The following tips can be used to rectify comfort issues:
Basic Actions
Low hot water temperature or a lack of hot water:
This part of the fault-tracing section only applies if the heat
pump is connected to the hot water heater.
•
Large hot water consumption.
- Wait until the hot water has heated up.
•
These settings are made on the display on the indoor
module/control module.
- See the section for the indoor module or control module.
•
Clogged strainer.
- Check whether alarm “high condenser out” (162 is an
information message. Check and clean the strainer.
Low Room Temperature In Heating/High Room
Temperature Cooling
•
Thermostats off in several rooms.
- Set the thermostats to max in as many rooms as possible.
•
Zone panel is not showing heating/cooling calls.
- Check settings.
•
Incorrect settings in indoor module or control module.
- See the manual for the indoor module / control module
(EME/EMD Series).
•
Incorrect flow across the heat pump.
- Check whether alarm “high condenser in” (163) or
“high condenser out” (162) are info messages. Follow the
instructions for adjusting flow rate.
EAV not in operation
EAV communicates all alarms to the indoor module/ control
module (EME/EMD Series).
•
Ensure that the EAV is connected to the power source and
that compressor operation is required.
•
Check the indoor module/control module (EME/EMD
Series). See Indoor Module section in this manual.
•
Check that the addressing of EAV is correct.
•
Check that the communication cable has been connected.
Ice build-up in the fan, grille and/or fan cone on the outdoor
module
•
De-icing fan is not activated.
- Activate “de-icing fan” (menu 5.11.1.1).
Section 9: On-Board Controls
