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Because Mini Ventilators have a low frost threshold, frost
control options are not necessary in many climates. Where
outdoor temperatures may drop below the frost threshold
during the MV operational hours, exhaust only frost control
option is available.
IX - Standard Features
Low Am bi ent Kit
Extremely cold outdoor air temperatures can cause
moisture condensation and frosting on the energy
recovery wheel (ERW). The outside temperature below
which frost will begin to accumulate is referred to as the
Frost Threshold Temperature
, and is a function of both the
indoor DB temperature and the indoor relative humidity
See Table #2.
Frost formation causes reduction of airflow
through the ERW; therefore, without frost control, energy
recovery and airflow may be significantly reduced.
A thermostat control is provided to shut down the supply
blower when outdoor temperature drops to a field-selected
frost control setting. The thermostat is located within the
outdoor air intake hood. To avoid depressurization of the
conditioned space, automatic or pressure operated fresh
air dampers may be required as part of the ventilation
system. Factory setting is 20
o
F.
of the circuit board. The following diagram details the
jumper location for each mode of operation:
Temperature Control (See Figure 7)
The temperature mode of operation incorporates one
sensor located in the fresh air intake of the ERV. The Start
Stop Jog sequence is activated when the outside air
temperature is between 70°F and 40°F. The SSJ module
provides two potentiometers in order to adjust the Low and
High temperature range of the start stop jog sequence. To
adjust the High temperature range, place a Multimeter on
the COM and HIGH test points. Use a screw driver to
adjust the potentiometer to the desired VDC representing
the temperature. The Low temperature range is adjusted
by placing a Multimeter on the COM and LOW test points
with the adjustment of the potentiometer to the desired
VDC representing temperature. The VDC can be
calculated for a desired temperature using the following
formula: VDC = 0.1429 x (Temperature) - 5.7143.
FROST THRESH OLD TEM PER A TURE (OD DB)
IN DOOR
RH (%)
IN DOOR DB TEMPERATURE
70
o
F
72
o
F
75
o
F
80
o
F
20
-14
-13
-11
-8
30
-3
-2
-1
3
40
5
7
9
11
50
13
13
15
18
60
18
19
21
26
Table #2
Rotation Sensor
The circuit indicates the absence of pulses, within a
specified time range, provided by a magnetic sensor
detecting a magnet mounted on wheel surface. After the
initial time delay of approximately 5 seconds from circuit
power up, if the sensor fails to provide a signal pulse (no
wheel rotation) within approximately 5 additional seconds,
the alarm relay will activate the latch (until circuit powers
down) providing a 5 amp contact closure output. This
would indicate no wheel rotation and/or magnet in the
system has stopped at the magnetic sensor pickup point. If
the pulse (wheel rotation) is detected within the
approximately 5 second time period, the alarm relay will
remain open. No field timing adjustment of any type will be
required.
Climate Smart
[Patent Pending]
There are three modes of control strategies available.
Temperature, Single Enthalpy, or Enthalpy and
Temperature control.
Mode of Operation
The mode of operation is selected with the adjustment of a
jumper. The jumper is located at the lower center position
Figure 7
Enthalpy Control (See Figure 8)
The enthalpy mode of operation incorporates one enthalpy
sensor located in the fresh air intake of the ERV. The SSJ
module compares the outdoor enthalpy to a preselected
set point. The value of the set point can be identified on a
psychometric chart with the standard control curves as A,
B, C or D. The set point can be selected as an aggressive
set point A for higher levels of free cooling or a
conservative set point D for lower levels of free cooling.
The Enthalpy sensor provides a 4-20 mA (0-100%) signal
proportional to the selected control curve A, B, C, or D. The
SSJ module begins the start stop jog sequence when the
Enthalpy sensor reports 60%. The Enthalpy 60% setpoint
for each control curve is detailed in the following table:
Figure 8
