11
OPERATION
Winter:
Humidity control is very important during the winter
months. This is when problems will be most apparent
since condensation on the windows will often occur. The
colder the outside temperature, the greater the risk of
condensation in the home. The average relative humidity
should be maintained between (30% and 60%) to avoid
condensation. Low speed continuous ventilation with high
speed override is recommended.
A Heat Recovery Ventilator (HRV) is designed to bring fresh air into a building while exhausting an equal amount of stale air. During the winter
months, the incoming cold fresh air is warmed by utilizing the heat recovered from the stale air before it is exhausted to the outdoors. During sum-
mer months when the indoor space is air conditioned, the HRV will help in cooling the incoming fresh air with the stale air that is being exhausted.
The VHR 704R is designed to run continuously or on intermittently, giving the homeowner complete control over their air quality. Continuous low
speed ventilation is recommended, which will help eliminate carbon dioxide, voc’s and other gases as well as freshen up the home. Intermittent
high speed ventilation can be obtained through a variety of optional remote controls found in this manual. Below are some examples of seasonal
operation of an HRV.
Spring:
Temperatures are more moderate and become
warmer each day. To keep the humidity and tem-
perature uniform, set the dehumidistat higher (if
installed). You may also switch the HRV to standby
mode if desired.
Summer:
The air is sometimes hot and humid. To stop the warm
humid air from entering, set the dehumidistat at its high-
est level. If the Intellitek series controller is installed, the
air exchanger can be set to cycle the unit on and off as
desired from that wall control. However, continuous ven-
tilation is recommended.
Fall:
Rain and rapid temperature changes make it difficult
to control the internal humidity level and may result
in condensation on the windows. A remote dehu-
midistat may help give greater control over the
inside environment.
The entire line of SHR/VHR series Heat Recovery Ventilators comes equipped with Fantech's new electronic uni-control board which offers a wide
variety of features making it the ultimate ventilation control system. Fantech engineers have used the latest technology to provide solid, trouble free
operation under any conditions.
The Fantech uni-control board offers stand alone operating capabilities as well as an exclusive 2 wire communication to most external controls. The
trouble-free optional controls include: two different rotary dial dehumidistats, an air quality sensor (3 wire communication required), a 15 minute
remote push-button timer, as well as the most sophisticated line of remote wall mounted controls, the Intellitek 5MR.
An on-board diagnostic LED helps find problems quickly and efficiently. For example the LED can be used to signal a broken or shorted electronic
wall control wire. Electronic air temperature probe gives this board accurate readings in order to minimize unnecessary defrost operation, and the
on-board jumpers provide the user with the option of adjusting defrost time and sequence to optimize performance under abnormal conditions. The
defrost operation
is automatic and is usually never adjusted.
2. Defrost
The automatic defrost sequence is activated at
an outdoor temperature of 23°F (-5°C) and
lower. During the defrost sequence, the fresh air
is interrupted momentarily and indoor air is
allowed to recirculate in the exchanger to maxi-
mize the effectiveness of the defrost strategy.
The unit then returns to normal operation until
the next defrost sequence.
MODES OF OPERATION
1. Continuous / Ventilation Mode
In this mode of operation both fans are operating
and exchanging air with the outside. The heat
recovery ventilator (HRV) constantly exchanges the
air at the rate you select, either at low or medium
speed, and switches to high speed when activated
by an optional remote control. The "Low" and "Med"
fan speed selection will cause the unit to operate
in continuous exchange mode at an exchange rate of 35% and 50% maxi-
mum airflow rating respectively. Continuous mode is recommended, since
pollutants are slowly but constantly being generated in your house.
Air to
Outside
Air from
Outside
Air to
House
Air from
House
Air to
House
Air from
House
