System Operation Strategy - Dantherm HCC 2 ALU Manual De Servicio

Product description: System operation strategy

System operation strategy

Introduction
This section describes the operation strategy in various conditions. For a user specific running
operation see page 26.
In cold conditions where T1 is below -4°C and exhaust T4 is <+8°C the condensed water could
Defrost
built up as ice in the heat exchanger, blocking the air path and eventually destroying the heat
exchanger.
In order to prevent this sequence is initiated:
• The supply fan speed will decrease with 3 rpm/second until minimum RPM is reached.
• After 10 seconds at this speed the supply fan will stop completely, while the ongoing
exhaust fan is supplying warmer air into the heat exchanger component, to remove any
potential ice.
• When T4 yet again is >+8°C the supply fan will start at minimum RPM, and then increase
speed with 3 rpm/second until the original required speed is regained.
• If T4 becomes <+2°C during the speed increase cycle, the supply fan will decrease speed
again.
• If T1<= -13°C for more than 4 minutes and 25 seconds, even with defrost mode active, the
unit will stop all operation for 30 minutes, and reattempt previous operation condition. If
electrical preheat is present, this total off mode is disabled.
The defrost operation will create an under pressure inside the house, so if fireplace mode is
enabled, and defrost is necessary; the unit will stop all operation in 4 hours instead. Set-
points cannot be changed.
When defrost is active any connected remote control will show
when defrost has shut all off, the display will flash the T1 temperature
Preheat If the preheater is installed, the unit will add electrical heat to the T1 incoming outside air, in
order to reduce defrost situations, and increase the supply air temperature.
(Accessory)
• Preheater can be "master" enabled/disabled on the wireless remote control in installer
mode
• Preheat is applied after the T1 sensor.
• If outside temperature is <-3°C or supply air is < 16,5°C the preheater will switch on with
10% power.
• The power will increase/decrease 10% for each 60 seconds depending on the T1 or T2
temperature.
Temperature set-points are fixed.

in the display, and
11