Gas Boiler (Optional); Heat Recovery Wheel (Optional); Cooling Capacity And Electrical Energy Meter (Optional); Humidifi Cation (Optional) - Carrier 50FF Series Control Manual

12 - COMPONENTS MANAGEMENT

12.13. Gas boiler (optional)

The control has a proportional output 0/10V (Y2 - connector J5)
where a gas boiler with proportional actuator can be connected.
The boiler connection is managed by the control, in HEATING
mode, through an ON/OFF signal of the digital output NO5.
● In cooling-only units, the boiler is activates in the same way as
an electrical heater with one or two stages.
● In heat pump units it is possible to choose three diff erent
methods for controlling the boiler. This can be done on the
screen D. GASCONFIG of the MAIN MENU:
- Operation after compressors as one electrical heater stage
(both option not compatible).
- Operation instead of compressors.
- Operation instead of compressors if the outdoor temperature
is lower than the value set (5ºC by default).
When the return temperature drops below the value setpoint,
the boiler will start to operate. The power control is carried out in
accordance with the temperatures of the supply air and return air.
The control compares both temperatures. If the supply temperature
is excessively high, the control limits the power supplied by the
boiler despite the demand. This comparison avoids the stratifi cation
of the hot air masses and keeps the supply temperature below the
safety value (55ºC by default), which stops the boiler.
Moreover, the control compares the supply temperature and the
ambient temperature to improve the feeling of thermal comfort.
The gas boiler integrates its own operating control, as well as its
own safety devices. The "50FC" control receives a safety signal
from the boiler in the event of failure (digital input DI5). This signal
only indicates the failure.
Important: The "50FC" control manages the start-up and stop of
the circulation pump of the water circuit. The pump will start-up
10 seconds before the boiler. The pump stop will be delayed 180
seconds with regard to the boiler.

12.14. Heat recovery wheel (optional)

The control can manage a rotary heat exchanger connected on
the output NO7 (connector J14), or on the outputs NO1 or NO4
of the pCOe expansion card with address 8.
This confi guration is performed on a screen of the Group G.
GENCONFIG (protected by level 3 password).
The management may be:
● On-off: this will function whenever there is demand for
COOLING or for HEATING and when the temperature conditions
for outlet, return and mixing air allow for an opening of the
outdoor air damper of 5% for a period of time greater than 10
seconds (values set by default).
● Variable: the variable wheel speed will depend on the minimum
value of the exhaust temperature and the recovery temperature
on the wheel.
If this value is lower to 6°C, the speed of the wheel decreases
until reaching a minimum value fixed of 10% when the
temperature is lower to 1°C (by default).
The control of the wheel speed is carried out via a 0/10V (Y1)
proportional output on the pCOe expansion card with address 8.
32
12.15. Cooling capacity and electrical energy meter
(optional)
The control can manage a energy meter. The readings that it
realizes are visualized on the Graphic terminal.
The energy meter will be connected on the Field-bus of the μPC
MEDIUM board by means of one RS485 card, with address 5
(9600 bps, 8 bits of data, 2 stop bits without parity).
Calculation of the cooling/heating capacities
To perform this calculation, it's necessary to connect two RS485
enthalpic probes: one for the mixing air (placed before the indoor
coil) and other for the supply air (placed after the indoor coil).
These probes will be connected on the Field-bus of the control
board via two RS485 cards, with address 132 for the mixing probe
and address 133 for the supply probe.
12.16. Humidifi cation (optional)
The control can manage an on/off humidifi er connected on the
output NO7 (connector J14), or on the outputs NO1 or NO4 of the
pCOe expansion card with address 8.
This confi guration is performed on a screen of the Group G.
GENCONFIG (protected by level 3 password).
A humidifi er with proportional control can be connected on the
0/10V output (Y1) of the pCOe expansion card with address 8.
The control of the safety devices and alarms is carried out by the
humidifi er.
The humidifi er operating signal is produced when the relative
humidity of the return air is lower than the humidity setpoint
established (55%) minus the diff erential (5%).
HUMIDIFICATION
C1
Hr
Hc
Zm/2
Band

12.17. Heat recovery coil (optional)

The control has a proportional output (Y2 - connector J5) where
a three-way valve can be connected (3-WV) to manage a heat
recovery coil.
Note: 3-way valve is supplied for installation outside the unit
50FF/FC.
Electronic regulation uses the same inputs and outputs for the
management of the heat recovery coil (HRC) and the hot water
coil (HWC), so these elements are not compatible.
The function of the heat recovery coil is to pre-heat the air that will
pass through the main indoor coil. For this, it uses the temperature
of an outdoor water installation.
The priority of the activation of this coil with respect to the
compressors is established by means of a parameter.
Hr: Relative humidity of return air
Hc: Humidity setpoint
Zm: Dead zone
Band: Humidity control band