logo de l'entreprise LTB

Le spécialiste de la climatisation
sans unité extérieure

Information and precautions

for FA and Optimum

Air inlet and outlet configuration

configuration: air inlets and outlets top view

FA centrifugal unit panels are interchangeable to allow maximum flexibility in installation inside the building. There are four possible configurations for the air inlet and outlet to which the ducts must be connected (see drawing).

Don’t forget to specify the configuration you want when you place your order. Unless otherwise specified, we manufacture the machine in configuration n°1. It is possible to change the configuration after delivery. This operation must be carried out on the ground according to a procedure available on request.

Air filter

We recommend the use of an air filter for reversible centrifugal units. In hot mode, the unit’s heat exchanger acts as an evaporator, and the condensation water collects and agglomerates dust, accelerating its clogging. To limit this phenomenon, we recommend using the class G3 filter we offer as an option for FA units. If the outdoor environment is particularly dusty, this filter may also be necessary for cooling-only (non-reversible) units. Note: OPTIMUM centrifugal units are all reversible and have a G2 air filter as standard.

Air inlet temperatures (air-conditioning mode)

FA and OPTIMUM condensing units are designed to operate in air-conditioning mode, drawing in outside air at a minimum temperature of +20°C and a maximum of +40°C.

Too high an outside temperature will result in loss of performance, premature compressor wear and possibly cut-out of the HP pressure switch.

If the outside temperature is too low, this can lead to operating problems and even premature compressor failure.

If the air is too cold, subcooling of the condenser will be too great. This will result in low HP pressure and compressor operation outside its normal operating range. However, operation in cooling mode with an air inlet temperature below 20°C is possible with the “Condensation control” option.

The minimum and maximum values of +20°C and +40°C are given for an air flow equal to the machine’s nominal air flow. With higher or lower air flow, these values are modified. Consult us if necessary.

Air inlet temperatures (heating mode)

In heating mode, FA reversible and OPTIMUM condensing units are designed to operate by drawing in outside air at a minimum temperature of -7°C and a maximum of +20°C. Operation outside this temperature range will lead to operating problems, premature wear or even compressor failure, and possibly to HP cut-out. As in cooling mode, minimum and maximum values are given for an airflow equal to the machine’s nominal airflow.

Condensation control (“All-season kit”)

The “condensation control” option can be used in cooling mode in spring, autumn or winter, when the outside air temperature is below +20°C.

It prevents overcooling of the condenser by controlling the speed of the unit’s fan, adapting the air flow to maintain the condensing temperature at an optimum value.

Industrial applications Sizes 40, 50 and 64 in the FA range are three-phase (with neutral) models, and are particularly suitable for industrial applications. If required, we can adapt the machines for use with a three-phase supply without neutral.

Industrial applications

Sizes 40, 50 and 64 in the FA range are models supplied with three-phase current (with neutral) and are particularly suitable for industrial applications.

If required, we can adapt the machines for use with a three-phase supply without neutral.

Sheathing and ventilation: precautions

Our FA and OPTIMUM centrifugal units evacuate (respectively capture) heat from an outside air stream in cooling mode (respectively in heating mode).

The unit must therefore be ducted to bring outside air into the machine and then discharge it outside.

The unit’s centrifugal ventilation offers high static pressure, from 100 to 230 Pa depending on the model (see data tables), which allows duct lengths of up to 5 m, if the cross-sections are respected.

Nevertheless, it is important to ensure that the air pressure losses induced by the suction and discharge grilles and ducts, and the air filter where applicable, are compatible with the flow rate expected for nominal machine operation.

It is also advisable to ensure that the arrangement of suction and discharge grilles does not induce recirculation of discharge air in the suction.

There is no need to duct the suction if it takes place in a sufficiently large volume that does not communicate with the air in the rooms being treated.