Water Coil; Optional Filter And Filter Access; Optional Water Flow Control Valves; Gerätecodes - Carrier 42NH Installation, Operation And Maintenance Instructions

4.1.3 - Fan wiring
4.1.3.1 - Multi-speeds unit with electrical box option
This option allows the installer to connect the unit to a
terminal board inside a electrical box. The electrical box
can be opened with a screw driver.
Three of the available five speeds are connected -
(maximum speed = R1, minimum speed = R5). See Fig. 13.
which describes wiring colors.
The control box option permits changing the speed wiring
without access to the motor. See Fig. 13.
4.1.3.3. Multi-speed unit with HDb or ntC controller
When the unit is delivered with an HDB or a NTC
controller, three of the five speeds are connected to a
MOLEX connector: see Fig. 14 for HDB and NTC wiring.
The numbering and the colors of the wiring are similar to
the electrical box (see Fig. 13).

4.2 - Water coil

4.2.1 - Coil removal procedure
WARNING: Disconnect the power supply to the unit before
carrying out any work on the unit.
• Close the isolating valves on the manifolds.
• Empty the water in the unit by opening the drain
valve (see Fig. 15)
• Unscrew the union nuts to disconnect the flexible
water pipes.
• Remove the valve actuators taking care to identify the
cooling and heating valves.
• Disconnect the flexible condensate drain pipe held in
place by a collar (the collar is not supplied by Carrier).
• Remove the two-way or four-way water flow control
valve bodies. Depending on the unit configuration the
four-way valve coupling may be fitted with a heating/
cooling changeover switch. If so, do not remove it.
• Loosen the four fixing screws. Pull out the drain pan
and coil assembly (the drain pan remains attached to
the unit for approximately 100 mm) until the coil is
completely detached. Then remove the coil from the
drain pan.
• Replacement is by the reversal of the procedure des-
cribed above. Ensure that all gaskets are changed (new
gaskets fitted) and that the inlet and outlet connections
to the coil are made correctly using an appropriate
sealing compound applied to the valve body.
• Bleed all air from the coil during refilling.
WARNING: Take care when tightening the valve body to
the coils (15 N·m is sufficient) to ensure they are not
damaged.
4.2.2 - Coil inlet/outlet and cooling/heating side positions
Water inlets/outlets, all sizes : Fig. 15.
WARNING: Carefully observe the direction indicated by
the arrow on the valves, based on the valve type.

4.3 - Optional filter and filter access

4.3.1 - Description
The Carrier unit is fitted with G1 filter as standard. As an
option, a G3 Filter can also be provided (85% gravimetric
filter) according to EN 779 standard. The G3 filter is
compliant to M1 fire rating (according to NFP 92-507
standard).
Different filter access are available:
• Unit without rectangular flange air inlet (plain inlet):
access is from the rear of the unit.
• Unit with rectangular flange air inlet : access is from
below (trapdoor).
4.3.2 - Air filter replacement
Air filters should be changed regularly. Filter life depends on
the rate at which the filter becomes clogged, which depends
upon the cleanliness of the working environment.
If clogged filters are not changed they can increase the air
pressure drop, trapped dust particles may be given off and
entrained in the air supply, and the general performance of
the unit may be degraded (as the air flow reduces).
NOTE: When installing a unit in a ceiling void, check
that no T-bars will obstruct filter access and removal.

4.4 - Optional water flow control valves

These valves are either two-way or four-way type (three-
way with integral bypass). The body of the valve is
designed to withstand a 16 bar operating pressure.
With this option, the couple (valve + actuator) is usually
normally closed (NC).Thus, the water flow is null in case of
power cut. To fill the installation, to equalise the water
circuits and to purge the units, the actuators must be
connected to the power supply and the valves must be
opened via the controller (thermostats or BMS).
For the replacement of these components refer to the
chapter ''4.4.1. - Actuator replacement procedure'' .
The electrothermal actuator provides an on/off control.
The actuator supply is 230 V a.c.
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