Start-Up Procedure - Modine Manufacturing SSD Installation And Service Manual

START-UP PROCEDURE

7. Check the operation of the condensate pump by pouring
7-8 ounces of water down the pump outlet, switch the
unit on, select cooling mode and the lowest possible
temperature set point then observe the water being
pumped from the unit.
8. Where fitted, check the operation of the hot water valve
or the electrical heat elements by switching the system to
the heating mode and selecting the highest possible
temperature set point.
9. The compressor signal Y1 (disconnected from the indoor
unit in step 1) can now be re-connected and main power
applied to the system.
Note: The 24V power for the indoor unit control circuit is
supplied from a unit factory-installed transformer. When the
indoor and outdoor units are supplied from separate main
supplies, care must be taken to ensure that the outdoor unit
is isolated whenever the indoor unit power is removed.
Failure to do so may result in freeze ups and other damage
to the unit.
Chilled Water Unit – Control Circuit Checks
A thorough pipe work check and pressure test should be
performed before the unit controls are set up
1. Isolate the unit from the chilled water supply. A system
electrical check can now be carried out.
2. Switch on the indoor unit via the infrared/pendant
transmitter or wall mounted thermostat and check that
the fan cycles correctly. - Note, in some models there is a
2 minute fan run on time to remove residual heat from
the unit, if the unit is switched off during the heating
mode.
3. On models with microprocessor controls, check that the
High, Medium and Low fan speeds are operating
correctly by changing the fan speed via the transmitter.
4. On medium and large size units, check that the motorized
vane sweep functions correctly by toggling the function on
or off, either via the transmitter (micro units) or via the toggle
switch on the side of the electrical panel lid (electro-
mechanical units).
5. On micro controlled units, should it be required, check
that the built-in timer function is programmed and
operating correctly. When the timer is activated, the red
LED on the fascia display panel should be lit.
6. Check the operation of the condensate pump by pouring
7-8 ounces of water down the pump outlet, switch the
unit on, select cooling mode and the lowest possible
temperature set point then observe the water being
pumped from the unit.
7. Check the operation of the chilled water valve by
switching the system to the cooling mode and forcing a
call for cooling.
8. Where fitted, check the operation of the hot water valve
or the electrical heat elements by switching the system to
the heating mode and forcing a call for heat.
9. Allow chilled water to enter the unit and vent air from the
unit by opening the 1/4" air bleed. Re-tighten the bleed
screw once all air has been removed.
10. Repeat steps 1-4 above for all units in the same system.
The units are now ready for the system balance to be
performed.
8
Sequence of Operation
Electro-Mechanical Controls: A 24V signal from the
thermostat to terminal G supplies power the blower motor(s),
condensate pump and vane motor (if equipped). A toggle
switch on the control box can be used to switch the
oscillating vanes on or off. The condensate pump will run
continuously, as long as the blower is energized. A call for
heating, at terminal W, or cooling, at terminal Y, will energize
the water valve actuator and allow water to flow through the
cassette coil. When the call for heating or cooling is satisfied
the valve will close.
If the temperature drops below the set-point of the coil freeze
stat, the water valve with automatically open to circulate
water through the coil.
If the condensate float switch detects a high level of water in
the condensate tray, the switch will open, activate the
condensate pump and disable the heating/cooling signal
until the water level drops down to normal.
Micro-Processor Controls: See the Infra-Red Remote
Controller Installation and Service Manual, 8-507.
8-504.6