MORTEX
PRODUCTS
INC
FORT
WORTH,
TX
76106
Page
9
13.
Check the evaporator condensate drain pan for any debris
and ensure the pan is properly draining by pouring water
into the drain to check it.
14.
Remove any excess water that may have spilled from
checking the evaporator condensate drain.
15.
Reinstall the blower assembly and secure the assembly
using the screws that was removed in step 5.
16.
Reinstall the control box cover and secure it to the control
box with the screw that was removed in step 4.
17.
Reinstall the lower access door on the furnace.
18.
Reinstall the upper access door on the front of the
evaporator coil compartment.
19.
Follow the instructions exactly as shown in Startup and
Shutdown Section in this manual to properly startup this
appliance.
SECTION III: FURNACE CONTROLS
This section discusses the furnace controls and how they
operate. Refer to Figure 10 for component locations.
1.
The Limit Controls
– Each electric heater element has a
limit control directly in front of it to sense overheating of
the element and open if the temperature gets above the set
point of the limit control.
2.
The Heater Relays
– The electric heater relays simply
turn the heater elements on and off. The relays are
controlled by the thermostat. On a call for heat 24 VAC is
sent to the relay(s) 24 VAC coil energizing the relay.
When the call for heat has been satisfied the 24 VAC is
removed from the relays 24 VAC coil de-energizing the
relay(s).
3.
Cooling Time Delay Relay (TDR)
– The cooling relay is
used only when 24 VAC is on the “G” terminal from the
thermostat. The relay controls the blower on time delay
and is adjustable from 0 – 30 seconds. The factory setting
is approximately 13 seconds.
4.
Circuit breakers
– The circuit breakers are designed as
over-current protection for the electric heaters only. The
circuit breakers MUST NEVER be used for over-current
protection for the transformer, 24 VAC circuit, or the
blower motor.
5.
3 Amp Fuse
– This fuse is used for over-current
protection of the 24 VAC circuit.
6.
Transformer
– The transformer is used to step down
voltage from 240 VAC to 24 VAC. The transformer
provides the required 24 VAC for the system control
circuit.
7.
Blower Motor Isolation Relay
- This relay is used to
load the TDR when using an X-13 motor or for isolation
between the high and low speeds of a PSC motor. The
wiring has been designed so that the normally closed
contacts are used for heating and the normally open
contacts are used for cooling. The relay coil is energized
after the thermostat has a call from the “G” terminal
starting the time delay cycle on the time delay relay. Once
the time delay relay has reached the delay setting the relay
contacts close energizing the isolation relay coil. The
normally closed contacts on the isolation relay open and
the normally open contacts close, energizing the motor on
the selected cooling speed.
X-13Motor Isolation Relay
- This relay is used on the X-13
motor as a load for the time delay relay so the relay will
operate properly. The wiring has been designed so that the
normally closed contacts are used for heating and the normally
open contacts are used for cooling. The relay coil is energized
after the thermostat has a call from the “G” terminal starting
the time delay cycle on the time delay relay. Once the time
delay relay has reached the delay setting the relay contacts
close energizing the isolation relay coil. The normally closed
contacts on the isolation relay open and the normally open
contacts close, energizing the motor on the selected cooling
speed.
SECTION IV: SEQUENCE OF OPERATION
Continuous Blower
The thermostat has a manual fan switch that can be moved to
the “
On”
position or it can be programmed for
continuous
fan
operation. This setting causes the thermostat to complete the
circuit between “R” and “G” terminals causing the time delay
relay to start the time delay cycle. Once the time delay relay
has completed the on-delay cycle the contacts will close
sending voltage to the isolation relay coil. The isolation relay
will close the normally open contacts (Terminals #2 and #4)
sending voltage to selected indoor blower motor speed tap
connected to terminal #4. The normally closed contacts
(Terminals #5 and #6) will open.
The indoor blower will operate continuously until the fan
switch on the thermostat has been switched from on to auto.
Figure 9: Component Locations
Intermittent Blower - Cooling
The thermostat has a manual fan switch that can be moved to
the “
Auto”
position or it can be programmed for
auto
fan
operation. When the thermostat calls for cooling, a circuit is
completed between the “R”, “Y” and “G” Terminals. The
indoor fan motor is energized from the “G” terminal on the
thermostat causing the time delay relay to start the on-time
