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Page 23

Installer’s Guide

Operation of the unit heating and cooling cycles is automatic when 
the system is set to 

HEAT

 or 

COOL

 (the optional automatic change-

over thermostat, when set to 

AUTO

, automatically changes to heat 

or cool with an appropriate room temperature change). The fan can 
be set  to 

ON

, causing continuous evaporator (indoor) fan operation 

or set to 

AUTO

 causing fan operation to coincide with heating or 

cooling run cycles. Continuous fan mode during cooling operation 
may not be appropriate in humid climates. If the indoor air exceeds 
60% relative humidity or simply feels uncomfortably humid, it is 
recommended that the fan only be used in the 

AUTO

 mode. The fan 

switch ON position provides continuous operation while the AUTO 
position provides operation during the heating or cooling cycles.

Heating Cycle

Thermostat call for heat ( 2-stage thermostat)
Call for 1st stage only:

(R) and (W1) thermostat contacts close signaling the control 
module (IGN) to run its self-check routine. After the control has 
verified that the pres sure switch (PS) contacts are open, the 
limit switch (TCO) contacts are closed, and the flame rollout (FL) 
switch is closed, the induced draft blower (CBM) will be energized 
on high speed for approximately 5 seconds.
After the induced draft blower (CBM) has come up to speed, 
the control will verify that the pressure switch (PS) contacts are 
closed and switch the induced draft blower to low speed for 20 
second prepurge.  The gas valve (GV) is ener gized   in  the  first 
stage to permit gas flow and the spark igniter (IP) is energized. 
The flame detector (FD) confirms that igni tion has been achieved 
within the 7 second trial period.
As the flame detector confirms that ignition has been achieved 
the delay to indoor fan on period begins timing and after 
approximately 45 seconds, the indoor blower motor (IDM) will 
be energized at low speed and will continue to run during the 
heating cycle.

Call for 2nd stage after 1st stage:

(R) and (W2) thermostat contacts close signaling a call for 
second stage heat. The induced draft motor (CBM) is energized 
on high speed and the gas valve on second stage. After 
approximately 30 seconds the control energizes the indoor 
blower on high speed.

2nd stage satisfied, 1st stage still called:

(R) and (W2) opens, the induced draft blower is reduced to low 
speed the gas valve is reduced to first stage. After about 30 
seconds the indoor blower motor is reduced to low speed. 

1st stage satisfied:

(R) and (W1) opens, the gas valve (GV) will close. The induced 
draft blower (CBM) will be de-energized after approximately 5 
seconds postpurge. The indoor blower motor (IDM) will continue 
to run for the fan off period (field selectable 60 or 90 seconds [by 
jumpers]), then will be de-energized by the control module.

Thermostat call for heat (1-stage Thermostat)

(R) and (W1/W2) (jumped) thermostat contacts close signaling a 
call for heat.  1st stage sequence of operation remains the same 
as above.  2nd stage heat has a 10 minute delay from the time of 
1st stage ignition.

Thermostat satisfied:

(R) and (W1/W2) (jumped) contacts open signaling the control 
module to close the gas valve and de-energize the induced 
draft blower after approximately 5 second postpurge. The indoor 
blower motor will continue to operate at the current speed for 60 
or 90 seconds after the flames are extinguished.

Sequence of Operation

Safety Sequences

This product is equipped with safety devices to protect against 
abnormal conditions.
The temperature limit switch (TCO) is located on the blower barrier, 
and can be accessed through the blower compartment. This automatic 
reset device protects against exces sive supply air temperature. If 
this device opens, the gas valve is immediately closed and will not 
permit operation until the limit switch closes. 
The rollout switch (RO) is located in the gas compartment near the 
inlet of the burners. This is a manual reset device designed to protect 
against any form of flame rollout. If this device is opened the gas 
valve is immediately de-energized and the control (IGN) will lockout 
the system. The rollout switch (RO) must be reset before operation 
is allowed to continue.
The pressure switch (PS) is located in the upper right side of the 
gas compartment. This automatic device assures adequate combus-
tion air pressure. If pressure against the induced draft blower outlet 
becomes excessive, the pressure switch will react and shut off the 
gas valve, until acceptable combustion pressure is again available.
If the control (IGN) does not sense flame within the first trial for igni-
tion period, the gas valve will be de-energized. The control (IGN) 
will initiate a 60-second interpurge. Following the interpurge, the 
control will perform a second ignition attempt. If the second try is 
not successful, the control will start another 60-second interpurge. 
After the interpurge,  a third attempt will be tried. If the third try is 
not successful, the control will lock out.
If loss of flame occurs during a heating cycle, the control (IGN) will 
close the gas valve and cycle through the ignition trial as stated above.
If control lock out occurs, the control (IGN) will retry a complete 
ignition sequence in 1 hour.
The control (IGN) can be reset by removing power to the unit or 
by turning the thermo stat from ON to OFF for approximately three 
seconds, then back ON.

Cooling Cycle

Thermostat call for cooling (2-stage thermostat)
Call for 1

st

 stage cooling only:

 With the room thermostat set to the 

COOL

 position and the fan 

switch in the 

AUTO

 position, a call for cooling will supply power 

to the unit from the room thermostat (Y1) and (G) terminal. 
(Y1) provides power to the compressor contactor (CC). The 
energized compressor contactor (CC) completes the circuit to the 
compressor for 1

st

 stage (Low) operation and the outdoor single 

speed fan motor (ODM).  (G) provides power to the (ECMC) for 
low speed (IDM) indoor fan motor operation.
 
The thermostat will continue to cycle the compressor and fans to 
maintain the desired temperature.

Call for 2

nd

 stage after 1st stage

On a call for 2nd stage cooling, power is supplied from the room 
thermostat (Y2) terminal to the compressor rectifier (ACR) and 
the (ECMC). This energizes the (ACR) switching the compressor 
to 2

nd

 stage (High) operation. With the compressor’s internal 

solenoid energized, both unloading orifices are closed enabling 
the compressor to pump at full rated capacity. The (ECMC) is 
energized for indoor fan motor (ECM) high speed fan operation. 
The room thermostat will continue to cycle the system between 
1

st

 and 2

nd

 stage to maintain the desired temperature without any 

cycling time delays in operation.

Summary of Contents for 4YCZ6024

Page 1: ...ures on the fan Operating the unit without the access panels properly installed may result in severe personal injury or death WARNING SAFETY HAZARD This information is for use by individuals having adequate backgrounds of electrical and mechanical experience Any attempttorepairacentralairconditioningproductmayresult inpersonalinjuryand orpropertydamage Themanufacturer or seller cannot be responsib...

Page 2: ...R 410A operating pressure exceeds the limit of R 22 Proper service equipment is required Failure to use proper service tools may result in equipment damage or personal injury SERVICE Use only R 410A Refrigerant and approved POE compres sor oil IMPORTANT Wear appropriate gloves arm sleeve protectors and eye protection when servicing or maintaining this equipment PRECAUTIONARY MEASURES Avoid breathi...

Page 3: ...g 16 Gas Piping Installation 16 Pipe Delivery Schedule natural gas only 17 Gas Pressure Set up Precautions 17 Gas Supply Line Pressure all fuels 17 Verify Manifold Pressure 18 Input Check and Adjustment 18 High Altitude Installation 19 Air Filter Installation 19 Electrical Wiring 19 Electrical Connections 18 Electrical Power 19 Disconnect Switch 19 Over current Protection 19 Power Wiring 19 Contro...

Page 4: ... Determine Unit Clearances Figure 1 4YCZ6024 6036 1 of 3 Figures 1 through 6 show the unit critical dimensions DWG NO D673947G01_REVC NOTE The view labeled Bottom Side represents the Base as viewed looking up from underneath the unit ...

Page 5: ...Page 5 Installer s Guide Figure 2 4YCZ6024 6036 2 of 3 ...

Page 6: ...uide Step 2 Determine Unit Clearances Figure 1 4YCZ6024 6036 3 of 3 Figures 1 through 6 show the unit critical dimensions NOTE The view labeled Bottom Side represents the Base as viewed looking up from underneath the unit ...

Page 7: ...Page 7 Installer s Guide Figure 4 4YCZ6048 through 4YCZ6060 1 of 3 NOTE The view labeled Bottom Side represents the Base as viewed looking up from underneath the unit ...

Page 8: ...Page 8 Installer s Guide Figure 5 4YCZ6048 through 4YCZ6060 2 of 3 ...

Page 9: ...Page 9 Installer s Guide Figure 6 4YCZ6048 through 4YCZ6060 3 of 3 ...

Page 10: ...r to the Installation section for instruction on converting the supply and return airflow covers to down airflow 3 The field assembled Roof Mounting Curb BAYCURB050A or BAYCURB051A or a field fabricated curb should be in place before the unit is hoisted to the roof top The Roof Mounting Curb frame must be installed on a flat level section of the roof maximum of 1 4 per foot pitch and provide a lev...

Page 11: ...clearance to combustible mate rial shall be maintained on air outlet duct Rooftop Installation Curb Mounting Convert Horizontal Airflow to Down Airflow The factory ships the unit for horizontal airflow Perform this procedure to convert the unit to down airflow 1 Remove the three 3 sheet metal screws securing the supply aircover and the four 4 sheet metal screws securing the return air cover from t...

Page 12: ...tabs or flanges Failure to observe these warnings may result in equipment damage 1 Before preparing the unit for lifting check the unit dimension drawings for center of gravity for lifting safety Figures 1 to 6 page 4 9 Because of placement of internal components the unit s weight may be unevenly distributed Approximate unit weights are also provided in the unit drawings NOTE When unit rigging and...

Page 13: ... roof top applications using field fabricated ducts and sleeper rails rather than a curb or frame use the following procedure 1 Locate and secure the sleeper rails to the roof Three 3 sleeper rails are required One on each end to support the edges of the unit and one across the center of the unit The center rail must run inside both drip lips Vibration isolators should be installed as indicated on...

Page 14: ...sible for the unauthorized use of this drawing and expressly disclaims any liability for damages resulting from such unauthorized use Gasket Seal Spreader Bars Base of unit rest on top of curb rails Drip lip on perimeter of unit Top shipping skid attached to unit IMPORTANT To prevent damage to the sides and top of the unit when hoisting retain the top shipping skid on the unit or use spreader bars...

Page 15: ...orizontal Airflow Application with Frame Supply Air Return Air Roof Flashing Channel Iron Center Support Center Sup port required on all Frame Applications Angle Iron Frame Roof Flashing Return Air Angle Iron Frame Roof Flashing Supply Air Channel Iron Center Support Center Support required on all Frame Applications ...

Page 16: ...oise and vibration transmission Elbows with turning vanes or splitters are recommended to minimize air noise and resistance The first elbow in the ductwork leaving the unit should be no closer than two 2 feet from the unit to minimize noise and resistance To prevent leaking do not attach the ductwork to the bottom of the unit base refer to the bottom example in Figure 14 A 3 4 inch female NPT cond...

Page 17: ...e making the gas pipe connection give serious consideration to providing the clearance necessary to remove the accesspanelsontheunit e g economizerandfilteraccesspanels NOTE In the absence of local codes the installation must con form with American National Standard Z223 1 National Fuel Gas Code Latest Revision The available gas supply must agree with the required gas supply marked on the unit nam...

Page 18: ...nchonthegasvalveinletboss connect the gas piping to the unit Check the completed piping for leaks using a soap and water solution or the equivalent 6 After installation of the gas pipe in the unit the pipe opening should be closed with the filler barrier plug provided Manifold Pressure Check the manifold pressure at the unit gas valve Do not exceed the recommended pressure shown on the unit namepl...

Page 19: ...hat require 49 orifices for altitudes from 7000 8000 orifices must be changed to 50 HIGH ALTITUDE DERATE CHART NAT Altitude In Feet Inputs shown are with factory orifices 3 5 WC High Fire 1 8 WC Low Fire Natural Gas heating value of 950 btu cuft Electrical Power It is important that proper electrical power be available for the unit Voltage variation should remain within the limits found on the uni...

Page 20: ...itioning systems been checked at the service ports for charge and leak tested if necessary Does the condenser fan and indoor blower turn free without rub bing and are they tight on the shafts Has the indoor blower speed been determined and the proper speed been set See the Unit Wiring Diagram Has all work been done in accordance with applicable local and national codes Are all covers and access pa...

Page 21: ...Page 21 Installer s Guide Figure 22 4YCZ6 Field Wiring Diagram NOTE For economizer wiring instructions see the Installer s Guide that came with your economizer ...

Page 22: ...cooling setpoint to above room temperature Heating Cycle Theseunitsareequippedwithasolid stateignitioncontrolthatlights the burners each time the thermostat calls for heat The burners are extinguished during the OFF cycle The gas heating section of the unit can be started using the follow ing procedure 1 Be sure the thermostat is at its lowest setting and the power to the unit is off a Turn the ma...

Page 23: ...ond postpurge The indoor blower motor will continue to operate at the current speed for 60 or 90 seconds after the flames are extinguished Sequence of Operation Safety Sequences This product is equipped with safety devices to protect against abnormal conditions The temperature limit switch TCO is located on the blower barrier andcanbeaccessedthroughtheblowercompartment Thisautomatic reset device p...

Page 24: ... damage Do not store combustible materials gasoline or other flammable vapors or liquids near the unit WARNING Someoftheperiodicmaintenancefunctionsofthe4YCZ6unitcan beperformedbytheowner thisincludesreplacingthedisposable or cleaning the permanent air filters cleaning the unit cabinet and conducting a general unit inspection on a regular basis Filters When the system is in constant operation insp...

Page 25: ... Hood and Combustion Blower Cleaning Manifold Pressure Check and Adjust 1 Connect a manometer to the pressure tap at the outlet side of the unit s gas valve remove the Control Heat access panel Read the manifold pressure with the burners firing See Figure 16 on page 17 for gas valve connections 2 If the manifold pressure reading does not match the value indicated on the unit s nameplate the unit s...

Page 26: ... 3 Flashes Pressure switch problem detected Fast Flash Rate Not used 4 Flashes High Limit switch protection device open Steady ON Normal No Call for Heat 5 Flashes Flame sensed and gas valve not energized or flame sensed and no W signal 6 Flashes Flame Rollout Switch open 7 Flashes Thermostat miswired W1 W2 Fast Flash Rate The LED will flash on for 1 4 second and off for 1 4 second Slow Flash Rate...

Page 27: ...Page 27 Installer s Guide ...

Page 28: ...uide Trane 6200 Troup Highway Tyler TX 75707 9010 The manufacturer has a policy of continuous product and product data improvement and it reserves the right to change design and specification without notice 2017 Trane 09 18 ...

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