Lennox ML180UHE - User Manual

Page 1
Addendum to Installation Instructions For ML180UHE,
ML180DFE, ML193UHE, ML193DFE, ML196UHE & ML196DFE
508141-01
01/2021
ADDENDUM
This document supersedes any similar/conflicting
instructions found in this bag assembly.
Application
This furnace is designed for single stage heating and
single stage cooling/heat pump application only.
Although equipped with two stage ignition control, wiring
on this unit is strictly configured for single stage
application. Unless allowed by this document, do not
change wiring connections and never cut 2 stage
compressor jumper W915 on the ignition control.
Indoor Blower Speeds (Diagram Figure 1)
For heating operation, control uses indoor blower motor
speed tap connected to “Low Heat” terminal on the
ignition control. See table 2 for allowable heating speed
taps to meet DOE requirements for Fan Energy Rating
and OEM recommended temperature rise range.
Speed tap connected to “high heat” terminal is used for
heating operation only if control finds indoor blower motor
already running when heat is called upon. Therefore,
there must always be an allowable heating motor speed
tap connected to the “High Heat” terminal of the ignition
control.
For Cooling/Heat Pump operation, control uses indoor
blower motor speed tap connected to the “High Cool”
terminal
.
Indoor blower motor speed tap connected to “Low Cool”
terminal is used only for continuous air. Control energizes
“Low Cool” terminal for continuous air only when dip
switches are appropriately set to do so (6 “OFF”, & 7
“ON”).
In order to meet DOE issued July 2019 indoor blower
requirements to meet Fan Energy Ratings, following
motor speed taps must be connected to "Low Cool"
terminal located on Ignition Control. Additionally, per table
7, Dip Switch 6 located on Ignition Control must be in
"OFF" and Dip Switch 7 must be in "ON" position. See
table 1 for speed tap allowed for continuous air.
TABLE 1
Units Model
Allowed Continuous Air
Speed Tap
ML180UHE All Red
ML180DFE All Red
ML193UHE All Red
ML193DFE All Red
ML196UHE All Red
ML196DFE All Red
On-Board Links and Diagnostic Push
Button (Figure 2)
On-Board Link W914 Dehum - DO NOT CUT
On-board link W914, the connection between R & DS,
must NOT be cut, as this furnace is strictly designed for 1
stage compressor application only and is NOT designed
to operate in dehumidification mode
.
On-Board Link W951 Heat Pump (R to O)
On-board link W951 is a clippable connection between
terminals R and O on the integrated control. W951 must
be cut when the furnace is installed in applications which
include a heat pump unit and a thermostat which features
dual fuel use. If the link is left intact, terminal “O” will
remain energized eliminating the HEAT MODE in the heat
pump.
On-Board Link W915 2 Stage Compr (Y1 to Y2)
[ DO NOT CUT]
On-board link W915 is a connection between terminals
Y1 and Y2 on the integrated control. W915 must NOT be
cut, as this furnace is strictly designed for 1 stage
compressor application.

Summary

Application and Blower Speed Settings

On-Board Link Configuration

Explains critical on-board links (W914, W951, W915) for unit operation.

Wiring Diagrams and Control Connections

Integrated Control Terminal Identification

Identifies key terminals and connections on the integrated control board.

On-Board Link Identification on Diagram

Integrated Ignition Control Details

Integrated Control Terminal Layout

Thermostat Connection Terminals (TB1)

On-Board Link Configuration Points

Identifies specific on-board links for system configuration.

Diagnostic Information and Error Codes

Diagnostic LED and Push Button Functions

Describes the operation of the diagnostic LED and push button.

Diagnostic Modes (Error Recall, Flame Signal)

How to access and use error code recall and flame signal modes.

Common Diagnostic Error Codes (E110-E115)

Troubleshooting Specific Errors

Control and Rollout Circuit Errors (E125, E200)

Gas Valve and Pressure Switch Errors (E204, E205, E223, E224)

Limit Switch Circuit Error (E250)

Soft Lockout Error Codes

Flame Sensing and Gas Flow Errors (E270, E273)

Pressure Switch and Limit Circuit Errors (E271, E272, E274)

Integrated Control DIP Switch Settings

Thermostat and Stage Delay Settings (SW1, SW2)

Configuration of SW1 for thermostat type and SW2 for stage delay.

Integrated Control Configuration Guide

DIP Switch Configuration Summary

On-Board Link Wiring Configuration

Visual guide to cutting on-board links for compressor stages and heat pump.

Overview

1. Function Description
2. Indoor Blower Speeds
3. On-Board Links and Diagnostic Push Button
4. Integrated Ignition Control
5. DIP Switch Settings
6. Diagnostic Features
7. Maintenance Features
8. Wiring Connections
9. Important Notes

This document is an addendum to the installation instructions for several Lennox furnace models: ML180UHE, ML180DFE, ML193UHE, ML193DFE, ML196UHE, and ML196DFE. It supersedes any conflicting instructions in the original bag assembly.

Function Description:

These Lennox furnaces are designed for single-stage heating and single-stage cooling/heat pump applications only. Despite being equipped with a two-stage ignition control, the wiring on these units is strictly configured for single-stage operation. This addendum clarifies specific wiring connections and emphasizes that the two-stage compressor jumper W915 on the ignition control must not be cut.

Indoor Blower Speeds:

• Heating Operation: The control utilizes the indoor blower motor speed tap connected to the "Low Heat" terminal on the ignition control. A table (Table 2) provides allowable heating speed taps to meet DOE requirements for Fan Energy Rating and OEM recommended temperature rise range.
• High Heat Operation: If the control detects the indoor blower motor already running when heat is called for, it uses the speed tap connected to the "High Heat" terminal. Therefore, an allowable heating motor speed tap must always be connected to this terminal.
• Cooling/Heat Pump Operation: The control uses the indoor blower motor speed tap connected to the "High Cool" terminal.
• Continuous Air Operation: The indoor blower motor speed tap connected to the "Low Cool" terminal is exclusively for continuous air. The control energizes the "Low Cool" terminal for continuous air only when DIP switches 6 and 7 are set appropriately (6 "OFF", 7 "ON"). To meet DOE July 2019 indoor blower requirements for Fan Energy Ratings, specific motor speed taps must be connected to the "Low Cool" terminal on the Ignition Control. Table 1 specifies the speed tap allowed for continuous air.

On-Board Links and Diagnostic Push Button:

• On-Board Link W914 Dehum (R & DS): This link must not be cut. The furnace is strictly designed for single-stage compressor applications and is not designed to operate in dehumidification mode.
• On-Board Link W951 Heat Pump (R to O): This clippable connection between terminals R and O on the integrated control must be cut when the furnace is installed with a heat pump unit and a thermostat featuring dual fuel use. Leaving it intact will keep terminal "O" energized, eliminating the HEAT MODE in the heat pump.
• On-Board Link W915 2 Stage Compr (Y1 to Y2): This link must not be cut. The furnace is strictly designed for single-stage compressor applications.

Integrated Ignition Control:

The integrated control manages ignition timing, heating mode fan-off delays, and indoor blower speeds based on DIP switch and jumper selections. It includes an internal watchguard feature that automatically resets the ignition control if it locks out. After one hour of continuous thermostat demand for heat, the watchguard will break and remake the thermostat demand to the furnace, automatically resetting the control to relight the furnace.

DIP Switch Settings:

• Switch 1 - Thermostat Selection: This unit must be used with a single-stage thermostat only. The ignition control is factory set with DIP switch 1 in the "OFF" position, and it must remain in this position. This allows the unit to use the motor speed tap connected to the "Low Heat" terminal for heating.
• Switch 2 - Second Stage Delay: This furnace is designed for single-stage heating and cooling only in a heat pump. DIP switch SW2 must be in the "OFF" position. Staged heating is not available on this unit.
• Switches 3 and 4 - Heating Mode Blower-Off Delay: The blower-on delay is fixed at 30 seconds. The blower-off delay (time the blower operates after heating demand is satisfied) can be adjusted using switches 3 and 4. The factory setting is 90 seconds. Adjusting this delay helps achieve a supply air temperature between 90°F and 110°F when the blower de-energizes. Longer delays provide lower supply air temperatures, while shorter delays provide higher supply air temperatures. Table 5 details blower off timings based on switch settings.
  • 60 seconds: Switch 3 ON, Switch 4 OFF
  • 90 seconds (Factory): Switch 3 OFF, Switch 4 OFF
  • 120 seconds: Switch 3 OFF, Switch 4 ON
  • 180 seconds: Switch 3 ON, Switch 4 ON
• Switch 5 - Cooling Mode Blower-Off Delay: The unit is shipped with DIP switch 5 in the OFF position for a 45-second delay. Table 6 details cooling mode off delay settings.
  • 45 seconds (Factory): Switch 5 OFF
  • 2 seconds: Switch 5 ON
• Switches 6 and 7 - Continuous Fan Mode: Continuous fan speed can be controlled by changing DIP switch positions. Table 7 provides DIP switch settings for continuous fan mode, allowing selection for Low Heat, Low Cool, High Heat, and High Cool speeds.
  • Low Heat Speed: Switch 6 OFF, Switch 7 OFF
  • Low Cool Speed: Switch 6 OFF, Switch 7 ON
  • High Heat Speed: Switch 6 ON, Switch 7 OFF
  • High Cool Speed: Switch 6 ON, Switch 7 ON

Diagnostic Features:

• Diagnostic LED: A seven-segment diagnostic LED displays operating status, error codes, and other information. Table 4 lists diagnostic LED codes.
• Diagnostic Push Button: Located next to the LED, this button enables "Error Code Recall" ("E" mode) and "Flame Signal" ("F" mode).
  • Error Code Recall Mode: Press and hold the button to cycle through menu options. Releasing the button selects the displayed item. Select "E" to access the most recent 10 error codes. Select "c" to clear all error codes (requires a second press while "c" is flashing to confirm). A solid "=" indicates exit from this mode.
  • Flame Signal Mode: Select "F" to access this mode, which displays the flame current in microamps (uA). This mode exits after a power reset, pressing and holding the button until three horizontal lines "=" are displayed, or after 10 minutes.

Maintenance Features:

The diagnostic codes (Table 4) provide detailed information on various operational statuses and errors, along with recommended actions to clear and recover. These include:

• E 110 Low line voltage: Check power line voltage and correct.
• E 111 Line voltage polarity reversed: Reverse line power voltage wiring.
• E 112 Ground not detected: Provide proper earth ground.
• E 113 High line voltage: Provide power voltage within proper range.
• E 114 Line voltage frequency out-of-range: Check voltage and line power frequency.
• E 115 Low 24V: Check and correct voltage, consider a larger VA transformer.
• E 117 Poor ground detected (Warning only): Check for proper earth ground.
• E 125 Control failed self-check: Cycle power, replace control if persistent.
• E 200 Hard lockout - Rollout circuit open: Correct cause of rollout trip, replace flame rollout switch.
• E 204 Gas valve mis-wired: Check gas valve operation and wiring.
• E 205 Gas valve control relay contact shorted: Check wiring, replace control if necessary.
• E 207 Hot surface ignitor sensed open: Measure resistance of hot surface ignitor, replace if outside range.
• E 223 Pressure switch failed open: Check pressure, inspect vent and combustion air inducer.
• E 224 Pressure switch failed closed: Check pressure switch operation, inspect vent and combustion air inducer.
• E 227 Pressure switch open during trial for ignition or run mode: Check pressure, inspect vent and combustion air inducer.
• E 229 Ignition occurred with indoor blower operating: Information only.
• E 240 Low flame current - Run mode: Check micro-amperes of flame sensor, clean or replace sensor, measure neutral to ground voltage.
• E 241 Flame sensed out of sequence - Flame still present: Shut off gas, check for gas valve leak.
• E 250 Limit switch circuit open: Check for proper firing rate, blockage, and air flow.
• E 270 Soft lockout - Exceeded maximum number of retries. No flame current sensed: Check gas flow, ignitor lighting, flame sensor current.
• E 271 Soft lockout - Exceeded maximum number of retries. Last retry failed due to the pressure switch opening: Check pressure, inspect vent and combustion air inducer.
• E 272 Soft lockout - Exceeded maximum number of recycles. Last recycle due to the pressure switch opening: Check pressure switch operation, inspect vent and combustion air inducer.
• E 273 Soft lockout - Exceeded maximum number of recycles. Last recycle due to flame failure: Check micro-amperes of flame sensor, clean or replace sensor, measure neutral to ground voltage.
• E 274 Soft lockout - Exceeded maximum number of recycles. Last recycle failed due to the limit circuit opening or limit remained open longer than 3 minutes: Shut down system, check firing rate and air flow, check for blockage.
• E 275 Soft lockout - Flame sensed out of sequence. Flame signal is gone: Shut off gas, check for gas valve leak.
• E 290 Ignitor circuit fault - Failed ignitor or triggering circuitry: Measure resistance of hot surface ignitor, replace if outside specifications.

Wiring Connections:

Wiring diagrams are provided for ML180UHE, ML193UHE, ML193DFE, ML196UHE, ML196DFE (Figure 1) and ML180DFE (Figure 2). These diagrams illustrate connections for the outdoor unit, humidifier, gas valve, ignitor, flame sensor, pressure switches, indoor blower motor, and the integrated control. They also detail the terminal board connections for the thermostat and other components.

Important Notes:

• Use copper conductors only.
• DH and L terminals are not used.
• Do not use speed tap(s) for heating if it results in a temperature outside the rise range.
• For dual fuel single-stage heat pump applications, connect W1 to W1 ONLY if using defrost tempering kit 67M41.
• Do NOT make a wire connection between the room thermostat L terminal and the L terminal of the integrated control.

Lennox ML180UHE Specifications