Lennox LZP-4 - User Manual

Other manuals for Lennox LZP-4

Installation Instructions28 pages

Questions and Answers

K
Kyle RasmussenAug 19, 2025
Why is my Lennox LZP-4 Control Panel condensing unit receiving a signal but not turning on?
- J
  juanwarnerSep 12, 2025
  If the condensing unit receives a signal but does not turn on, it could be due to several reasons. The pressure switch may be open, the compressor might be off due to an internal overload protector, or the condenser control board's anti-short cycle timer might not have expired yet. Most anti-short cycle timers are 5 minutes or less. If the unit doesn't start after 5 minutes, consult the condensing unit manual for possible causes.
B
brent03Aug 23, 2025
Why is the cooling not working on my Lennox LZP-4?
- T
  Todd RiceAug 25, 2025
  If the cooling won't come on with your Lennox Control Panel, here are some possible causes: * For single transformer systems, install a jumper between RC and RH at the HVAC equipment outputs of the control panel. * Check the voltage at the thermostat Y input on the control panel to ensure the thermostat is calling for cooling. * If using a power-robbing or mechanical thermostat, switch to a line-powered electronic thermostat with a C terminal. * If the zone panel is set up for Zone 1 mode control, verify that the Zone 1 O terminal is energized by checking the ZONE 1/ANY ZONE dip switch and checking for voltage at Zone 1 O terminal. * If an open or short in the DAS sensor has been detected, install or repair the sensor.
J
johnallenAug 26, 2025
What to do if the Lennox Control Panel air handler receives a signal but doesn't turn on?
- Z
  zmcbrideAug 26, 2025
  If the air handler is receiving a signal but will not turn on, it could be due to a limit on the furnace being open. Check the position of the DAS in the plenum and move it further downstream if possible. Another reason could be that the DAS limit jumper needs to be moved to a lower setting.
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jamiediazAug 27, 2025
Why is the fan running but there's no heat and the HEAT LED is blinking on my Lennox LZP-4 Control Panel?
- J
  Julian FitzgeraldAug 27, 2025
  If the fan is running but there is no heat and the HEAT LED is blinking on your Lennox Control Panel, the discharge air temperature likely exceeds the set limit. Allow the discharge air to cool 10° below the set limit and allow the timed-off delay to expire.
S
Susan RogersAug 30, 2025
Why is the fan running but there's no cooling and the COOL LED is blinking on my Lennox LZP-4 Control Panel?
- M
  mdayAug 30, 2025
  If the fan is running but there is no cooling and the COOL LED is blinking on the Lennox Control Panel, it means that the discharge air temperature has dropped below the set limit. Allow the discharge air to warm 10° above the set limit and allow the timed off delay to expire.
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imcdonaldSep 1, 2025
Why won't the emergency heat come on with my Lennox LZP-4 Control Panel?
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  joseph26Sep 1, 2025
  If the emergency heat won't come on with your Lennox Control Panel, make sure that Emergency Heat (E-HEAT SELECTOR) slide switch is set to ON. If heat pump thermostats are used with the zone panel set to ZONE 1 or AUX MINUTES is set to a value other than 0 minutes, and if heat pump thermostats are used in all zones, set AUX MINUTES to 0 and set ZONE 1/ANY ZONE switch to ANY ZONE.
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Billy SuttonSep 3, 2025
What to do if nothing comes on with my Lennox Control Panel?
- A
  Aaron SmithSep 3, 2025
  If the Lennox Control Panel's green “Normal Flashing” LED is not blinking, this indicates that there is no power being supplied to the control panel. Apply power to the 24VAC inputs and check the fuse.
K
Kevin AndersonSep 5, 2025
What to do if the Lennox Control Panel furnace tripped the primary limit, but the zone panel doesn't indicate a discharge air limit issue?
- S
  Susan CraigSep 5, 2025
  If the furnace tripped the primary limit, but the zone panel does not indicate that the discharge air limit has been exceeded, it could be due to a high static condition. In this case, move the sensor further downstream to sense air that has mixed more thoroughly. Another cause may be that the bypass tap is too close to the inlet of the air handler, adjust the bypass tap in the return air duct so that it is further away from the furnace.
M
Matthew BrownSep 7, 2025
Why does the fan immediately come on with a heat call on my Lennox LZP-4?
- P
  patrick25Sep 7, 2025
  If the Lennox Control Panel fan immediately comes on with a heat call, the ELEC/GAS jumper is likely set to ELEC. Change the setting to GAS.
R
Richard MitchellSep 9, 2025
Why aren't the dampers positioning correctly on my Lennox LZP-4?
- M
  Michael JonesSep 9, 2025
  If the dampers do not position on a call for heating, cooling, or fan with your Lennox Control Panel, it might be because the system requires the Discharge Air sensor. Disconnect power to the control panel, install the DAS, and restore power. Another possible cause is that the ZONE 1/ANY ZONE switch is set to ZONE 1. This allows only heat calls when Zone 1 is in heat mode and only cooling calls when Zone 1 is in cool mode.

Summary

Overview

Model LZP-4

Basic Operation

Explains how the LZP-4 system increases comfort by directing conditioned air to separate zones based on thermostat settings.

Heating and Cooling Operation

Heating Operation

Provides step-by-step instructions for initiating a heating call by setting the thermostat to Heat mode and adjusting the set point.

Cooling Operation

Provides step-by-step instructions for initiating a cooling call by setting the thermostat to Cool mode and adjusting the set point.

Advanced System Functions

Emergency Heat Operation

Details the two options for operating Emergency Heat, dependent on thermostat installation and control panel settings.

Damper Operation

Explains how dampers serve calling and non-calling zones and the meaning of zone damper LEDs.

System Controls and Settings

Fan Operation

Describes how the control panel manages fan operation from any zone and the 'Fan On' LED indicator.

Turning the System Off

Outlines the procedure for shutting down the system by setting all thermostats to OFF mode.

Thermostat Replacement

Provides guidance on thermostat replacement, emphasizing compatibility and the need for a 'C' terminal.

Maintenance

Lennox LZP-4 Specifications

General

Brand	Lennox
Model	LZP-4
Category	Control Panel
Language	English