What It Means
- Open pressure switch (heat pump systems only)
Lennox Zone controller
Lennox Error Code 1001
Zone controller
Causes & actions from Lennox
How it shows
- harmony diagnostic led1234: 1001 (led1: on, led2: off, led3: off, led4: on)
Displayed when the pressure switch opens and does not necessarily mean there is anything wrong. However, try increasing the air delivered to the smallest zone. An open pressure switch will stage the heat pump down to 1st stage only, if after 90 seconds the switch does not close, the heat pump is shut off and backup heat is used to satisfy the call. Green Pressure switch LED on zone panel will be off.
Applicable models & manual sources
- HARMONY III
Open pressure switch (heat pump systems only)
HARMONY III, X9953
Disclaimer: This information is for general reference. Code wording and instructions vary by model. Always follow the service manual for your exact unit.
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