High-limit output relay is not closed when it should be. The service facts say 24 VAC was not sensed on HLO ten times.
Likely causes
- 24 VAC not sensed on the high-limit output (HLO) ten times
Safe checks for E2.4
- Write down E2.4. This row is the control's high-limit output relay, not an open temperature limit
- Technicianthe troubleshooting step for fault 2.4 is to replace the integrated furnace control
Capacitors can hold a charge after the power is off. Safety terms.
When to call a pro
Call a licensed HVAC technician. Do not replace the limit switch from this page. The chart's action is to replace the IFC.
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Parts & tools for this fix
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High limit and rollout switches: guide
In this code: 24 VAC not sensed on the high-limit output (HLO) ten times
A safety device: we explain it but do not link to buy one.
Furnace control board and low-voltage fuse: guide
In this code: Parts list for this code: Integrated furnace control
This one is for a technician to test or replace, so we only explain it and do not link to buy it.