Rheem R96VA0702317MSA Error Code 23: HALC Open
What Does Code 23 Mean?
Code 23 appears on the Rheem R96V Integrated Furnace Control (IFC) when the board cannot sense electrical continuity between pins 3 and 5 of connector P1. Those pins would normally be bridged by a High Altitude Limit Control. Gas heating is disabled while cooling and fan modes keep working, because the burners cannot be allowed to fire with a safety-limit circuit reading open.
The important detail for this specific furnace is that it is not fitted with an actual HALC device. In its place, the factory installs a short jumper wire between pins 3 and 5 of connector P1 so the circuit reads closed. The code exists in the IFC's fault list because the same control board is shared across R96V-family models, some of which do carry a physical high-altitude limit. On the R96VA0702317MSA the practical meaning of code 23 is narrow: the jumper wire is no longer making a solid connection between the two pins.
That loss of continuity typically comes from a jumper that has vibrated loose, backed partway out of the connector, corroded, or broken. It can also follow service work where P1 was unplugged and not fully reseated. Because the fix means working at the low-voltage control board and connector, it is a technician repair on this model, not a homeowner task. Reseating or replacing the jumper restores the circuit and clears the code.
What You'll Notice
- The furnace will not produce heat, but cooling and the fan-only setting still run normally
- The IFC display shows a steady 23
- The problem often appears right after the furnace or its control board was serviced or bumped
- The blower may run at heat speed even though the burners never light
- The failure can be intermittent, coming and going as the loose jumper shifts
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Jumper wire between pins 3 and 5 of connector P1 disconnected or broken | Most common | ✗ Call a pro → |
How This Is Diagnosed
A technician confirms the fault by inspecting connector P1 on the IFC and checking for a jumper wire bridging pins 3 and 5. With power safely removed, they look for a jumper that has backed out, broken, or corroded, then verify continuity across those two pins. Because the same board is used on models that carry a real high-altitude limit, they also confirm the furnace is in fact the jumper-equipped configuration before concluding the jumper is the fault rather than an actual limit device.
When to Call a Professional
This code involves components that are not homeowner-serviceable, so have a licensed HVAC technician diagnose and repair it. Keep in mind:
- The furnace shows code 23 and will not heat while cooling still works
- The code appeared right after the control board or its connectors were serviced
- Code 23 comes and goes intermittently, suggesting a jumper that is loose rather than fully broken
- You can see a wire near connector P1 that looks unseated or damaged but are not equipped to work safely at the control board
Frequently Asked Questions
My furnace does not have a high-altitude control, so why do I get a HALC code?
The R96V control board is shared with models that do have a high-altitude limit. On your furnace a jumper wire substitutes for that device, and code 23 simply means the IFC no longer sees continuity across it.
Can I just push the jumper wire back in myself?
The repair is at the low-voltage control board, which is a technician task on this model. A technician can confirm the correct pins, reseat or replace the jumper, and verify continuity so the fix actually holds.
Is code 23 dangerous?
The code itself is the safety system doing its job by refusing to fire the burners when a limit circuit reads open. It is not an emergency, but the furnace will not heat until the jumper connection is restored.
✓ Verified against manufacturer service manual — March 2026