Daikin VRV 5 Heat Recovery Aircon CH-21 Error Code
Use this Daikin VRV 5 Heat Recovery CH-21 error code guide to confirm the source table meaning, capture the reporting equipment and model, and match the service manual before diagnosis. Match the model first; same-looking codes can point to different rows.
What does Daikin CH-21 mean?
Daikin VRV 5 Heat Recovery CH-21 is listed as r32 sensor malfunction in a BS unit and r32 sensor malfunction in a SV unit in VRV 5 Heat Recovery REMA / REYA R32 and VRV 5 Heat Pump RYMA / RXYA R32 source rows. The loaded row is source-backed by official diagnostic material. Do not collapse this code across model families; use the model, series, or system type to choose the right row. Confirm the exact model, series, or signal row before accepting a parts quote.
Choose the matching source row
The same visible code has more than one source-backed meaning. Match the model family, system type, or reporting unit before approving parts.
| Code | What it means | What to check first |
|---|---|---|
| VRV 5 Heat Recovery R32 - CH-21 | R32 sensor malfunction in a BS unit | Check the BS-unit R32 sensor connection at the PCB or actuator. |
| VRV 5 Heat Pump R32 - CH-21 | R32 sensor malfunction in a SV unit | Check the SV-unit R32 sensor connection at the PCB or actuator. |
What to do now
Use these steps to record evidence and match the installed model to its service manual before diagnosis or a repair quote.
Record CH-21 and match the service manual
Record CH-21 and stop there; the source table gives no customer reset procedure. Arrange diagnosis with the matching service manual.
No manufacturer reset steps listed for CH-21
Capture the complete CH-21 error code and model stickers first. The source table lists the meaning but no customer reset procedure; do not treat a generic power-cycle as manufacturer guidance.
Send these to us
CH-21 error code, a clear display photo, Daikin VRV 5 Heat Recovery indoor and outdoor model stickers, the controller, gateway, or unit that reported the code, operating mode and affected area, and any power or setting changes made after the code appeared
Source-specific guidance
These diagnostic-reference notes help match the code to the exact model. Electrical, refrigerant, wiring, resistance, and component checks are technician work, not DIY steps.
| Source detail | What it says |
|---|---|
| Singapore / model note | Official Daikin 4P687640-1D row for the REMA5A7Y1B and REYA8~20A7Y1B VRV 5 Heat Recovery R32 family. Confirm the exact model and displayed punctuation before using this interpretation. |
| Singapore / model note | Official Daikin 4P749918-1B row for the RYMA5A7Y1B and RXYA8~20A7Y1B VRV 5 Heat Pump R32 family. Confirm the exact model and displayed punctuation before using this interpretation. |
What to check before repair
The source table establishes the code meaning, not a repair procedure. Capture evidence first; model-specific tests belong to the matching service manual.
| You can check | Technician should confirm |
|---|---|
| Photograph the complete CH-21 error code before taking any action. | Confirm CH-21 exactly and record which controller, gateway, or unit reported it. |
| Capture the Daikin VRV 5 Heat Recovery indoor and outdoor model stickers and identify which controller or unit reported it. | Match the indoor and outdoor model stickers, installed family, and reporting equipment to the source scope. |
| The source table provides no customer reset procedure. Preserve the evidence and use the matching service manual for any system action. | Follow the matching service-manual procedure and keep measured test evidence before naming a failed part. |
Source-bounded repair decision
Daikin VRV 5 Heat Recovery CH-21 confirms the source-table fault label, not a failed part or repair procedure. Match the installed model to its service manual and require measured diagnostic evidence before approving parts, settings, or refrigerant work.
Whether the reporting controller or unit and exact installed model are confirmed.
What the matching service-manual procedure and measured tests show.
Whether the proposed repair names the evidence for the failed part or condition.
Daikin CH-21 questions
What does the Daikin CH-21 error mean?
Can I fix a Daikin CH-21 error myself?
Is it safe to keep running the aircon with a CH-21 error?
What causes a Daikin CH-21 error?
Will a Daikin CH-21 error need a repair or a full replacement?
What should I send a technician about a Daikin CH-21 error?
Confirm the fault
Share the error code, model number and symptoms so we can assess the likely cause.
Not the right code?
Browse the full Daikin list or check a few codes in the same fault category.
Ready to get started?
Tell us what’s going on. Symptoms, setup, photos, anything we should know. We’ll assess and come back with the right next step.
Read next
Use this quote-check guide only after the matching service manual identifies the diagnostic path.