Keedian — SOP · David's Bridal — Controller Offline (XL10 Controller Failure)

Trigger, action plan, and escalation criteria.

ad_hoc_client Client: David's Bridal hvac high managed tier AI: hybrid

Value drivers

Customer experience Asset lifespan Avoided truck rolls

Preconditions

EMS / WEBs access; ohmmeter on-site; Drop Stat available for temporary installation.

Human role

EMS technician / service technician verifies the XL10 outputs and wiring continuity, then installs a Drop Stat if XL10 failure is confirmed so the unit is left operational.

Action plan

(1) Check EMS/WEBs monitoring — if Setpoint and Space Temperature both read 256, the XL10 has likely failed (it can still appear to work in programming tools). (2) Monitor the site via WEBs while initiating a call for two stages of cooling or heating; adjust setpoints to test the correct mode. (3) At the EMS panel terminal strip, remove R, Y1, Y2 (cooling) or W1, W2 (heating) from the field-wiring side (not the panel supply side, directly from XL10 board terminals); ohmmeter-test R to Y1/Y2 (or W1/W2) for contact closure — open contacts suggest XL10 fault. (4) Check for wiring shorts: disconnect Y1/Y2 (or W1/W2) at both ends; ohmmeter between the two wires. (5) Test continuity on the EMS terminal strip itself — closed contacts there mean the XL10 is likely faulty; open contacts mean the XL10 is likely OK and the issue is elsewhere. (6) Final checks: if voltage confirms a call for cooling/heating at the unit and EMS terminal strip contacts are closed, the XL10 is likely not the issue; if wiring looks clean, suspect mechanical. (7) If XL10 failure is confirmed, do not leave the unit down — install a Drop Stat (Temporary Construction Stat) until permanent repairs are completed.

Author

Dylan Turman

Tools

EMS / WEBs Ohmmeter XL10 Controller Drop Stat (Temporary Construction Stat)

Roles

EMS Technician Service Technician Monitoring Personnel

Purpose

Identify, verify, and remediate suspected XL10 controller failures at David's Bridal — install a temporary control (drop stat) so the HVAC unit remains operational until the permanent fix.

Scope

EMS technicians, service technicians, and monitoring personnel supporting David's Bridal locations with XL10 controllers.

Procedure

Step 1 — Identify Possible XL10 Failure

Check EMS/WEBs for abnormal readings.
If Setpoint and Space Temperature both read 256, the controller has likely failed.
The XL10 may appear to function in programming tools while still failing to control the HVAC unit.

Step 2 — Confirm HVAC Call from the XL10

Monitor the site via WEBs while initiating a call for two stages of cooling or heating.
Adjust setpoints if necessary so the correct operating mode is being tested.

Step 3 — Verify Call for Cooling or Heating

Remove R, Y1, and Y2 (or W1 and W2 for heating) from the EMS panel terminal strip.
Remove wires from the field-wiring side, not the panel supply side (directly from the XL10 board terminals).
Use an ohmmeter to check contact closure between R and Y1 (or W1) and between R and Y2 (or W2).
If contacts show open, the XL10 controller is likely faulty.

Step 4 — Check for Wiring Shorts

Disconnect Y1 and Y2 (or W1 and W2) wires from both ends.
Check for direct shorts between these wires.
If Y1/Y2 remain open, inspect the EMS terminal strip and test continuity between the Y1/Y2 (or W1/W2) terminals.
Closed contacts on the strip → XL10 likely faulty. Open terminals → XL10 likely functioning correctly.

Step 5 — Perform Final System Checks

If voltage confirms a call for cooling/heating at the HVAC unit and the EMS terminal strip contacts are closed, the XL10 is likely not the issue.
If wiring tests show no damage or open circuits, perform additional troubleshooting on the HVAC unit (likely mechanical, not EMS).

Step 6 — Install Temporary Control if XL10 Failure is Confirmed

Do not leave the unit down.
Install a Drop Stat (Temporary Construction Stat) to keep the HVAC unit running until permanent repairs.

Quality assurance

Verify Setpoint and Space Temperature readings in EMS monitoring.
Confirm proper voltage calls for heating or cooling at the HVAC unit.
Ensure the Drop Stat is installed if the XL10 controller has failed.
Document all troubleshooting steps and results.

Troubleshooting

Controller shows a call but the unit does not run.

Solution. Verify XL10 outputs via ohmmeter between R and Y1/Y2 (or W1/W2); confirm the HVAC unit receives the call signal.

Suspected wiring or terminal-strip fault.

Solution. Disconnect wires and check for shorts or continuity issues between Y1/Y2 or W1/W2; inspect the EMS terminal strip to confirm whether contacts are open or closed.

Documentation & reporting

Record all troubleshooting steps, voltage readings, and continuity tests in the work order (WO).
Document confirmation of XL10 controller failure, if applicable.
Record the Drop Stat installation and confirm the unit was left operational.
Reference the XL Troubleshooting Tab for additional guidance if needed.

Revision history

Version	Date	Author	Changes
`1.0`	03/11/2026	Dylan Turman	Initial draft.

David's Bridal — Controller Offline (XL10 Controller Failure).