SCHV / SDHV Ducted – P7 Fault (Quick Diagnostic Guide)

Applies to:
Braemar SCHV (Outdoor) + SDHV (Indoor) Ducted Reverse‑Cycle Systems
Where displayed: XE71, XK60, XK75 controllers or outdoor PCB fault indication.

What P7 Means

P7 = Outdoor unit is overheating, or the system thinks it’s overheating.
This protection is built into the inverter to prevent compressor or driver/module damage.

  • Overheating commonly comes from blocked condenser coils, poor outdoor airflow, or weak outdoor fan performance.
  • It can also be triggered by a faulty temperature sensor, incorrect sensor reading, or an overheating power/driver module.
  • The Braemar service guide places P‑series errors under ducted split diagnostics in Error Codes for Ducted Split Systems (Section 35).

1. Quick Checks (Fix 90% of P7 Faults)

A. Outdoor Unit Airflow & Coil Condition

  1. Check the condenser coil for dirt, fluff, leaves or grass.
    • A dirty coil dramatically increases discharge temperature.
  2. Ensure the outdoor fan spins strongly and ramps up properly.
    • Wrong speed or weak airflow leads to overheating.
  3. Confirm the outdoor unit has clear air around it.
    • No hot‑air recirculation, blocked fences, or stacked items behind it.

B. Temperature Sensor Checks

  1. Locate the temperature probe clipped onto the discharge pipe.
  2. Make sure it is firmly attached, insulation intact, and wiring is not damaged.
  3. A loose or faulty sensor can create false high readings.
  4. Sensor resistance can be confirmed using the Resistance Table (Section 36) in the service guide.

C. Refrigerant Condition (Simple Field Indicators)

Without gauges, look for:

  • Frosting or hissing on pipework
  • Very hot discharge pipe temperature
  • Short cycling or hard compressor starts

These are indicators of possible under‑charge or restriction, which increases discharge temperature and triggers P7.

D. Electronics Overheating (Driver/IPM Module)

If coils and airflow are fine:

  • Check outdoor PCB for darkened components, burn marks, or insect contamination.
  • Poor airflow across the PCB can cause driver/IPM overheating, which is known on inverter platforms to activate P‑series protections.

2. Quick Step‑by‑Step Troubleshooting

Step 1 — Start with the Outdoor Unit

  • Clean coil thoroughly
  • Confirm fan operation & strong airflow
  • Ensure outdoor unit is not boxed‑in

If issue persists → Step 2

Step 2 — Check the Sensor

  • Ensure discharge sensor is clipped firmly
  • Check wiring back to PCB
  • Replace if visibly damaged

If issue persists → Step 3

Step 3 — Look for Refrigerant Symptoms

  • Frosting, very hot discharge line, strange compressor sounds
  • If suspicious → perform full pressure/temperature test

If issue persists → Step 4

Step 4 — Inspect Electronics

  • Remove outdoor cover
  • Check PCB for signs of overheating or damage
  • Confirm airflow over PCB (some models cool the board through the condenser fan stream)

3. When to Escalate

Perform a full system diagnosis if:

  • P7 returns immediately after cleaning coil and confirming strong airflow
  • Sensor tests correctly using the Resistance Table (Section 36)
  • Outdoor location has adequate ventilation
  • No signs of refrigerant issues are present

At this point, suspect:

  • Driver/IPM thermal fault
  • Outdoor main PCB failure

4. Summary for Technicians

P7 = Outdoor unit too hot OR sensor reading that it’s too hot.
Fix order:
1) Coil & airflow → 2) Sensor → 3) Refrigerant → 4) PCB/Driver module

This ordering solves most P7 faults efficiently and avoids unnecessary component replacement.