Riello RS/E BLU Burner Control (REC 27.100A2 with RDI21 display)
Riello RS/E BLU Burner Control (REC 27.100A2 with RDI21 display) code c: 93: c: 93 (with d: 3)
The burner locks out because there is a flame signal acquisition error caused by a short circuit in the sensor.
Safety first. This code involves a gas, flame or electrical hazard. Do not keep resetting it. Leave burner, gas train and high voltage work to a qualified technician. WERCS answers 24/7 at (877) 489-3727.
- Code
- c: 93
- Name
- c: 93 (with d: 3)
- Controller
- Riello RS/E BLU Burner Control (REC 27.100A2 with RDI21 display)
- Type
- Sensor fault
- What it does
- Lockout: the control shuts down and stays off until it is reset
- Risk
- RED Specialist territory
- Reset
- Needs a manual reset
- Source
- The manufacturer's manual (subscribers see which manual and page)
Updated July 23, 2026
How to fix it
Subscribers get:
- What to do next, in plain words
- Which manufacturer manual it comes from, linked
- The 2 common causes listed for this code
- The step by step check for this problem, one check at a time
- Booking a live video call with Ben, a master booth technician ($250/hr, paid per call)
Questions about this code
What does Riello RS/E BLU Burner Control (REC 27.100A2 with RDI21 display) code c: 93 mean?
The burner locks out because there is a flame signal acquisition error caused by a short circuit in the sensor.
Is Riello RS/E BLU Burner Control (REC 27.100A2 with RDI21 display) code c: 93 dangerous?
It is graded red, specialist territory: it involves a burner, gas, flame or safety lockout, so leave the repair to a qualified technician.
How do I fix Riello RS/E BLU Burner Control (REC 27.100A2 with RDI21 display) code c: 93?
The manual's fix and the step by step check for this code are in WERCS Diagnose, plans from $49 a month. For help right now, WERCS answers 24/7 at (877) 489-3727.
Other Riello RS/E BLU Burner Control (REC 27.100A2 with RDI21 display) codes
c: 60 · c: 60 (d: 0)c: 70 · c: 70 (with d: 23 / d: 26)c: 71 · c: 71 (with d: 0/1/2/3)c: 85 · c: 85 (with d: 0 / d: 1)c: 95 · c: 95 (with d: 3/4/5/6)c: 96 · c: 96 (with d: 3/4/5/6)No Comm · No Commc: 50 to 58 · c: 50 to c: 58c: 86 / c: 87 · c: 86 (fuel servomotor) / c: 87 (air ser
All 24 Riello RS/E BLU Burner Control (REC 27.100A2 with RDI21 display) codes · Every fault code