Danfoss VLT HVAC Drive FC 102
Danfoss VLT HVAC Drive FC 102 code 18: Start failed
The drive fails to start because the motor speed could not reach the required minimum RPM within the allowed time.
- Code
- 18
- Name
- Start failed
- Controller
- Danfoss VLT HVAC Drive FC 102
- Type
- Motor overload
- What it does
- Fault: the equipment trips and stops
- Risk
- YELLOW Booth plays by its own rules
- Source
- The manufacturer's manual (subscribers see which manual and page)
Updated November 4, 2026
How to fix it
Subscribers get:
- What to do next, in plain words
- Which manufacturer manual it comes from, linked
- The 1 common cause 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 Danfoss VLT HVAC Drive FC 102 code 18 mean?
The drive fails to start because the motor speed could not reach the required minimum RPM within the allowed time.
Is Danfoss VLT HVAC Drive FC 102 code 18 dangerous?
It is graded yellow: not hard, but a booth does it differently than the gear most techs know, so follow the checks in order.
How do I fix Danfoss VLT HVAC Drive FC 102 code 18?
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 Danfoss VLT HVAC Drive FC 102 codes
14 · Ground fault15 · Hardware mismatch16 · Short-circuit17 · Control word timeout23 · Internal fan fault24 · External fan fault25 · Brake resistor short-circuit26 · Brake resistor power limit27 · Brake chopper fault28 · Brake check failed
All 73 Danfoss VLT HVAC Drive FC 102 codes · Every fault code