Danfoss VLT HVAC Drive FC 102
Danfoss VLT HVAC Drive FC 102 code 48: 1.8 V supply low
The drive will fault because the internal 1.8-volt DC supply on the control card is outside of allowable limits.
- Code
- 48
- Name
- 1.8 V supply low
- Controller
- Danfoss VLT HVAC Drive FC 102
- Type
- Low voltage
- What it does
- Warning: the equipment keeps running and flags a problem
- Risk
- GREEN In your wheelhouse
- 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
- What the manual says to do, and the page it is on
- 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 Danfoss VLT HVAC Drive FC 102 code 48 mean?
The drive will fault because the internal 1.8-volt DC supply on the control card is outside of allowable limits.
Is Danfoss VLT HVAC Drive FC 102 code 48 dangerous?
It is graded green: in a working tech's wheelhouse with standard tools and low risk.
How do I fix Danfoss VLT HVAC Drive FC 102 code 48?
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
42 · Overload of digital output on X30/6 or o45 · Ground fault 246 · Power card supply47 · 24 V supply low49 · Speed limit50 · AMA calibration failed51 · AMA check Unom and Inom52 · AMA low Inom53 · AMA motor too big54 · AMA motor too small
All 73 Danfoss VLT HVAC Drive FC 102 codes · Every fault code