Dometic · FreshJet FJZ rooftop air conditioners
ELLIN or CI bus communication failure
The rooftop unit has lost communication over its LIN/CI control bus.
What it means
Plain-English answer
EL is a network communication fault between HVAC control components. Dometic directs the code to authorized service.
Owner-safe checks
What to check first
- 01
Record all connected control and thermostat model numbers.
- 02
Turn the HVAC system off and restore normal 12-volt control power once.
- 03
Note whether other connected zones or devices are also offline.
Safety boundary
Stop and call a technician when
- Do not probe or jumper bus wiring while energized.
- The code returns after a normal power cycle.
Primary reference
Check the exact manual
Applicability: FreshJet FJZ rooftop air conditioners. The data plate and specification letter determine which procedure is correct.
Open Dometic FreshJet FJZ operating manual ↗Source reviewed August 2026