Bosch
E5
LockoutHigh / low voltage protection
Line voltage out of band (IDS: operate ~180–270 V; typical run ≥210 V).
Walk E5 in Diagnose
Sign in for the next measurement
First check
1 Measure at the IFC under load
On Bosch BOVA 2.0 line-voltage codes are incoming power. Measure L1/L2 (or L1/N) at the board while it is trying to run, not just at the disconnect. L1–L2 at the outdoor. A just-pulled disconnect can E5 on the inrush — wait and recheck.
Expect: Voltage in the rating-plate window under load.
The rest of the walkthrough is Diagnose.
On the plates
- L1–L2 at the outdoor. A just-pulled disconnect can E5 on the inrush — wait and recheck.
- This is line voltage, not a 24 V stat brownout. Still verify 18–28 VAC Y–C at the AHU so you do not chase the drive for a dead transformer.
Plates that use E5
Same number, other makers
E5 on Bosch is not the same code on these plates.