IQ Relay LED1 (voltage) is green but LED2 (frequency/DCI) is solid red — grid frequency is outside the permitted reconnection window.
Common causes
Grid frequency excursion (outside 47–52Hz for standard UK G98)G99 frequency response settings incorrectly set
What to check
STEP 1
Check grid frequency with a power quality meter. If frequency has normalised, relay should reconnect automatically after the hold-off period (typically 20 seconds)
STEP 2
Check G98/G99 frequency response settings in Installer Toolkit. Verify frequency thresholds match the DNO approval for the site
Escalate if
Grid frequency is confirmed within 47–52Hz but relay remains open — relay hardware or firmware fault, escalate
Need full interactive diagnosis?
Faultpath walks you through decision trees, fault codes, and commissioning — built for solar & battery engineers.