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Fault codes › Solis › Solis S5-GC(75-125)K-US

Solis S5-GC UN-BUS

Code: UN-BUS
Shown as: DC BUS voltage is too low
Page: 69
ID: fc:solis-s5-gc-us-unbus
IRI: https://solarlattice.org/kb/fc/solis-s5-gc-us-unbus
Status: active
Also known as: UN-BUS, unbus, Solis UN-BUS, DC BUS voltage is too low
Category: Inverters

Class fault drafted · lead

Production not stated

Clears needs service verified · fact

Decoded

Reports DC bus undervoltage; look at inverter; confirm with DC voltage measurement; do: inverter restart, inverter replacement.

What can be behind DC bus undervoltage

Failure modes that present as the reported condition, and the tests that tell them apart.

Defined in

Solis Manual S5 (75-100)K US V2,3(20230623) — Ginlong Solis · 2 · page 69 drafted · lead
- tbl=13.r5 h=7868f947bd08

The manufacturer's own cause and corrective text is not reproduced here.

Same condition on other equipment

ABB / FIMER: ABB / FIMER PVS-166-175-TL E010, ABB / FIMER PVS-166-175-TL W011, ABB / FIMER PVS-60-TL E010, ABB / FIMER PVS-60-TL W011, ABB / FIMER TRIO-20.0-27.6-TL E010, ABB / FIMER TRIO-20.0-27.6-TL W011, ABB / FIMER UNO-DM-3.3-5.0-PLUS E010, ABB / FIMER UNO-DM-3.3-5.0-PLUS W011, ABB / FIMER UNO-DM-6.0-PLUS E010, ABB / FIMER UNO-DM-6.0-PLUS W011
CPS: CPS SCA50-100K-T Fault6080
Canadian Solar: Canadian Solar 125K-T600GL02 UN-BUS, Canadian Solar 125KTL-GS-E UN-BUS, Canadian Solar 185-255K UN-BUS01/02, Canadian Solar 25-40K-T480GL01 UN-BUS, Canadian Solar 25-40KTL-GS-FL UN-BUS, Canadian Solar 50-66K-T480GL01 UN-BUS, Canadian Solar 50-66KTL-GS-FL UN-BUS, Canadian Solar 75-100K-T480GL02 UN-BUS
Fronius: Fronius Primo 443, Fronius Symo 443
KACO new energy: KACO new energy blueplanet TL3 84
Solis: Solis 1P-4G-US UN-BUS, Solis 3P-5G-US UN-BUS01/02, Solis RHI-1P-HV UN-BUS01/02, Solis S6-EH1P UN-BUS01/02, Solis S6-EH2P UN-BUS01, Solis S6-EH3P30-60K UN-BUS01, Solis S6-EH3P75-150K UN-BUS01, Solis S6-GC UN-BUS, Solis S6-GU UN-BUS

Same code in other families

Claims

`defined_in`

c1 drafted · lead Solis Manual S5 (75-100)K US V2,3(20230623)

Solis Manual S5 (75-100)K US V2,3(20230623) tbl=13.r5 h=7868f947bd08

`reports`

c2 verified · fact DC bus undervoltage

Solis Manual S5 (75-100)K US V2,3(20230623) tbl=13.r5 h=7868f947bd08
Solis_Manual_S6_GC(25-60)K-US_V1.1(20251013) tbl=12.r5 h=7868f947bd08
Solis S6-GC30K-LV-US Manual V1.2 tbl=11.r5 h=7868f947bd08
Solis S6-GC30K-LV-US Manual V1.2 tbl=14.r1 h=2e74ad175265
Solis_Manual_S6-GU(250-350)K-EHV-USA_PE-MN-0001-R00 tbl=10.r5 h=81c6417ed68c
Solis_Manual_Solis-1P(6-10)K-4G-US_PLUS_V2.1_20250804 tbl=14.r2 h=87b661b382e3
Solis_Manual_(3.6-5)K_4G_PLUS_LW_USA_03212023 tbl=13.r2 h=87b661b382e3

verified by: review-workflowverified on: 2026-10-20

`detected_by`

c3 drafted · lead DC voltage measurement

Solis Manual S5 (75-100)K US V2,3(20230623) tbl=13.r5 h=7868f947bd08
Solis_Manual_S6_GC(25-60)K-US_V1.1(20251013) tbl=12.r5 h=7868f947bd08
Solis S6-GC30K-LV-US Manual V1.2 tbl=11.r5 h=7868f947bd08
Solis S6-GC30K-LV-US Manual V1.2 tbl=14.r1 h=2e74ad175265
Solis_Manual_S6-GU(250-350)K-EHV-USA_PE-MN-0001-R00 tbl=10.r5 h=81c6417ed68c
Solis_Manual_Solis-1P(6-10)K-4G-US_PLUS_V2.1_20250804 tbl=14.r2 h=87b661b382e3
Solis_Manual_(3.6-5)K_4G_PLUS_LW_USA_03212023 tbl=13.r2 h=87b661b382e3

`affects`

c4 drafted · lead Inverter

Internal damage or wire loosened in shipping.

Solis Manual S5 (75-100)K US V2,3(20230623) tbl=13.r5 h=7868f947bd08
Solis_Manual_S6_GC(25-60)K-US_V1.1(20251013) tbl=12.r5 h=7868f947bd08
Solis S6-GC30K-LV-US Manual V1.2 tbl=11.r5 h=7868f947bd08
Solis_Manual_S6-GU(250-350)K-EHV-USA_PE-MN-0001-R00 tbl=10.r5 h=81c6417ed68c
Solis_Manual_Solis-1P(6-10)K-4G-US_PLUS_V2.1_20250804 tbl=14.r2 h=87b661b382e3
Solis_Manual_(3.6-5)K_4G_PLUS_LW_USA_03212023 tbl=13.r2 h=87b661b382e3

`mitigated_by`

c5 drafted · lead Inverter restart

Solis S6-GC30K-LV-US Manual V1.2 tbl=14.r1 h=2e74ad175265

c6 verified · fact Inverter replacement

Solis Manual S5 (75-100)K US V2,3(20230623) tbl=13.r5 h=7868f947bd08
Solis_Manual_S6_GC(25-60)K-US_V1.1(20251013) tbl=12.r5 h=7868f947bd08
Solis S6-GC30K-LV-US Manual V1.2 tbl=11.r5 h=7868f947bd08
Solis S6-GC30K-LV-US Manual V1.2 tbl=14.r1 h=2e74ad175265
Solis_Manual_S6-GU(250-350)K-EHV-USA_PE-MN-0001-R00 tbl=10.r5 h=81c6417ed68c
Solis_Manual_Solis-1P(6-10)K-4G-US_PLUS_V2.1_20250804 tbl=14.r2 h=87b661b382e3
Solis_Manual_(3.6-5)K_4G_PLUS_LW_USA_03212023 tbl=13.r2 h=87b661b382e3

verified by: review-workflowverified on: 2026-10-20

`has_event_class`

c7 drafted · lead Fault (device stops or needs intervention)

Solis_Manual_S6-GU(250-350)K-EHV-USA_PE-MN-0001-R00 tbl=10.r5 h=81c6417ed68c
Solis_Manual_S6-GU(250-350)K-EHV-USA_PE-MN-0001-R00 tbl=10 h=d1948e6b3649
Solis S6-GC30K-LV-US Manual V1.2 tbl=14.r1 h=2e74ad175265
Solis S6-GC30K-LV-US Manual V1.2 tbl=14 h=ea15e4c7ba67

review note: support check: partial - Row says 'DC bus voltage too low for inverter to operate' and suggests restart or replace, implying a stop, but…

`has_recovery`

c8 verified · fact Service required

Internal damage or loose internal wire; replacement after measurements.

Solis Manual S5 (75-100)K US V2,3(20230623) tbl=13.r5 h=7868f947bd08

verified by: review-workflowverified on: 2026-10-20

`applies_to`

c9 drafted · lead Solis S5-GC(75-125)K-US

Solis Manual S5 (75-100)K US V2,3(20230623) tbl=13.r5 h=7868f947bd08

Data