Solis RelayChk-FAIL (Alarm 1035) — Grid Relay Self-Check Failed
What it means: Every time a Solis inverter prepares to connect to the grid it tests its own internal grid relays — the physical contacts that join your system to the supply and, more importantly, that pull it apart when the grid goes away. That self-check failed, so the inverter refused to connect. Solis logs it as alarm 1035 and describes it as a relay self-check protection failure; their service centre attributes the common case to a relay that has stuck after continuous operation. The inverter not generating is the safe outcome here, and it is deliberate.
Why does Solis show RelayChk-FAIL?
- Relay contacts welded or stuck after a very large number of connect/disconnect cycles — Solis's stated common cause
- A grid-side wiring fault that the self-check reads as a stuck relay
- Incorrect AC polarity or wire sequence at the AC connector
- Abnormal neutral-to-earth voltage at the inverter's AC terminals
- A genuinely failed relay or driver circuit on the inverter's AC board
The Pakistan factor
Pakistan gives these relays the hardest duty cycle they will see anywhere. Every load-shedding slot, every feeder trip and every voltage excursion that pushes the inverter past its grid limits ends in a full disconnect, and every restoration ends in a full reconnect. A unit on a heavily shed feeder therefore accumulates far more relay operations per year than the same unit would on a stable supply, and relay contacts are a wear item with a finite number of operations in them. That does not make RelayChk-FAIL normal, but it does mean that a Solis showing it after a few years on a badly shed feeder is most likely worn rather than defective — worth saying clearly, because it is a repair with a known cause rather than a mystery. The other local contributor is neutral quality: an unstable or floating neutral upsets the neutral-to-earth voltage the self-check depends on, which is why Solis's checklist measures it, and why an installer should look there before anyone condemns the board.
How to fix it
- Do the manufacturer's own first-line step once. The manual's instruction for any Table 8.1 alarm is to shut the inverter down following the stop procedure in section 5.2, wait five minutes, and restart it using the start-up procedure. Solis service adds that letting the inverter sit discharged for around 30 minutes sometimes clears it, and that if it then runs normally you can leave it be.
- Do this at most once or twice. If the alarm comes back, stop restarting it. Every restart is another operation of a relay that has just failed its own test, and repeated cycling makes a sticking contact worse rather than better.
- Write down the model, serial number, firmware version, grid standard, installation date, and how often the alarm appears per day. Solis asks for exactly that set before they will diagnose it, and having it ready saves a wasted service visit.
- Do not open the inverter, and do not let anyone talk you into "freeing" or bridging the relay. The relay is on an internal board behind capacitors that stay charged after the unit is shut down, and it is the component that disconnects your system from the grid when the supply fails. Bypassing it would leave your array energising a dead feeder that a lineman may be working on.
- Have your installer check the outside of the problem first, since it is cheap. Solis's checklist for them is to verify AC connector polarity and every connection from the AC connector through the distribution box to the grid source, and to measure line-to-neutral, line-to-earth and neutral-to-earth voltages at the inverter's AC gland.
- If the wiring checks out, this is a manufacturer service-centre job, not an installer job. Relay or AC-board replacement happens at Solis service. Raise it as a warranty claim before agreeing to pay for a board — a relay that has worn out in normal service is exactly the kind of failure a warranty is for.