Help me.

[Trydan]

Hi.
My name is Blair.
I'm an electrician from NewZealand, ive recently wired a new carwash with 3x ginsan self-service bays.
Now i have a issue, 6mths later.
24v Coils burning out on high pressure pump motor contactor.
The power supply is good. 27v.
But the coil hums and burns out. I replaced the original one, thinking it was faulty but it's happened again.
Problem is there are no drawings, and no details on what this gs-27 is or does.

Also the neutral/ black / a2 is switched somewhere? In nz we only switch the phase.

Any help would be appreciated

 

[Trydan]

More onfo.
Yes I wired it. I had the job of running all the wires, mains, power to site, main switchboard, lighting, tray etc.
But a tech from Australia came and hooked it all up and commissioned it.
The drawings don't match the install. They are basic drawings of the ginsan - no feild wiring to paystation or product selection. The drawing just shows the contactor being pulled in by an on/off switch on the ginsan cover - not correct.
Im guessing this gs-27 plays a role but I have no idea what.