On the display
The panel shows SYS X HPCO FAULT. In the fault table the line is printed as SYS X YYYYYYYY HPCO FAULT: X is the system number, and YYYYYYYY is the field that reads FAULT or LOCKOUT, so the message appears in one of these two forms depending on how the trip is being handled.
What it means
This message means the mechanical (hardware) high pressure cutout — the HPCO — protecting that system from dangerously high discharge pressure has tripped: its contacts have opened. The HPCO is wired in series with the VSD Run Signal and is only checked when the system is running, so the trip can only be detected during operation. Unlike most system faults, it occurs immediately and does not wait the 3 seconds the manuals give as the typical delay. The system faults and shuts down immediately.
Why it appears
- The mechanical high pressure cutout contacts open, protecting the system from dangerously high discharge pressure. The cutout opens at 23.2 barg ± 0.55 barg (337 psig ± 8 psig) and closes again at 17.4 barg ± 0.69 barg (252 psig ± 10 psig). This is the only cause the manuals give for this message.
Setpoints and thresholds
- Trip point (cutout opens): 23.2 barg ± 0.55 barg (337 psig ± 8 psig).
- Reset point (cutout closes): 17.4 barg ± 0.69 barg (252 psig ± 10 psig).
- Detection delay: none — the fault occurs immediately and does not wait the 3 seconds typical of most system faults.
- Auto-restart: when the 120 second anti-recycle timer times out.
- Lockout: on the 3rd fault within 90 minutes.
Reset and restart
The shutdown is immediate. If the display shows FAULT, the system restarts by itself when the 120 second anti-recycle timer times out. If the display shows LOCKOUT — which the manuals tie to the 3rd fault within 90 minutes — the system will not restart until the operator clears the fault using the keypad. The clearing step printed for this lockout is to cycle the respective system switch OFF and ON to clear
.
Questions engineers ask
What does SYS X HPCO FAULT mean on a YORK YVAA?
It means the mechanical (hardware) high pressure cutout protecting that system has tripped on dangerously high discharge pressure. X is the system number, and the system faults and shuts down immediately.
At what pressure does the YVAA HPCO trip?
The cutout opens at 23.2 barg ± 0.55 barg (337 psig ± 8 psig) and closes again at 17.4 barg ± 0.69 barg (252 psig ± 10 psig). It is only checked while the system is running.
Why did my YVAA shut down at once with HPCO FAULT?
The HPCO is wired in series with the VSD Run Signal, and unlike most system faults this one is acted on immediately — it does not wait the 3 seconds typical of other system faults — so the system shuts down at once.
How do I clear an HPCO LOCKOUT on a YORK YVAA?
A plain FAULT clears itself when the 120 second anti-recycle timer times out. A LOCKOUT, given on the 3rd fault within 90 minutes, must be cleared by the operator using the keypad; the manuals' printed clearing step is to cycle the respective system switch OFF and ON.
Messages next to this one
The same message on other models
Source
Written from the manufacturer's manuals for the YORK YVAA; every number and designation on this page is checked against them before publication. The row of the manual this message comes from:
All YORK YVAA messages: fault codes · YORK YVAA documentation · YORK manuals