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When to upgrade an obsolete compressor control panel
Control panels outlive their spare parts. Here is how to tell when an FW Murphy panel has reached that point, and what a replacement actually involves.
The signals that a panel has reached the end
A compressor control panel rarely fails outright. It becomes unsupportable, which is a slower and more expensive problem.
- Spares for the panel are no longer available from the OEM, or arrive only as used units
- Nobody at site has the software or the setpoint records to change the configuration
- The shutdown logic has been modified over the years without documentation
- Displays or annunciator points have failed and been bypassed rather than repaired
- The engine or compressor has been modified but the protection limits have not
The last two matter most. A bypassed shutdown is not a nuisance, it is a protection function that is no longer protecting anything.
What a panel replacement actually involves
Replacing a panel is not a like for like swap of a box. The work is mostly in agreeing what the panel should do before anyone builds it.
On a recent upgrade for Pakistan Oilfields Limited at Khaur, the obsolete panel on the T Unit gas compressor was replaced with a programmed FW Murphy Centurion C5 panel. The sequence was: agree the control philosophy, confirm the protection points against the engine and compressor limits, build and program the panel, then supply it with its documentation.
A replacement typically covers:
- The control philosophy, written and agreed before the build
- The programmed panel itself, supplied by the OEM
- Field devices where the existing ones are unsuitable or unsupported
- Installation and commissioning supervision at site
Insist on the cause and effect chart
The most valuable document in a panel upgrade is the one that is easiest to skip: the cause and effect chart. It states, on paper, which input causes which alarm and which shutdown.
Without it, the protection logic lives only inside the controller, and the next engineer to touch the machine has to reverse engineer it. With it, setpoints can be reviewed, audited and handed over. Every panel GenCom supplies is delivered with its cause and effect chart for that reason.
If you are specifying a panel upgrade, put the control philosophy and the cause and effect chart in the scope of supply. It costs nothing at order stage and is very expensive to reconstruct afterwards.
Panel no longer supported?
Send us the panel model and the engine or compressor it protects. We will tell you the upgrade path.
Karachi, Pakistan · info@gencompression.com