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Repairing Instrumentation
Questions about what parts could be repaired in transmitters and control valves

Hello everyone,

I'm Ahmed, Instrument and control engineer in UAE. I would like to know what parts in transmitters or control valves could be repaired and how to repair them.

For example, the smart positioner could be faulty, and this is due to relay damage. So instead of replacing the whole positioners, we could replace the relay and the problem will be solved with less money.

to sum up ..

1- if the positioner is faulty, what could be the problem?
2- Is the transmitter repairable? or I have to buy a new one?
3- is GAUGE repairable? ex: pressure gauge
4- is the regulator repairable?
5- is the booster repairable?

>1- if the positioner is faulty, what could be the problem?

Get the manual for it and find the troubleshooting section in the back part of the manual and read it. Most failures are probably due to dirty and/or wet supply air that gums up the internals. There can be electronic failures, too.

The options parts, like a re-transmit output, is usually a separate card or module that can be replaced, as needed.

>2- Is the transmitter repairable? or I have to buy a new one?

Again, check the back of the user manual for a list of components to see what is available for that model. Most industrial transmitters offer parts, but things like pressure sensing element is sold as an entire unit because there is little a repair shop can do to fix the sensing assembly.

>3- is GAUGE repairable? ex: pressure gauge

A very high end pressure gauge might be repairable, maybe, where internal parts available, maybe. Mid and Low end gauges are throw-aways.

>4- is the regulator repairable?

The diaphragm is probably replaceable.

You can always collect bad units and cannibalize parts from them units to see if you can fix a like model.