Yong Heng gauge went BOOM!

Hmmm. Why would it trip the circuit breaker?

Reason # one million and one why you should always wear eye protection when doing anything even remotely near high pressure. Glad you're ok man

Hmmmm, should the gauge bezel even be holding pressure at all? The bourdon tube should be holding the pressure, not the gauge.

Hmmmm, should the gauge bezel even be holding pressure at all? The bourdon tube should be holding the pressure, not the gauge.

Click to expand...

Seems reasonable to me. 

If a wire from the auto shutoff switch grounded out to the bourdon tube mechanism and arced a hole into it, it would explain the tripped circuit breaker, the burn marks, and the blowout of the gauge lens.

James

Those gauges are junk for sure I have replaced two of them in both of my units. Need a new one every year or a bit less. 

They went pop but didn't blow a breaker or blow the gauge apart like yours.

That probably woke up people.

BUT ! try the same on a car sized AUX engine in a ship and with the fuel pressure gauge, and the damn thing burning MDO and not sweet pure diesel,,,,, and you are in for a cleanup.

And then do that almost every month and if you are the one that have to put on a new gauge,,,,, and clean the immediate surroundings,,,,,, no fun at all, and you start to curse engineers and gauge makers.

And you start to second guess yourself as it was after all you that put on that gauge, even if there are not really any way to put on that gauge wrong.

The set pressure setup is a weak design. Mine lasted about 6 months, and the gauge became unusable. In the name of cost savings they use line voltage on the pressure switch, a very bad idea in my opinion. Not many cheap gauges can withstand the insane vibration they are subjected to. 

Line voltage? I wonder if that could contribute to the failures.

I believe TheIceman above is probably correct. The gauge probably was shaken to failure, shorted to pressure tube and burned a hole in it. There is of course a cheap relay inside that is also beaten to death as well. If I need my YH again, I’ll change the wiring and eliminate that part. It’s not worth the risk imho, pretty much destined for failure. 

Seems you should be able to find or make a 5 volts DC circuit and let the gauge trip a relay to open once the hands connect (a normally closed relay connection). Might need to go up to 12 volts, not sure if you'll find a high current relay that operates without a decent size coil to throw it. An SSR and flyback diode might be the thing to use.

Scary thinking a gauge similar to that is pressed against my right cheek on the regular.