Vacuum gauge testing

[magicno1]

Just want to clear this up.
Just finished my oftec training at Grant. One thing they wouldn't really cover was how to test the oil supply for blockages/ leaks using a vacuum gauge. Very annoying as I like to learn as much as. I also done the burner course, vortex and Combi courses in Jan and it wasn't covered then either.
So.... Can anybody explain ow to do it and what to look for as in gauge readings etc etc or is it worth doing at all as most of the guys seem to think nobody uses their vacuum gauge!
cheers

 

[TFGplumbing]

vacuum gauge is handy for finding blockages or restrictions ie a crimped pipe. If for example an isolator was turned off on the line and you had your vaccum guage connected you'd see very quickly.

You are really going to be looking for a reading of 0 from the vacuum guage test port during operation, dont put it on the pressure test port

although I was told a reading of around -0.3 is okay.

 

[magicno1]

vacuum gauge is handy for finding blockages or restrictions ie a crimped pipe. If for example an isolator was turned off on the line and you had your vaccum guage connected you'd see very quickly.

You are really going to be looking for a reading of 0 from the vacuum guage test port during operation, dont put it on the pressure test port

although I was told a reading of around -0.3 is okay.

What reading give or take would you expect on a blockage?

 

[TFGplumbing]

anything over -0.3 is what I was told, most ones I have tested have been 0 vaccum so I would be suspicious even if it was a bit.

if it proper blocked the vaccum will just rise and it will lock out

Handy guage in the right circumstances

 

[John Flower]

Also used to ensure that the pipe work has been sized correctly and doesn't not exceed the pumps suction head!!

 

[Rickster123]

Also used to ensure that the pipe work has been sized correctly and doesn't not exceed the pumps suction head!!

Welcome back to the forum john! Are you by any chance the john flower from eagaheat??

 

[Kevin D]

Most of the time when the vac gauge is connected to the vac port a steady increase in vacuum will indicate a total blockage. Ideally the reading will never drop below zero. Any reading below zero will cause vapours to boil off in the oil these vapours if caught in the pump gears will cause excessive wear and shorten pump life considerably.

 

[John Flower]

Oops yes i am the John Flower from Eagaheat !

 

[Rickster123]

Oops yes i am the John Flower from Eagaheat !

You wouldn't remember me, I was in the southern area, not on your patch. I still miss those good old days.

didnt you and mike Jackson have matching leather jackets??

 

[Kevin D]

Sounds like the Grant brothers

 

[Bunker]

Wont the opposite be true aswell, a negative reading shows an air leak?

Most of the time when the vac gauge is connected to the vac port a steady increase in vacuum will indicate a total blockage. Ideally the reading will never drop below zero. Any reading below zero will cause vapours to boil off in the oil these vapours if caught in the pump gears will cause excessive wear and shorten pump life considerably.

 

[Kevin D]

Not necessarily bud. An air leak will relieve any vacuum forming, maybe up to the point that it won't show at all. It will show as a fluctuating needle on your pressure gauge.