Which pressure gauge to trust? Built-in vs external pressure gauge

#1: Post by **samuellaw178** » March 2nd, 2012, 8:44 pm

Just wondering, if your reading on built in pressure and external pressure gauge differs, which one are you likely to trust? Both rest at 0 without pressure for reference.

1.0 bar on the built-in, 1.2 bar on the steam wand pressure gauge

#2: Post by **allon** » March 2nd, 2012, 9:26 pm

The cheap Omega's have an accuracy of 3% over the first and last 10% of their range, and 2% over the rest....

http://www.omega.com/Pressure/pdf/PGC.pdf

so you're probably within 2%....

What model Omega is that?

Lord only knows the accuracy of the internal gauge.

If you can get a boiler temperature, you can figure it out yourself.....depending on the accuracy of the thermometer

#3: Post by **Randy G.** » March 2nd, 2012, 10:03 pm

If you assume each gauge has an error of +/- 1%, they could both be within specs.

#4: Post by **duke-one** » March 2nd, 2012, 11:33 pm

I bought one of these, about $100, reliable, cool looking available in any pressure range and can switch engineering units any time.
http://www.dwyer-direct.com/shop/itemDe ... em=DPGW-08

#5: Post by **boar_d_laze** » March 3rd, 2012, 1:34 am

Randy G. wrote:If you assume each gauge has an error of +/- 1%, they could both be within specs.

Hey, what's an order of magnitude between friends?

BDL

March 3rd, 2012, 7:33 am

Thanks for the replies!

Allon,
I have no idea what model was the Omega gauge. It was the steamwand pressure gauge from OE with the rubber tube. I guess you're right. I am not sure how old is the gauge in the machine. The last owners said it was just replaced recently, which could be years.

Duke, I wish I could, but probably not now because of the price.

Randy, that could be a possibility too. Thanks for your weighing in.

This goes to show not to rely too much on the number. Adjust base on taste. Gotta to improve my cooling flush more.

#7: Post by **allon** » March 3rd, 2012, 7:50 am

samuellaw178 wrote:I am not sure how old is the gauge in the machine. The last owners said it was just replaced recently, which could be years.

Just because it may be old doesn't mean it's inaccurate.
My point is that you can't tell without measuring the accuracy; the Omega ones come from the factory certified to a certain accuracy, but even that is no guarantee for a gauge of unknown provenance.

Also note that a gauge's accuracy may vary across its range.