A Particularly Pernicious Pressure Problem

[November]

I encountered a quirk with my pressure guage while tinkering the kegerator. I put a low pressure guage on the end of my 8 tap gas manifold. With the pressure on the low pressure regulator on the tank at 18 the guage on the manifold reads 6. All line lengths and diameters are fairly nominal. I use one of those fairly ubiquitous square bodied manifolds.

Does this amount of pressure drop seem reasonable?
When everyone talks about pressures in keg systems are they accounting for these kind of drops (assuming it isn't a guage discrepancy)?
I haven't ruled out that the one or both of the guages could be off too.

Typically, I would just leave the system as it is since I don't have any specific issues, but I was just curious about what's going on.

 

[day_trippr]

No, one shouldn't somehow lose anywhere near that much pressure. If there are spring-loaded check valves in the path those can drop pressure by .5-1 psi each (additive) but that should be it.

I would suspect the gauge. Find a way to test it...

Cheers!

 

[doug293cz]

The only time you get a pressure drop thru tubing, manifolds, etc. is when you have flow. The higher the flow, the greater the pressure drop. If everything is fully carbonated, and you are not actively pouring, the pressure at the end of the manifold should be the same as at the supply point (less any check valve drops as mentioned by @day_trippr .

Brew on

 

[November]

There is only one check valve between the two guages, system is not active and everything is fully carbed or otherwise isolated. I ordered a new low pressure guage. I suspect that one of them is funky.

New guage should be here tomorrow.

 

[November]

Yup, bad guage. It was off by more than double.

Thanks!

 

[Vale71]

Those dial type gauges are mostly junk. I've had quite expensive ones read off by 0.5 bar out of the box. The problem is that they're not mechanically stable. Assuming they are properly calibrated at the factory they get bumped so hard and so often on their way from China to the end user that any calibration performed at the factory was just a waste of time.