The amount of oil in your gages is not measurable enough to make difference. It would be like 1 drop of water(or less) in 40 gallons of gasoline. Just my opinion.
Originally posted by ruud-man
All I know is the 410A system uses POE and the R22 uses mineral oil. R22 is not compatible with POE and 410A is not compatible with mineral oil. For the cost of a set of gauges I don't know if it is worth the possible problems.
So, no, I don't see the practicality of trying to use the same gauges.
Buy a second set...http://hvac-talk.com/vbb/images/icons/icon12.gif