In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
I must be suffering from cerebral flatulence:
WM hot water boiler CG-6-PIDN 175mbh NG> found the Tricator gauge reading about 45 psi static cold but the PRV is not discharging (rated 30psi). Hose thread pressure gauge at boiler drain reads 16 psi. Two story house. Steel expansion tank drained and re-tested-same.
Since it was an old relief valve, I changed it along with a brand new tricator gauge. Re-installed and still reading twice as much at tricator as at drain cock.