Sun Dec 29, 2019 2:13 am
That is an R-1 regulator, I believe. The label changed for the R-2, 3 adding the words "Double Diaphragm" above "2 Stage Regulator". They were not very good performers especially with the OEM 1" hoseloop. The tiny non-return valves are buried under a fold in the mouthpiece which restricted air flow badly. They aren't much better with larger mouthpieces like the USD sets.
They have a very simple second stage that was placed 45 degrees away from the intake air horn which simply filled the boxes with air which had to find its way into the air hose. The R-2 was the same, but they moved the orifice to be directly in front of the intake horn in the R-3s. That helped some.
Herman is correct: finding parts is difficult and they are old even if NOS. No one is making reproduction diaphragms, yet. It's doubtful anyone will. IF all else is good, and you have a good intake diaphragm, the second, exhaust diaphragm can be replaced with a reproduction duckbill. This actually improves the exhalation effort.
The Dacor line of DH regulators is generally not very popular, and these R-1,2,3 series regs are at the bottom of the heap. You won't sell it for much on eBay if that's the plan.