If it's on the outside, won't PNG take care of it?
If it were on their side they wouldn't use a customer supplied regulatorDon't know the details but PNG is who told him it was leaking. I'm guessing he would have had them replace it if that was an option unless the cost was thought to be too high.
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PNG will repair is for a fee. They dont much for free anymore.
That is a Maxitrol 325-3 if it has 1/2" threads. If its 3/4 threads its a 325-5. Any HVAC or plumbing supply will have them. Amazon also has them.