Raytherm Boiler Age

The model # is 100WT, S/N is 01856534. I had heard that the first 2 digits are the year, therefore 2001? Any help would be much appreciated.

I believe that one is January 1985.

Thanks Russel, that makes more sense.

The first 4 digits can be either month/year or year/month. You can use your discretion depending on the condition of the boiler. These boilers are also know for cracks in the refractory material on the sides of the heat exchanger, so watch for this. This is a priority repair as they prevent combustion products from entering the home and prevent overheating of the cabinet.