I purchased a home with a hydrokinetic heat storage system and have not been able to find any technicians who know aynthing about the unit. The unit is at least 20 yrs old. It has functioned efficiently for the last 7 years. I noticed the unit thermostat reading 100f today. It's usually at 140 especially on cold days like today. I normally keep my house at 65 and found it was only registering 63 degrees. I ran it manually for a short period and it seemed to function properly but temp did not increase. I added some water. The sight guage in the expansion tank is black and useless so I am unable to tell how much water is in there. At one time I was advised to tap the tank with the back of a screwdriver but I can't determine if that's accurate. Any advice or referral to a tecnician in the Central NY area (between Binghamton and Oneonta) would be greatly appreciated.