Boiler was turned down to 50 degrees when I got to the house. Boiler did not operate when tested (Short cycling). I had 155 degrees at the faucets. No water heater was found, but noted a 1/2 inch copper water line on front of boiler appeared to be supplying hot water water. (Gray box on front). Is this possible without boiler working?
Yes it is possible. If you meant thermostat was set at 50 the boiler circulating pump was not calling for heat. However the boiler internal water temp can be somewhere from 160 to 180 f just on hold waiting for thermostat to call for heat circulation. Hot water is provided by a tank less coil, that water can be scalding,that is why a tempering valve is used to drop domestic hot water to a safe temp of 120f. Your system has no visible tempering valve, resulting in scalding water. By short cycling if you meant the oil burner turns off an on quckly…every few seconds…then there is a problem that needs service.