I had to make a borderline call other day. We have a Community building that has an Early Childhood Education Center in it. The Heating/Cooling system is a hybrid system with a Hot Water Boiler, Cooling Tower, Heat Exchanger, and Water Source Heat Pumps in each room/ Pod. The Boiler was down. The problem on the Boiler was an electric solenoid valve that was bad. I didnt have a replaceable coil for it so I removed the plunger out of it and modified the remaining rubber diaphragm so it would feed the main gas valve with about 11inches WC of LP. My Dept General Manager said we had to get the system up so I decided to alter the valve. We ordered a new valve which is two days out. I tested the Hi Limit Control and that works properly. The system is on an Energy Management system so we can monitor it regularly from our office and we physically stop by and check it periodically while we are waiting for new valve. How often do other techs have to make borderline decisions regarding similar [safety} devices.