My house is heated via hot water. The water is circulated by a circulation pump. Within the house, there is a simple mercury thermometer switch for every zone. In the garage, there is the same mercury switch. The power feeding the mercury switches is 12VAC. Here is the issue. In there garage, there is a 220V blower. The blower is triggered via a 24VAC transformer. How do I attach the blower and circulation pump to the mercury switch? My plan was to purchase a 24V relay. The blower would go through the mercury switch and then T-off. One leg back to the blower and the other to the relay's coil. The coils return would have a diode in-line and then return to the blowers relay. The relay's switch side would complete the water pump circuit, replacing the mercury switch that would normally control the circulation pump. One issue I see is that the relay's coil is being powered by AC, not DC. Is that an issue? Here is a link to my idea. polacek.org/14678_garage.bmp Thank you for your time.
polacek.org/14678_garage.bmp I think I solved it. I will add a 5V line to the system. I have a four conductor from the the boiler room to the garage thermostat. Two will go to the 12V and I will use the other two for the 5V relay. Hope your site picks up more traffic.