Well, the job is done and it cost me $1.50 for a T15 Torx Tamper Proof Bit to remove the two screws holding the platic cowling on. After we got the housing off, under illuminated magnifcation on the work bench I found a burned and fractured joint on the PCB where the relay coil gets power. I cleaned the joint with alcohol and then reflowed the solder...checked for any other bad joints..found none. Carefully reassembled the PCB to the housing and back onto the valve using the T15 Torx bit....restored power, turned up the thermostat and we were back in business. Wish I done this years ago...would have saved a lot of anxiety and cold nights as well.