i hate to say it but i am stumped on this boiler. i have never worked on one before this, and i can only work on it about 20 minuts at a time. first i found the transformer was bad, changed it out. now the sentry 2100 controller is not modulating the fan, changed it out.now it has an air switch code, found it would not close. changed it out with the upgrade kit. still the same code, found loose connection at controller. fix connection, turn power on and the controller smokes. checked all wires, good. changed yet another controller and this time everything is fine for about 2 minuts and then the controller goes blank but the burner lit and ran great. so i change it one more time and now i get a water temp code. tech support is not much help because they are reading the same book i am. i dont know what else to do. any idea's?