I have an oil boiler and it's steam. The previous owners converted downstairs into an in law suite. In addition they also installed another thermostat in this new section which I am currently renting to tenant. My dilemma is that because this is one system with duel thermostats the tenant can call for heat at anytime. I want to know if there is any way around this. I have already installed a lockbox but I think the tenant still has access. Help...