2 - zone grease heat system one works the other doesn't.? I heat my house using a 2 zone heat system. The upstairs...

I heat my house using a 2 zone heat system. The upstairs works really nice, but the downstairs zone does not turn on. I have set the programmable theromstat 20-30 degree higher than room temp. Still does not fry the 1st floor. What else can I check?
How do u fix a scrap disposal stuck...
Answers:    circulator, zone valve,circulator relay. All depends on your set up for how the zone are controlled. If that doesn't help consequently please give more details.