I am replacing my old ITT T80BV100J (for use with millivolt, 24 VDC @ 0.60 amp) controlling my existing gas fired gravity floor furnace with a new Honeywell CT50K standard t-stat. Connecting to the new Honeywell seems straightforward with terminals R for power and W for heating. The old ITT t-stat though has no markings on the connectors one on left and the other on the right. Can anyone help me with which one is which on the old t-stat?