Q?? for Doc

[hungry]

Doc
Furnace is Ruud silhouette II plus 2 two stage 80%

recommended thermostat is 2 stage. What's on it now is a regular mercury bulb t-stat and furnace does 3 cycles an hour. on for 5 minutes and off for 12 min. temp swing about 2deg.
changed it to regular digital and furnace did 6 cycles an hour, on for 5 min. and off for 5 min. maintains constant temp. HO did not like it(said runs too much) so changed it back to mercury bulb.
Q? How does a 2 stage t-stat work? and how many cycles will it do an hour? AND how benificial is it to HO?
Need third party opinion please.

Thank you

[Jultzya]

A 2 stage furnace deserves a 2 stage stat.

The 2 stage stat will allow for longer run times as the unit will never see the 2nd stage of heat unless the temp of the space continues to lower. Then at that point the high stage is energized to recover, then goes back to the first stage when it falls close to the set temp.

Longer run times offers the client the maximum efficiency they can receive from said equipment.