Rheem Touch-screen clicking noises
I wonder if anyone can educate me on these new generation thermostats.
I have a Rheem 400-series touchscreen stat that was installed with my RGFD Contour furnace. I've always noticed that when it cycles on or off there's a noticeable, though not annoying, "click". My first question -- is this because new stats no longer use the little mercury-filled bulb, like the 20 year old Honeywell round that was here with the old furnace?
And what replaced the mercury switch, a mechanical switch that makes the clicking sound?
Third question -- and the one that's really puzzling me during this cold snap -- why do I hear TWO rapid clicks each time it cycles on or off when the outside temps are below 20F or so? As far as I can tell, the burner and blower are operating at about the same level as when it's warmer outside, and I see the same uppercase "H" on the furnace display.
The manual doesn't explain any of this, so thanks in advance for your insights.
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Last edited by jpsmith1cm; 01-15-2012 at 09:50 PM.
Reason: No *
Relays replaced mercury bulbs so clicking is typical of about all digital stats except a few that use triacs.
Not sure why the modstat clicks twice. If you have the H appearing, that means the furnace is receiving the modulate signal so the firing rate should be varying. Since the inducer runs on high on all but the 40% rate, it may be a bit hard to tell what level it is firing it just by looking & listening. Airflow would vary, that may be the only way to tell.