Question about Heating & Cooling
The Blue knob is for cooling the red for heating. I would reccomend replacing it due to the fact the age and it probably has yrs of dust built up on the mercury bulbs which can throw the tempurature off. Dust on these old mecury style thermostats is its worst enemy. The bulb is very sensitve and enough dust can throw the bulb of several degrees.
Posted on Dec 21, 2008
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Posted on Jan 02, 2017
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