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DKS
Damn Kidney Stones
Premium,ExMod 2002
join:2001-03-22
Owen Sound, ON
kudos:2
reply to Gemstone

Re: Honeywell Round Thermostat

said by Gemstone:

I have an old Honeywell round thermostat on the wall... It has only 2 wires going to it... Is this a low voltage or line (high) voltage thermostat?

I remember one of those with a little vial of mercury to help tip the spring over. Probably a toxic hazard, now.
--
Need-based health care not greed-based health care.


SparkChaser
Premium
join:2000-06-06
Downingtown, PA
kudos:3
Reviews:
·Verizon FiOS

said by DKS:

I remember one of those with a little vial of mercury to help tip the spring over. Probably a toxic hazard, now.

Yes, they did away with those a while back. I have the mercury switch out of one. I use it sometimes when I want to get a no bounce switch closure.

HarryH3
Premium
join:2005-02-21
kudos:3
Reviews:
·Suddenlink

1 recommendation

reply to DKS

said by DKS:

I remember one of those with a little vial of mercury to help tip the spring over. Probably a toxic hazard, now.

The little vial of mercury wasn't there to help tip anything over. Look closely at one and you'll see that there are also two wires inside the vial. The thermostat calls for HVAC "On" when the spring tilts the vial enough to move the mercury to the end of the vial where the two wires are located. Mercury is a metal and is conductive. The mercury completes the circuit by shorting the two wires to each other when it rolls to the "wired" end of the vial.