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Old 12-01-2017, 12:43 PM   #7
Badcaps Veteran
Join Date: Dec 2010
City & State: Alberta
My Country: Canada
Posts: 1,483
Default Re: Looked at new thermostats, nah I'll DIY this

Where did you put the temperature sensor?

I found the heat made by a thermostat messes up operation.

Honeywell mercury-switch tube, the skinny flex wires heat up, up to 10 degrees at 0.2A. Took me long time to figure out why the temperature was never consistent. see pic

The Pi and relays can make heat too.

Another house I owned, the wall had drafts and cold air blowing through the junction box. That made the temperature move around too.

edit: added pic
Attached Images
File Type: jpg Honeywell bimetallic mercury thermo.jpg (71.8 KB, 18 views)
File Type: jpg Honeywell thermostat pic.jpg (194.6 KB, 19 views)

Last edited by redwire; 12-01-2017 at 01:09 PM..
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