Re: Heater thermostat.

Posted by JWL On 2014/7/5 21:43:40

Howard, might they have been the higher temperature thermostats to take advantage of the then new permanent type anti-freeze and pressurized systems? Prior to the permanent type, an alcohol type anti-freeze solution was used. Its boiling point was relatively low and thermostats in the 140F range were commonly used. Also, non-pressurized systems were common until the late 1930s.

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