Limit switch control method for a two-stage furnace
CA 1312128 C · Owner: Ballard, Gary W. · Inventors: Ballard, Gary W.; Thompson, Kevin D.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A two-stage gas furnace control system automatically shifts into a high fire only mode if, in two consecutive low fire heating cycles a limit switch is tripped to indicate that a gas valve is stuck in a high fire condition. In this way continued operation, is allowed to proceed in a safe manner. Provision is also made to lock out the system from further operation if while in the, high fire only mode, the limit switch is tripped in a predetermined consecutive number of cycles or if while in a, preemptive low fire only mode the limit switch is tripped.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted December 29, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 29, 2009.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.