How to Test a Limit Circuit

Can't find all the limits in the safety circuit? Has the board failed? Use this strategy to quickly and easily identify if there is an open safety/limit or a potential faulty board on a furnace.

[@dw-ie2my]

You are the man. Great description, and will be super helpful for me to narrow things down.

[@jimoliver5758]

Enjoy your videos. Keep the good work up

[@HabeggerHelp]

Thank you sir!

[@dougrodger8208]

Thanks for doing these videos

[@user-lo2bb5hl8j]

Good stuff Shawn

[@arundelraghubir]

Great tip Sir... Thanks for sharing BRAVO!..

[@wkobayashim]

My Bryant 915SA48080S17 is heating up but throws a 33 after 3 minutes. The filter is brand new, and I even opened up the blower door, but the 33 is still popping. Any suggestions?

[@HabeggerHelp]

If it’s within 3 minutes and filter is clean, registers open and such…I would think dirty secondary HTX or gas pressure.
Many items affect limits, but tripping in 3 minutes eliminates a lot.
We have seen issues with insulation not allowing proper airflow around the limit…but it runs longer than 3 minutes.
Could be faulty limit but that’s rare. My guess would he dirty secondary or something blocking airflow.
Any checks beyond filters and registers should be performed by a trained professional.
I do a lot of DIY work myself, but replacing a trap on the sink won’t burn the house down as an example.
Not knowing your skill level, just making sure that’s clear.
Good luck.

[@mattvanatta387]

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