bypassing a thermo stat

Hi I was performing an inspection few days ago, the HVAC system won’t be able to operate. The digital thermal stat has no display at all whatsoever. The buyer’s agent said the last home inspector he used know how to turn on the HVAC by bypassing the thermo stat. I was just wondering if this is the standard of practice of an HI, any help?

Max if it doesn’t operate at the normal controls I report it as in need of repair… I wouldn’t pay a lot of attention to what agents say their normal guy does…

No its not standard practice, I know how to jumper it but I don’t unless the stat is missing on a repo. If there is no digital display the battery’s in the stat are prolly dead I do carry extra battery’s and I do replace them in order to test the unit

Define normal pleez never met one:p

and You’re not likely to find one around here Charley…just sayin…

By passing not a good idea . Some have an anticipator in them and you can burn them out .

Charley is talking about bypassing at the HVAC not the control Roy. All this does is allow you to see the flame pattern and operations at the unit. This is above what a normal Home Inspector should do.
3.4. Heating

I. The inspector shall inspect:

the heating system, using normal operating controls.
II. The inspector shall describe:

the location of the thermostat for the heating system;
the energy source; and
the heating method.

From International Standards of Practice for Performing a General Home Inspection - InterNACHI

Not so if the stat is missing as I stated

Ya did not read what I posted try again;-)

I did Charley. Sorry I assumed you did what I do when the therm is not in question and we were posting at the same time, so I did not see your last post. LOL


What are the chances of “shorting out” the mother board of the FAU by crossing the wrong wires?

The only thing you can do wrong is if you jump the common wire (if there is one) with an energized wire.

If the 24 V control circuit is not protected by an in-line fuse (and most are not), you will burn up the transformer.

If anyone out there doesn’t know how to determine the common conductor, best leave it alone.

As Dave stated not all stats have a common some do some don’t most stat are a switch not a load so no common wire to the stat base.

My son just cut his stat wire to the outside unit with a weed eater and that wire has both common and a hot side he was messing with it trying to get it back on and shorted the two wires together it blew a inline 3 amp fuse in the FAU control panel old Dad had to repair, the fuse saved the transformer

just some more superfluous information…

The high-voltage side of the transformer primary windings are what gets cooked. The wire is about the size of the hair on your head (if you have any)! Doesn’t take much, or long to go “pop”!

Does it go pop or is there smoke:twisted:


is that some kind of bald guy crack ?

Are you saying u head looks like a cue ball or is it just shaved close:p just saying

How did this conversation get from bypassing a stat to a bald head:shock:???