How To Test If You Have A Bad Home Thermostat

How to properly diagnose home thermostats with a multimeter and/or jumpers.
• How to Bypass/Jump a H...
00:00 Tool use and T-Stat Switching
01:37 Transformers and Two R Terminals
03:30 How Switching Works w/Continuity
05:35 Power To R Terminal & Mistakes
08:18 Voltage On Open/Closed Switches
10:27 Testing With Jumpers

[@elgkas9928]

For a beginner like myself, another great video that makes things so simple to understand.. Keep the videos coming professor!

[@meangreen2792]

🔥💯 OUTSTANDING video and demonstration 💯🔥 Thanks for showing the step by step of this. 🔥 Keep these videos coming. 💯

Another great video, Sir. I now am sure that, I am able to trouble shoot the low voLtage circuit, because of you. i actually was able to understand you fully, because of the thoroughness you provided. I doubt it very much, that any one else out there could have explained this with such clarity. Thanks a million. I am in retirement, and I am now positive that I will be able to make some extra income, because of you. Been on a fix income, and barely making ends meet, I now will be able to service heat pumps for friends and relatives, and make some extra money. I thank you from the bottom of my heart SIR. God bless you.

[@JerseyMikeHVAC]

God bless!

[@globecomputers1]

Awesome video very thorough and detailed. Thank you.

[@JerseyMikeHVAC]

You're welcome.

[@stevencossaboon3237]

Great video Mike. Thank you for the knowledge.

[@JerseyMikeHVAC]

You're welcome

[@jeremyjedynak]

It would be great to see a video on how to check how accurate the thermostat reading on the display is, and whether the built-in offset adjustment needs to be configured.

[@brianmcdermott1718]

Great info. Thanks Mike.

[@sermore77]

Great teaching on thermostat👍🏼😎

[@PosterityOf1776]

My in-laws a/c system went down. I discovered that the BACKPLATE for the nest shorted out. this caused the contactor coil to burn out , the fan to stay on and the 3-amp fuse to blow. I removed all the wires from the backplate and everything was fine. New backplate.

[@JerseyMikeHVAC]

Good job

[@karellfernandez73]

Excelente video. Thank you.

[@marvinmachado-du3bv]

Great Video 👍

[@lovemorejenami2196]

That's fantastic

[@joesnider3727]

Thank you! Greatly appreciated. I have the same honeywell tstat and the fan comes on in heating and cooling modes. But when trying to turn on in just fan only on or circulation modes, the fan does not come on. How do I test to see if that is a tstat issue? Thank you!

[@JerseyMikeHVAC]

Jumper R to G. If the fan comes on that way but not in the ON position without the jumper, it's the thermostat.

[@korruptsociety421]

Hey again. I wish there was a way to directly message you. I'm still having some issues with my heat, and I need to try to replace the thermostat, or just return it could you please help me figure out how to connect this thermostat from the old mercury one? And potentially do some basic trouble shooting? I'd greatly appreciate it, thanks

[@lisamulcaster1522]

Is there a video for install nest when there are 2 wires in R spot & then a jumper wire from R to Rc?

[@JerseyMikeHVAC]

If there is a jumper from R to Rc then both R terminals are treated like a single R terminal.

[@lisamulcaster1522]

That would work if there was 1 wire in the R terminal but here was not. There was 2 wires in 1 terminal then a jumper on top of that from R to Rh. It had no power to ac with only 1 wire in R.

[@realSamAndrew]

For the style that completely pulls off the wall and runs on batteries, can't you test the thermostat itself directly by calling for heat or cool and probing the contacts for continuity? Instead of jumpering the wires in the wall.

[@JerseyMikeHVAC]

Yes, you can do that too, but that requires shutting the power off.

[@realSamAndrew]

@JerseyMikeHVAC wouldn't you still have to shut off power if you pull the front piece off to get to the wires behind the wall? After the thermostat is disconnected, it can be tested independently, as long as it is battery powered.

[@JerseyMikeHVAC]

@@realSamAndrew No, you still have power on the wires and terminals. Battery just operates the switching.

[@realSamAndrew]

@JerseyMikeHVAC I think you misunderstood. The thermostat needs to be pulled off the wall to access the thermostat wires going to the air handler so you can jump them if that is the plan. Correct? Now once the thermostat main unit is in your hand, you can test it on a table with no regard to a system or line voltage *if it runs on battery power* .Correct? It's just a fancy switch that you can test like any other switch.

[@JerseyMikeHVAC]

@@realSamAndrew If the thermostat is designed for that then sure. I just assume in practicality the thermostat is being tested because something isn't working. Jumpering will tell you right away if it's a system problem or a likely stat problem. But there's no rule it has to be done a certain way. If you want to test the stat on the table then that's fine.