110v cheater as diagnostic tool?

[SBKold]

Went to use my trusty cheater cord at outdoor unit and no go for my shop vac.

Huh. Oh look no ground conductor.

Guess the indoor coil wasn't a good ground either

I checked and handler was ok.

[craig1]

With plastic drain pans the coil is insulated from the air handler. Once I saw a compressor that went to ground on an ungrounded condenser. The current flowed back to the furnace through the lineset and metal panned coil and melted the flex gas line. Luckily they were out of LP

[Greend88]

What'd they do run only two conductors too the unit?

[mark beiser]

The first 3 or 5 times I got zapped using a cheater cord didn't convince me, but almost killing a helper did.
I was using one outside to run my recovery machine while my helper started on tearing out the indoor unit. He started with disconnecting the wiring from the air handler, and got hit hard as soon as he pulled the ground wire loose from the air handler.
The outdoor unit turned out to have no ground, so the current was traveling through the refrigerant lines and air handler cabinet to its ground.
When he pulled the ground wire loose, he became part of the circuit through his body.
It screwed up his heart rhythm, so he had to be defibrillated in the ER, and spent a night in the hospital under observation.

I haven't used a cheater cord since that day, I'm not sure if I even own one anymore.

There is a reason they are commonly referred to as "widow makers"...

With plastic drain pans the coil is insulated from the air handler. Once I saw a compressor that went to ground on an ungrounded condenser. The current flowed back to the furnace through the lineset and metal panned coil and melted the flex gas line. Luckily they were out of LP

I've had a situation kind of like that with the insulation on a wire in the outdoor unit that got rubbed through, but the evap had a PVC drain pan, and rubber grommets for the refrigerant line connections.
The system was running when I was standing in front of the furnace grabbed the liquid line to see how hot it was. My elbow touched the vent pipe at the same time, so I found out the LL was the wrong kind of "hot".

When I jerked my hand off the LL, it slapped against the side of the coil. The arc blew a hole in the LL.
While dealing with that, we also found that the flex gas line to the stove arced to the back of the stove and blew a hole in the gas flex.
It was jetting fire against the wall. It had a fireproof covering on it, but it set the 40+ year old cellos insulation in the wall to smouldering....

It was later revealed that the outdoor unit was using the EMT conduit as the ground, but it had come loose from a fitting at a junction box in a utility closet. The only "ground" the furnace had was the gas line.

[SBKold]

Yep. But the disconnect was grounded.

[Hindermanhvac]

Might be a stupid question, but what is a "cheater cord"?

[Redwood650]

Might be a stupid question, but what is a "cheater cord"?

Its basically a stepdown from 240v to 120v by using 2 alligator clips, one to line voltage on the disconnect, the other to ground. the end of the 2 clips have a standard 120v outlet to allow you to run any 120 appliance.

[GATS]

I carry one that works opposite. Male plug with clips for the female end. For running 110v motors and equipment uninstallled.