Hey /diy/, On a heat pump system, I have 16V AC sitting at both

>>1097119
Last try for help

>>1097119
>Also, this is 16v to ground, not across.
theres something up with the ground

>>1097119
not a big AC guy but where is the power coming from if the disconnect is off? have you shut the power off at the breaker?

>>1097119
I'm not familiar with this layout. My system uses separate heat (gas) and AC. Bit easier to read.

Got a volt/Ohm meter? I'd start at the transformer and work back.

Your drawing has all the "options" so it's impossible for me to know what you have or don't have. Might want to remove those lines that your system doesn't have.

208/240 vs 18/24 could be the way it was wired. Make sure the connection matches your house voltage.

At any rate, 18 to Gnd is possible if that Red wire on 4 has broken. It would feed back from 5 Brown through that transformer coil on the right.

About all I can come up with using just your description and the schematic.

>>1097245
Yes, I verified that there is absolutely no power coming in except for from the yellow wire coming from the condenser.

I even removed the battery backup from the thermostat. Pointlessly.

The condenser is the last remaining thing with power, but boy is it fucking cold out.

>>1097247
Yes, verified the red wire is providing the correct 24v. Incoming power is correct.

ANYTHING that is an option doesn't exist.

>>1097243
If that were the case, I should have 16V to anything else after the transformer, which isn't the case. My main issue is that I cannot figure out why the yellow to condenser, which comes straight from the thermostat, would be on the same potential as something completely unrelated.

In any case, when I figure it out, I'll post what I find.

>>1097252
I see a callout for Yellow but no yellow wire.
Control board diagram missing?

Right now the only thing I can think of is the relay is being used to source current and burning out the coil.

Double check that wire nut on the transformers brown lead. Make sure nothing has backed out.

I have to go. but post the model/make for your unit. that will help.

>>1097258
This.

Check transformer connections. Check the transformer itself. 16V is too low. Make sure input voltage is correct and that it puts out 24V.

Feeding too low an AC voltage to some devices can cause them to draw excessive current. This is certain for motors but might also happen with contactor coils, causing them to burn out.

I'd guess OP is using a digital multimeter and doesn't know about phantom voltage readings. It's a common problem with these high impedance DMM. If you have a 500k - 1m resistor try testing with it in parallel to the probes. If the voltage drops significantly then you know it's not really there.

File: IMG_20161211_163138.jpg (4MB, 3120x3751px)

4MB, 3120x3751px

Ohh Lord ohh jesus

File: IMG_20161211_163149.jpg (3MB, 3120x3667px)

3MB, 3120x3667px

>>1097380
Why has my capacitor been masturbating so much into my control panel?

File: IMG_20161211_163652.jpg (3MB, 3120x3191px)

3MB, 3120x3191px

Over 20 years of service. Looks like it's been nigger rigged repeatedly. Someone changed the contactor years ago and forgot to connect the wires properly.

File: assault and battery clamp.jpg (61KB, 700x489px)

61KB, 700x489px

>>1097382
>>1097380

Off hand I'd say that cap is ded.

oh, and YUUUUUUUUUUUUCK!
That goes into my cringe folder.

Many many things could be wrong, even the controller being fucked nine ways from sunday.

You have a long road to hoe there anon and at 20 years you might be better off having it replaced. Especially if the rest is as corroded as those pictures.

Caps fail, usually they just swell up but that looks like it might have shorted out and sploded.

Nothing much left to do but to turn off the power, take a ton of pictures, and start cleaning and redoing harnesses if they are corroded. Spray contact cleaner works well, but wear splash proof goggles or a face shield. The controller board may be ok if that's just dirt. It can be cleaned with toothbrush. Just remember where all the wires go. (that's why photos).

One other cause of caps (this case run/start) barfing is a motor that is also going out. Normally due to worn bushings/bearings. And at 20 years you are at that magic date.

I'm going to go throw up now.