A meter "veer"...

[Brian Roth]

Check the grounds in the entire car. "Haunted" cars almost always have ground problems. Start with the ground loop that connects the motor block to the chassis.

Oklahoma is one of the states that uses salt in the winter?

Okla does use salt, but not that often. And Mom wouldn't drive in any sort of bad weather.

Also thanks to Scott for the suggestion.

Bri

 

[Brian Roth]

Mac, that Uni-T looks interesting, Thanks.

Bri

 

[scott2000]

That uni-t looks similar to this one I picked up earlier last year for the extra k meter temp leads to goof with my ac.. look like maybe different specs..
Trying not to like it but haven't had a reason to yet... Haven't hardly used it though outside of my air conditioning tasks...
https://www.amazon.com/dp/B07Z398YWF?ref=ppx_yo2ov_dt_b_product_details&th=1

 

[Brian Roth]

While I seldom mess with temperature measurements, my Fluke (bought years ago) came with this accessory:

https://www.fluke.com/en-us/product/accessories/probes/fluke-80bk-a
Besides some occasional checks of stuff like heatsink temps, I use it during the air conditioning season to check the differential temps between the supply and return vents in this central HVAC system here at Camp Chaos. Also handy to "trim" the room temp offset menu setting with the so-called smart thermostat; stat is offset trimmed by a degree or two to match the Fluke thermocouple.

Bri

 

[scott2000]

Nice.
My old neighbor across the street was a big hvac guy who used to help us out a lot. After he moved, although he was always coming by to help and still does, I tried learning as much as I could last year when my delta was too high......as were my power bills. About 25* iirc...

Cleaned the inside coils twice and still no dice. Turned out I needed a third attempt with some compressed air. Crazy how much stuff was still in there.

About 5 years ago, we had the filters installed at the returns downstairs because it's supposed to be good to help with airflow since having a filter right at the coil can get restrictive easier. Guess it keeps ducts cleaner too...

Only thing I hadn't considered was that all that return ductwork to the handler was dirty from the decade prior of having the filter directly at the handler. So I was pulling filtered air through dirty ducts right to the handler for many years....Doh....filters are back at the handlers for now...

The k meter leads are great for checking the subcooling . Really get the refrigerant dialed in....

I was reading that sometimes the hole in the wall behind thermostats where the wires come in can throw off the thermostat ... Could make sense I guess...

 

[JohnRoberts]

Nice.
My old neighbor across the street was a big hvac guy who used to help us out a lot. After he moved, although he was always coming by to help and still does, I tried learning as much as I could last year when my delta was too high......as were my power bills. About 25* iirc...

Cleaned the inside coils twice and still no dice. Turned out I needed a third attempt with some compressed air. Crazy how much stuff was still in there.

I just cleaned my outside compressor coils with foam and a water hose... they specifically advise against using a pressure washer

JR

About 5 years ago, we had the filters installed at the returns downstairs because it's supposed to be good to help with airflow since having a filter right at the coil can get restrictive easier. Guess it keeps ducts cleaner too...

Only thing I hadn't considered was that all that return ductwork to the handler was dirty from the decade prior of having the filter directly at the handler. So I was pulling filtered air through dirty ducts right to the handler for many years....Doh....filters are back at the handlers for now...

The k meter leads are great for checking the subcooling . Really get the refrigerant dialed in....

I was reading that sometimes the hole in the wall behind thermostats where the wires come in can throw off the thermostat ... Could make sense I guess...

 

[Brian Roth]

@scott2000

Camp Chaos here in Salina is an older frame house....someone told me it was built post-WW2, but some of my searches say 1920's.

Anyway, it obviously had a floor furnace years ago (someone did a very decent job of "patching" the hardwood floorboards in the living/dining room area). In that same general floor area is the single sheet metal return dropping straight down into the basement. There, it makes a quick turn into the filter "chamber" on the way into the bottom of the air handler. IE....upflow HVAC unit that seems a bit "elderly"...I have to light the pilot light every fall/shut down the pilot in the spring. Supply ducts are multiple round sheet metal elements crossing overhead in the basement.

Pulling off the return register and peering down, it's kinda funny....the walls of the sheet metal return duct look "fluffy"! My roomie/best friend and I are trying to concoct the best method to clean the walls of that return. Something like a Shopvac with a VERY long (10 foot) wand...lol.

The "smart stat" is mounted on a new interior wall when the Camp was mostly remodeled 10 years ago, so no air leakage there.

Bri...and I did yet another veer on the veer on the veer....

 

[Brian Roth]

Trying to undo my veers...back on topic for a decent ammeter!

Spent what few brain cells I have left <g> to recall specific reasons I ever wanted/needed/used a clamp meter in the past decade or three. Very seldom....

1. Clamp around AC wiring in a breaker panel to check/verify current draw.....almost always around the wire exiting from a single 20 Amp circuit breaker. I'm not an electrician, so current flow (hundreds of amps?) from the power utility into the entire breaker panel would be usually a point of curiosity.

2. Measure AC current into a single device, or often into a "power strip" feeding multiple gizmos in a rack. Hence my DIY "break out" with male and female Edison connectors at each end and a small length of insulated conductors in between.....in Post #10, Duke showed his version.

3. Measure the DC current in some sort of power supply system for a desk, without having to physically chop into the DC power cable. My EXTREME example was the 5V busbar in a Neve Capricorn DSP rack....hundreds of amps...that desk is long gone in my world. More reasonable would be well under 20 Amps.

4. And try to troubleshoot the electrics in an old Passat <g>.

I like the physical size and price of the UNI-T Mac mentioned in post #17. Now I'm fussing my feeble brain about some of the ergonomics with the readout being "sideways" in the housing.

SH!T.......killing brain cells about details for a seldom-used tool here! lol

Bri

EDIT....from 10+ years ago, I recall trying to determine why a 20A breaker feeding a control room of equipment would randomly trip off. It was what would be called a higher-end Podcasting facility in these days, and was built in an office building. I had carefully calculated...then measured...the required power for the entire control room with all the audio and video gear. Well under 15 Amps and I specified a dedicated 20A circuit into two or three outlets in the new construction.

I left my "Amprobe clone" hanging on the #12 AWG wire exiting the (supposedly dedicated 20A breaker) for hours and regularly went back to check it. Right place....right time....14 Amp draw jumped to over 30 Amps just before the breaker tripped before my eyes.

Called the electrical contractor back. For reasons unknown, that "dedicated" circuit also fed the ceiling lights of the conference room in an adjacent suite in the building. So, if they lit ALL of the incandescent fixtures (several wall switches) in their room for a meeting....boom....breaker trip. Once I figured out what was happening, I chatted with the folks down the hall. They had also been perplexed and reported their outages to building maintenance guys who flipped the breaker back on at the panel waaay down the hall.

Bri

 

[scott2000]

I just cleaned my outside compressor coils with foam and a water hose... they specifically advise against using a pressure washer

Yeah the outside condenser was pretty easy with just cleaner and water hose. The inside units are upstairs so I tried first with cleaner and a pump up sprayer. They looked great then but I still had no temp diff change. So then I put one of the garden hose to sink adapters on and tried the cleaner with a garden hose with a bit more volume and pressure. Had to put a just barely fitting concrete mixing tub in the return area to catch all the excess water. Then they looked really clean. Lot of stuff came out. But the change was only a degree... ever step on a hose sprayer and the water shoots out all over the place until you can get to it? Don't do that upstairs inside...lol

Some old carrier instructions and a video online said to use compressed air...

I took a phone video close to the coils and could see tons of stuff jammed in between all the structures in the coils. So I did the compressed air... Maybe 40psi at the gun... I can't remember but it was pretty low.... I was covered in splattered crud by the end of it and my temp differential dropped almost 5 degrees after...

Removing the coil to take outside for cleaning would have been best but that wasn't going to happen...

Regarding circuit overloads....We have some pretty extreme voltage drops with long runs of circuits inside...Too bad 12/2 isn't used in these scenarios.. Seems like it would be better...