That would be a nice idea if true.
Using a infrared at a register would be a preferred method.
I am looking for a basic clamp meter for residential electrical system diagnoses Mr.Bottger.
I have a limited electrical knowledge and want to start my education and business off with proper tooling.
I notice drop meters being used by experienced HI’s.
I noted accurate readings observed using digital and explanation to deficiencies as yours helpful in understanding residential electrical systems.
Thanks… Robert.
Stay with the known names fluke makes a might fine meter
Don’t see why not, many ways to skin a cat. I still like the amp meter and I take a pic of the amp draw reading as I started this post with and place it in my report no client can ever say I did not check the furnace. I also take pic of the supply air discharge temp in the heat and cool mode both gas and electric furnace and those pic also go in the report
BTW off topic I also use the amp meter with pic in the report of the main and sub panels after I have loaded the panels with in house appliances and lighting circuits.
I disclaim having any financial interest in the sale of any amp meters -)-)-)
I am on the Flir page now. Funny.
Thanks. I m off to the Home Depot today.
Thanks for your answer in #9
I don’t concern myself with a unbalanced load specifically…
Thanks
Bob -
As an ex HVAC guy, and IR guy using my IR at a register would not be a preferred method of doing what I suggested.
Charley,
I disagree that an OHM meter tells you nothing when both end of the element are connected to the circuit.
One simply have to turn the thermostat down or turn off the furnace breakers for a OHM meter to give you a proper reading for those elements (strips).
Outdoor sensor are usually present for electric furnace with 4 / 5 or more elements. It’s purpose is to activate those extra elements when temperatures gets very cold for improved comfort inside the home.
I understand your heat pump theory but we are talking electric furnace.
As for Bob’s comment, I agree that taking a temperature reading at return and supply should also give you a fairly accurate picture as to a properly operating electric furnace according to temperature rise reading (~15 degree F / 5 kw) much like my hand over a register.
Cheers,
Mr.Bottger
I agree with Marcel. I have started studying ohm and drop readings on a electrical system. Enough to get very basic,basics so I could understand more and be proficient in my analysis or electrical in HVAC system to start.
I could be wrong but Marcel does have a point if I am not mistaken.
You have to have an open somewhere for the OHM meter be it at the breakers or where ever one chooses or you will read resistance of the circuit. Make it simple leave the unit running and use the amp meter.
We don’t use outdoor sensors in this part of the world on a straight electric furnace we use a two stage thermostat we operate on one stage only unless the indoor temp falls and the first stage cannot keep up.
Using your hand to determine a properly operating furnace can get you burnt but it will be your wallet not your hand;-)
Most of our heat strips here are 5kw, and should draw about 15 amps. I can’t count the number of times I’ve found one or two strips not working in a 15kw system. Sometimes it’s a bad sequencer, sometimes the strips are burned, but either way they ain’t workin. Only time I don’t open them is when the cabinet is sealed with either silicone or West Va. Chrome. 
I need to find a smaller amp clamp like yours, Charley. Mine is a bit clumsy in tight compartments.
Smart man I like the way you think you will go far young man:D:D;-)
Smart man I like the way you think you will go far young man:D:D;-)
I don’t find a lot but some, just not a lot of electrical furnaces here when I do it makes me shine like a diamond in a goats butt:shock::shock:
Probably a bad choice of words on my part did not mean It could not be done IMO its just harder to check the ohm’s than amps. I always used a OHM meter when the circuit was denergized to where I could disconnet the circuit so there was no resistance from anything else
Perhaps to clarify my point here is a very crude electrical drawing of two elements and the breaker on the front of the furnace one being burnt out or open and the other element closed both elements are connected to the same breaker 240 volts between the double poles.
Turn the breaker off as indicated no power place the ohm meter any where you want to on both sides of the open heat element and due to the closed element you will get a reading in resistance that was my point with a amp meter it is so much easier than messing with ohm meter
Blaine/Charlie:
Where do you get the amp draws from??
5Kw/240v = 20.8 amps
15Kw/240v = 62.5 amps
Quite a few years ago, doing an inspection of electric furnace in July and found the plenum already warm…1- 5Kw element relay stuck on…the vendors did not know this!!
Brian,
How did you find out that the plenum was warm?
Was it first by using your hand (or IR thermometer) over a register or an amp probe inside the furnace with power still on…
Cheers,
Thanks. Excellent point.
I bought a MTP 3093 digital clip on amp meter.
Did not have the extra $100 to buy a Flir or Fluke.
It will all come in time and I will sell my start-up tools or pass them to employees.
I will get Roy Cooke to show me more this weekend.
Thanks Mr.Bottger.
Right off of the manufacturers sticker on the furnace. Most differentiate the draw between 208 and 240, and show what the draw should be at either voltage.
And yes, I wrote incorrectly. At 240, I’m looking for around 20a.
If the fan/blower was not activated the thermal over load which is normally 150 F should have opened
It was in a small basement mechanical room that should have been a bit cool. When I entered, it felt warm…as I approached the furnace and touched the plenum, it was warm.