Better pop quiz

[Snapperhead]

Newbies .... Walk up to OD unit and after checking current across the contactor terminals comming in you get 160 155 110 162 125 fluxuating all around on meter, checking line 1 to ground you get 120, line 2 to ground you get 40 volts.

Whats going on here ????




One for the Pro's .... walk up to a different unit , different neighborhood, and get 120 line 1 , 0 line 2 , go to main panel and get 120 , and 0 when checking to ground and neutral at MAIN breaker.

What tha hell ....

[FL.HVAC]

I don't really know whats with the tests. But for the second one possible bad breaker or only one leg total coming into the house. Had that at my house just 3 days ago. One leg burned up at the transformer on the pole.

Here is one for you,
Will a 240-24volt transformer convert enough voltage to pull in a 24 volt contactor if it is only getting 120 volts to the supply side of the transformer?

[Snapperhead]

What reading did you get from the other 120 leg when it was disconnected from transformer?

[Cooked]

............One for the Pro's .... walk up to a different unit , different neighborhood, and get 120 line 1 , 0 line 2 , go to main panel and get 120 , and 0 when checking to ground and neutral at MAIN breaker.

What tha hell ....

One possible situation is the electrician wired the main panel wrong. He got L1 on one breaker and L2 on the adjacent breaker. Happened to come across this, this past summer. L1 wired to 40 amp AC breaker and L2 wired to 60 amp electric range breaker. Both breakers on and 240V at outside disconnect. AC breaker off and range breaker on and only 120V at disconnect.

[Tommy1010]

Snap, is this a way to get answers to the issues YOUR having? lol

Im just asking cuz it said in your profile, your part time hvac...???

Plus you never even gave YOUR answer as to what YOU would do for the 1st test?

:whistle:...waiting still??? LMAO

Just jokin wit ya, but dam man..."what would snapper do?"

[Snapperhead]

One possible situation is the electrician wired the main panel wrong. He got L1 on one breaker and L2 on the adjacent breaker. Happened to come across this, this past summer. L1 wired to 40 amp AC breaker and L2 wired to 60 amp electric range breaker. Both breakers on and 240V at outside disconnect. AC breaker off and range breaker on and only 120V at disconnect. Thats funny because i've seen this too in a restaurant where the owner did his own wiring :gah:

But the answer i was looking for was what FL HVAC said ... and he got lucky enough to see it first hand 3 days ago.

There are fuses at the elec pole outside.

[Snapperhead]

Snap, is this a way to get answers to the issues YOUR having? lol

Im just asking cuz it said in your profile, your part time hvac...???? Been doing it part time for 9 years. I've seen a thing or two :cheers:





Plus you never even gave YOUR answer as to what YOU would do for the 1st test?

Im not going to just give you the answer without you first guessing there buddy.
I know the answer because ive seen it several times , do you ?

[Tommy1010]

Been doing it part time for 9 years. I've seen a thing or two :cheers:

I know you have..I can tell by the questions..lol


Im not going to just give you the answer without you first guessing there buddy.
I know the answer because ive seen it several times , do you ?

For this one, i havent even really read it. For the other one, I misread it, and actually didnt realize the part where you said..NOTHING was running. So I retract my answer from that one. LMAO...

:cheers:

[Bill Lee]

First of all, how do you check CURRANT with a VOLTMETER????????

For the first situation, I would say that the house has a loose neutral and that the VOLTAGE is fluctuating due to varing electrical loads within the house.

In the second situation, you have lost power on one leg of the 240/120 volt service to the house. You could also possibly read a lower voltage (leg to neutral) on the "dead" leg if a 240 volt device was operative and feeding through the device to this leg. However, in this instance, you would not read any voltage from the "hot" leg to the "dead" leg.

[Snapperhead]

First of all, how do you check CURRANT with a VOLTMETER????????

For the first situation, I would say that the house has a loose neutral and that the VOLTAGE is fluctuating due to varing electrical loads within the house. . There is no neutral in a 240 device.

And its CurrEnt

Ok how about Voltage and not current (amps).... but you know what i meant.




In the second situation, you have lost power on one leg of the 240/120 volt service to the house. Correct






You could also possibly read a lower voltage (leg to neutral) on the "dead" leg if a 240 volt device was operative and feeding through the device to this leg. However, in this instance, you would not read any voltage from the "hot" leg to the "dead" leg. Again ... no neutral on 240 , and if you had the problem i stated above , yes you would have voltage reading hot leg to hot leg, but fluxuating all over.

ALTHOUGH you would be correct in what you are saying though ""if"" one leg was dead in YOUR scenerio, there would be a reading of 0 across both legs.

The one leg Im talking about in the quiz has 40 volts reading on the (Multimeter) to ground , and the other 120 to ground, but fluxuating voltages across both legs.

BUT.... what i think you meant to say ... if you have a 240 volt system and you are checking power at the contactor with it calling , you will read 120 on both sides to ground because it going through the device, even if one leg is dead from the disconnect.

Unhook the wires from contactor and (if you lost a leg totally like say through a fuse) you will have one dead leg to ground reading 0 , and one reading 120to ground , and 0 across both.

[Redwood650]

Newbies .... Walk up to OD unit and after checking current across the contactor terminals comming in you get 160 155 110 162 125 fluxuating all around on meter, checking line 1 to ground you get 120, line 2 to ground you get 40 volts.

Whats going on here ????




One for the Pro's .... walk up to a different unit , different neighborhood, and get 120 line 1 , 0 line 2 , go to main panel and get 120 , and 0 when checking to ground and neutral at MAIN breaker.

What tha hell ....


First of all, how do you check CURRANT with a VOLTMETER????????
.'


That's were I was confused as well. So you were saying check voltage across the contactor right?

[Snapperhead]

I will admit, the places i've seen this problem has been where a store owner , or homeowner tries to do their own work and doesnt understand you must get everything tight when messing with electrical stuff, whether you rig it , or go by code, and make sure its water tight as well.

[xformer]

FLHVAC- "Will a 240-24volt transformer convert enough voltage to pull in a 24 volt contactor if it is only getting 120 volts to the supply side of the transformer? "
NO

[FL.HVAC]

That's what I thought until at my house the other day when I had one leg burned off at the transformer and only had one leg coming into my house. The contactor was pulled in with only 120 volts going to the AHU. Very ODD!!!

[Snapperhead]

Was that leg totally dead ? Did you have ANY volts to it?

A burnt wire can still pass current, just not the whole 120.

A wire that has a blown fuse at the pole .... not so much.

Maybe you have a 120- 24 transformer

[xformer]

Ive had 240/24 volt transformers with 200 volts applied that made relays/contactors chatter

[brijess]

I've seen more than one 240/24 transformer where Sparky changed the service and wired the A/H 115 volt. Not only did the fan relay and contactor pull in, the blower ran at part speed. we found the input voltage issue on the no cool/ pipes frozen call. therefore the answer to that question is yes.