Should a meter leads act as a jumper

[fzr600r]

I was with the lead residential tech yesterday, helping him fix several leaks on a boiler when we discovered the aqua-stat and circulator motor were bad.
When he checked for voltage at the burner terminals the burner came on.
I told him this isn't correct. He said that some meter will do this.....I told him go get the field-piece of junk replace....I know the correct answer, just wanted to get everyone opinion....

[Reeferman]

I was with the lead residential tech yesterday, helping him fix several leaks on a boiler when we discovered the aqua-stat and circulator motor were bad.
When he checked for voltage at the burner terminals the burner came on.
I told him this isn't correct. He said that some meter will do this.....I told him go get the field-piece of junk replace....I know the correct answer, just wanted to get everyone opinion....


He best be hoping that he doesn't hook up to 460 or more.

[Refer-Madness]

I was with the lead residential tech yesterday, helping him fix several leaks on a boiler when we discovered the aqua-stat and circulator motor were bad.
When he checked for voltage at the burner terminals the burner came on.
I told him this isn't correct. He said that some meter will do this.....I told him go get the field-piece of junk replace....I know the correct answer, just wanted to get everyone opinion....

Wow, I can't say that I've ever seen a meter do that. What model Fieldpiece is it, and is his life insurance up to date?

[HVAC Teacher]

Never seen a meter do that! Not even the cheap ones. Probably just a coincidence.

[ricksdaname18]

Maybe a bad connection where he put the meter terminal?

[cep a/c]

I was with the lead residential tech yesterday, helping him fix several leaks on a boiler when we discovered the aqua-stat and circulator motor were bad.
When he checked for voltage at the burner terminals the burner came on.
I told him this isn't correct. He said that some meter will do this.....I told him go get the field-piece of junk replace....I know the correct answer, just wanted to get everyone opinion....


FZR600 you are correct, it ain't supposed to happen that way. I have never seen this. I predominately use fluke, but even cheap meters should not do this. If he continues to use this meter he should up his life insurance, It will help the wife and kids in the future.

[fzr600r]

Guys it is a fieldpiece 76... My fluke 116 didn't act like the fieldpiece.. I will never use enough fieldpiece again.

[andserco]

I believe it depends on what type of device you re checking, about 20 yrs ago I was in a computer room working on the ac units, when an electrician was working on the fire panel. He was checking out some circuits when...........all hell broke loose, he dumped $10,000.00 worth of halon...:eek:. First law in working in a comp room take the actuators off the top of the halon bottles....:rolleyes:

[jhthornt]

Digital meters have a front end based on field effect transistors that effectivly cause the leads to not load down the circuit. Analog meters don't traditionally have these FET front ends, and will load a circuit under measure.

The subject digital meter is defective, and dangerous.

[overhaul]

if you set a multimeter to amps and hook the leads in series it will act as a jumper. Many years ago remember doing this to set heat antisapaters on thermostats.

[ricksdaname18]

yea the meter I have will not perform this function but I believe the guy I used to work with had a uei meter that would do that. By the way I was curious on the formula used to come up with a certain anticipator setting on a furnace. I dont understand how reading a milliamp draw through controls on a furnace relates to knowing at what point to shut the furnace off to avoid overshooting the setpoint. My guess would be the gas valve and controls are designed in such a way that draws a certain milliamp value that would pertain to that particular setting. Is there a rule of thumb on this anticipator setting if you have non-OEM controls or no recommended setting?

[KCProTech]

I believe that you go by the amp rating on the gas valve itself. Its usually listed on the vale.

[dawgtchrr]

yea the meter I have will not perform this function but I believe the guy I used to work with had a uei meter that would do that. By the way I was curious on the formula used to come up with a certain anticipator setting on a furnace. I dont understand how reading a milliamp draw through controls on a furnace relates to knowing at what point to shut the furnace off to avoid overshooting the setpoint. My guess would be the gas valve and controls are designed in such a way that draws a certain milliamp value that would pertain to that particular setting. Is there a rule of thumb on this anticipator setting if you have non-OEM controls or no recommended setting?

Back in the day when we had real heat anticipators that were variable resistors the manufacturer determined how many amps it would take to heat up the bi-metal so it could fake out the T-stat and shut it off early preventing the "overshoot". It was important to know what kind of loss your wiring had going to your furnace and the amount of amps that control of that furnace used in its operation, so measuring was important. Today with Solid State T-stats its not important as these now use a programed sequence and are not dependent on the actual amp flow.

[dawgtchrr]

I've never seen one as the settings were "averaged" to the "typical" system by the T-stat manufacturer. Fine tuning was done as a response to customer complaints. Hence the arrows showing "longer" -- "shorter" on some anticipators.

[ricksdaname18]

Ok, so Im assuming some of it is just done by feel. Do digital t-stats compensate for this other than by selecting gas, oil, elec, etc.?

[jcon04]

i use a fluke meters and was working on a york, it would like the gas for heat and then go out. and keep doing this. hooked my meter up on the common side of the gas valve and the other lead to the frame and it would stay light. didn't think this could happen. good thing it's low voltage.

has anybody had this happen to them??

[steve3871m]

So where the burner terminals 24v? Some lower end DMM's will have a low impedance and can send a signal out from the battery.

Not familiar with the Field Piece. I use Fluke 87V hi impedance meter.

[spellman]

overhaul is right if you plug your leads into the amp spot on your meter it will act as a jumper it should be fused but if you hit high voltage with it your meter can explode
so pay attion when u let someone else use your meter

[hearthman]

Go to the Fluke sight and download the technical piece or get the DVD on meters. I went to a Fluke class and saw the rep. plug a meter into 110vac and switch from volts to Ohms and back while the leads were still attached and it didn't blow. If it tried to, Fluke has fuses to protect you. That and it's rated Cat III. He also dropped it a few times with no ill effect.

The 116 is a great meter. Great accessories. Great support.

Hearthman

[btcstudenthvacr]

Any and nearly all meter's sold today are fused. Its easy to jump to contacts together with a probe if your not careful. Fluke meter's and Fieldpiece meters are both tested and rated. In the end it's up to the user to be safe...