Coleman Fresh N Vac Blows 24 V Transformer.

[Earl Weiss]

Unit wasn't working. Found no output from 24V Transformer. Replaced. Worked for 1 minute, blew the timer and smoked the transformer.

Replaced timer, replaced transformer. Worked 1 minute and blew transformer.

Replaced both wiring harnesses to timer. They were old. Figured it would be a miracle if it worked. Lots of wires. Replaced transformer. Worked for one minute and smoked transformer.

So, it would seem there is a short somewhere on the 24 Volt side.

Most Likely culprit? What to test?

 

[Tom Thumb]

Check 110volts wires coming into vac, they have a habit of melting together and will short out .

This has happened several times here.

 

[Earl Weiss]

I would think that if the 110s melted together the 110 breaker would trip.

 

[JGinther]

I would disconnect the ground wire for the timer, hook up an ammeter on the 24 VAC, and turn it on for a couple of seconds and make sure you don't pull over the rated amperage of the transformer. If I remember right, there is a small diode on the ground circuit that can go bad and pull all of the voltage to ground. If the transformer isn't over-amping, touch the ground to the stainless frame of the machine and see if it spikes. If you don't have an ammeter, you can use the wafting of smoke to your nose method.

 

[Ghetto Wash]

Before you do anymore testing, put a fuse in line with the transformer. Quit spending money on transformers.

 

[Earl Weiss]

Before you do anymore testing, put a fuse in line with the transformer. Quit spending money on transformers.

How many Amps? Can I get it at Radio Shack?

 

[MEP001]

I'm wondering if your transformer isn't undersized, or if one side is grounded when it shouldn't be. I'm not very familiar with Coleman equipment in general, but typically with 24V AC running off 110-supplied transformers, one leg is 24V and one is neutral. If the 24V neutral is combined with the 110V common or grounded to the unit, the transformer wiring has to be right. I suggest this because if it were just wired wrong or if there was a dead short, the unit wouldn't have worked at all before the transformer blew.

A 1-amp fuse should be big enough. Radio Shack's inline fuse holders are pretty poor quality (Don't ever use them for vac motors), but for low voltage it will be fine.

 

[Stuart]

You might look for a resettable pop out breaker instead of using the barrel breakers which you will have to replace with each blow-out.

I would start by disconnecting pretty much everything in terms of wiring and start from the ground up. turn power on and see if you have 110 V. Power down and hook up the transformer and pwr up to see if you have 24v. pwr dn and hook up the coin acceptor and timer but disconnect the load wire and pwr up and see if acceptor works and turns on timer. I think you see where this is going. Hope you are familiar with a voltage test meter.

BTW what is the VA (voltage amps) on the replacement transformer? I pretty much us a 110v to 24v / 40VA transformer on all my vacs. This will take care of the timer, relays, coin acceptor with plenty to spare. Just because it states a 110v to 24v does not always mean it is a replacement for what is in your equipment.

 

[Earl Weiss]

Same issue with another Vac Starts. Call in tech from Coleman distributer. His diagnosis is wires / conduit issue underground causing ground to be energized.

Call in to electrician now to confirm and trouble shoot area of problem and correct. Apparently severe cold this winter has lead to this issue in various areas. Moisture in conduit freezing, and causing breaks and shorts.

FWIW neat install of conduit / wire running under the islands now becomes a headache if not a practical impossibility to correct.

 

[JGinther]

I am going to go out on a limb now and say that you are being accidentally mislead. While I am sure that everyone that came by is trying to help, I don't think they have figured out the problem. The claim about the ground being energized is pretty much impossible if the the neutral bar and ground are hooked together at the main electrical panel like they are supposed to be. You would have to have a break in the conduit, a ground wire completely broke off, a hot wire sheathed and touching the vacuum island side of the broken ground wire, and have a bad main breaker. There is almost no way that happened, and certainly no way that happened twice.
In the cobwebs of my memory, I have fixed this problem before. So before you spend any more money, let me check into a vacuum like yours and clear the fog in my head... I am 73% sure there is a component that is installed on the ground wire coming from the timer....

 

[JGinther]

Ok. I believe these are your problem (see right side terminals). Follow the white/black wires from the timer. You can get them from an electronics supplier or from coleman, but i believe you can also just cut and cap them with no issues (cant remember for sure though)

 

[MEP001]

I have to agree that it probably isn't underground wiring, not if you're getting 120V to the vacuum. Feeding voltage to the ground wire would almost certainly cause the breaker to trip if it didn't electrify the whole vac and shock someone.

 

[Ghetto Wash]

If it is your underground wiring, don't sweat it. I have a couple spots there the conduit is broken or separated and stays full of water. I end up having to run new wire every 5-7 years. A lot easier and less expensive that removing concrete and replacing conduit.

I have plans to replace the wires with something that is ok for direct bury, but every time they go bad I'm in a hurry to get back up and running and don't spend the time looking for better wires. I just put normal (THHN) wires back in.

 

[Earl Weiss]

Ok. I believe these are your problem (see right side terminals). Follow the white/black wires from the timer. You can get them from an electronics supplier or from coleman, but i believe you can also just cut and cap them with no issues (cant remember for sure though)

Color me dense. What am I looking at - Those little cylinder things?

 

[JGinther]

Yes. If you follow the black and white wires (usually twisted together) from the timer, they will route to those pull down resistors. From the resistors, they connect a wire to the vacuum chassis. When they fail in the closed position, they will route voltage to ground. Since one of the secondary (output) legs from the transformer is grounded, it will fry the transformer (or 7 or 8 of them). Thing is, I think it will work just fine without the ground drain, so I would try just cutting the wires and capping them first. I always thought you were supposed to keep the ground out of electrical design, and the ground was only to be used for safety and spike voltage shunting (exception automotive). If you were to hook up a brand new vacuum from Coleman to a GFCI, I think it would trip...

 

[Earl Weiss]

So, electrician comes to check power / short in conduit.

Finds vacs are now supplied with 220V.

Apparently the Vacs were blowing breakers and unbeknownst to me my manager found the bars burnt where the breakers attached in the box so bought new breakers and put them in an available open spot. How that spot supplied 220V I don't know.

Now I will have to see if anything else is fried.

 

[I.B. Washincars]

How that spot supplied 220V I don't know.

Been there, done that. You probably have the same scenario that I have at one of my washes, a wild leg. I don't know how it all works, but one bar in your panel will be 220V or whatever. If yours is like mine, every 3rd breaker in your panel is supplied 220V. I got lucky and caught it right away and didn't burn anything up.

 

[Washmee]

It's called the "kicker leg" in a 3 phase Delta system. I think it is designed to assist motor starting on 3 phase the way a capacitor assists a single phase motor.

 

[JGinther]

There's the rest of the story! Now if you want your place to be up to code and prevent another disaster or possible electrocution, you should go to the electrical supply house and get a premade sign that says b (should be b) phase wild leg ( it also should be an orange wire ). If your power is 240 v, you will have a wild leg. Just an fyi, only double pole or triple pole breakers can ever use those spaces.

 

[2Biz]

I have wild leg 3 phase in my ER, although it only runs my pump stand. I also have a single phase 220v panel. The funny thing (or not so funny) is I have two meters and pay two electric bills. Both meters are fed from the same supply wires from the transformer! The wires are split ahead of the mast and feeds both meters. The electric company has a good thing going!

The "Wild Leg" 3 phase I have has (2) 120v legs with a 208v center leg. The way it was explained to me, it was developed to give a business the option to have single phase 120v, single phase 220v, single phase 208v, or 240v three phase. The 208v center leg was used for high power lighting. The only way to find the center 208v leg is to check each phase to common or ground. I would think it would be easy to get confused or maybe making a mistake if you don't know what your doing in a 3 phase panel. Maybe that's why I have a single phase panel and a 3 phase panel. It keeps everything separate. When I first bought the wash, the electric had me scratching my head. It was pretty confusing.