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Loose wire on rheostat indicator light + rocker not illuminated

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  #1  
Old 05-14-18, 07:24 AM
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Lightbulb Loose wire on rheostat indicator light + rocker not illuminated

I had a (quite old but good) column oil heater with a broken rocker on/off switch, which I've managed to replace.

I'm now getting heat !

_________________________________
I have two final problems:
1) The rheostat indicator light is not going on and it has a loose wire (see pics)
2) The new rocker switch is not illuminating.


________________________________________________________
PROBLEM 1: Rheostat indicator light

You can see here that connected to the indicator light is a WHITE covered cable and the GREY loose wire (these pics are also ATTACHED):
https://drive.google.com/open?id=1Cz...f9d_CnVQfE10Tu

The WHITE CABLE goes to a piece that seems to be connected to both:
- the black cable
- the heater itself via a separate cable:
https://drive.google.com/open?id=125...gmCkBLq3dGrh4Z
and
https://drive.google.com/open?id=1_C...uB6pFcIw76VHqf

Where is the grey wire likely to go?
How can I get the light to work? (Of course it could just be broken)


I read something that might relate to both problems: that an illuminated SWITCH (at least) needs to be earthed in order to go on...
_________________________________________________________

PROBLEM 2: Illuminated rocker

How could I get this to light?
Note:
1) You can see it in the pics
2) I only have two cables at the moment, because the old switch didn't light up. It only had two terminals. The new one has three.

SPECS:
SPST
15 amp
250 vac
T120
three terminals.

Replacing a 10 amp, 250 vac with TWO terminals

(The heater is quite old - it was actually made in England! A Dimplex)
_________________________________________________________
PROBLEM 3:

How can I (use my multimeter to) test the appliance to make sure it (including the cover) is safe once I'm done.

_________________________________________________________
Most grateful for any help because:
1) This heater has served me well
2) I don't want to add more waste if it can be fixed, and I'm only a student
3) I see 'new' heaters being thrown out all the time

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Last edited by PJmax; 05-14-18 at 09:03 AM. Reason: added two labeled pictures
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  #2  
Old 05-14-18, 09:05 AM
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Welcome to the forums.

Make sure that illuminated switch has a 240v lamp. The switch contact and light ratings can be different.

I'm on the road but will be back shortly to help you further.
 
  #3  
Old 05-14-18, 04:17 PM
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Ok..... copy of the drawing below.

Connect the loose lead from the power light (ZZ) to the thermostat terminal (ZZ) that goes to the heating element. This light will come on only when the element is heating.

Connect neutral to the third terminal on the switch. Make certain the light in that switch is rated for 240vac or it will explode. This light will come on when power switch is turned on. If the light is working backwards.... switch the two wires that are currently on the switch.

Your unit shows a third/ground wire. Using your ohmmeter.... check from the third pin (ground) of the plug to the metal case of the heater. You should measure a dead short... 0 ohms. That is what you want. That confirms the safety ground is correctly connected.

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  #4  
Old 05-14-18, 07:52 PM
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Wow !!

Thanks so much - you guys are awesome !

This is incredibly helpful and is much safer than me googling too.
(If I'd followed Google I would have been 'earthing' that grey cable by connecting it to the case (somehow) lol.)

__________________________________________________________
Just to clarify a couple of things
(I've put numbers on my questions so you can save time by referring to them )

_____________________________________________

1. Re ZZ wire
(See pic 01)


1a) Can I simply unscrew that screw a bit and wrap the exposed part of the grey wire around the connector, without adding an additional piece?

1b) I notice it's quite close to the copper-looking housing - do I need to avoid that?

_____________________________________________
2. Re checking ground
(see pic 02)


2a) So I'm checking resistance/ohms from the lower prong (earth) of the plug that goes into the wall, to any part of the case?

2b) BTW, what level would you recommend for that?
(Mine doesn't beep but I've got 200, 2000, 20k, 200k and 20M)

2c) Being that it's only resistance, I assume it doesn't matter which thing the BLACK probe goes on vs which thing the RED goes on?

SIDEBAR (if you have time):
I noticed that when I tried this technique recently, putting the probes on the screws you see in the pic below (see last pic: where the power enters) and on the matching prongs of the plug, the numbers were all over the place: from zero to various numbers. That doesn't seem very consistent...which concerned me about the accuracy of this method...

2d) What was going on there? Was it just a matter of imperfect contact?

_____________________________________________

3. The Switch light

The side of the switch has the following written on it:

20A 125 VAC
15A 250 VAC


On the right hand side of that:
T120

3a) Does that sound like it could deal with the current?

I only have one spare neutral cable and it's going into the thermo-indicator-light (see pic 03).

You can see where that goes (last pic: 04) (NOTE: It is at THESE screws that I was checking resistance compared to the plug prongs...)

I'm thinking maybe we should put this one in the too-hard basket - it's not absolutely necessary to have it light up when on.

3b) However IF YOU HAVE TIME I'd be interested to hear how I could do it....

____________________________________________________

Thanks again ! I was not going to throw out this heater no matter what, so you actually giving me the right info is helping me fix it safely and effectively.
 
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  #5  
Old 05-14-18, 07:55 PM
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Hey Pjmax - you bloody legend (as we say in Oz!) - feel free to save your valuable time by just answering even just like this where appropriate:


1a) yes
1b) no

etc !
 
  #6  
Old 05-14-18, 08:13 PM
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1A and B - yes you can wrap it around there. That screw terminals must remain tight. If the wire is not staying there you may need to use a crimp terminal.

2 - use the 200 ohm scale. Polarity makes no difference. You want to measure less than 1 ohm. The closer to 0 the better. You want the power cord ground to be at the same potential as the case. Measuring low resistances requires good connections.

3 - The T120 would suggest a 120v lamp. You'd need to check with where you got it from.
That only needs a neutral connection to light up. You can connect an additional wire back where the power cord junction block is.

If you connect the ON light where I told you.... ZZ..... it will only come on when the heater is actually heating. You may want to connect to the other side of that thermostat so that the light comes on whether or not it's actually heating.
 
  #7  
Old 05-14-18, 08:30 PM
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Wow man, you must be so happy to have all this knowledge - thanks massively for being so kind as to share it with me!

(As currently a student, I could never afford an electrician here in Australia, so if we weren't doing this, I'd be v reluctantly throwing this item out - more WASTE!. Besides: what about the book 'Shop Class as Soulcraft' lol?)

RE the switch light:

1. I will indeed check with the store (Jaycar here in Australia - they're pretty hopeless sometimes - and understaffed)

2. I had a feeling I might be able to connect it to the thermostat actually! However:

a) I will show you a pic of where that non-ZZ connector goes, just to be sure (upload shortly)

b) ALSO: I noticed you marked the UNUSED terminal of the switch NEUTRAL. However I was told by the store guys that it is GROUND. It is also GOLD-colour, whereas the other two are SILVER. Apparently in Oz ground is usually GOLD. They are marked 1 and 2, it is marked 3. Is there a contradiction?
 
  #8  
Old 05-14-18, 08:39 PM
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Ah of course, the non-zz terminal simply connects to the switch terminal...

If I were to do this, I guess I would buy a crimp terminal (to go on the switch) and on the other end, either:
- a bare exposed wire (second best)
- or perhaps a u-shaped crimp-connector (best)

I'm assuming I just need a 240 volt wire
 
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Last edited by Tim in Oz; 05-14-18 at 09:42 PM.
  #9  
Old 05-14-18, 08:57 PM
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Regarding switch gold terminal and rating...

You can see here the different colours of the terminals that I'm concerned about (as mentioned above): you said it was neutral but other people have said GOLD is GROUND in Australia.


Re: the lamp rating:

This product is probably the same one as I'm using (except it says '240' instead of 250 because people in Australia usually just say 240v)

Anyway, I just described the switch to them in detail:
20A 125 VAC
15A 250 VAC
T120
and the guy said that since the switch itself is rated for 250 volts (up to 15 amp), the light is also rated for that.

(They said the reference to 125 VAC is to say that if you were using that voltage, the switch can handle up to 20Amps.)

https://www.jaycar.com.au/rocker-swi...40vac/p/SK0979
 
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Last edited by Tim in Oz; 05-14-18 at 09:44 PM.
  #10  
Old 05-14-18, 09:41 PM
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BTW:
Sweet success on the light btw ! As you can see...

I just hope I wired it using the best route - I will happily change it to the alternative (going underneath) if you think that's better (safer)?
 
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  #11  
Old 05-15-18, 01:57 AM
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Looks good.

The odd colored terminal is neutral. The same neutral that your power light is connected to.

Ultimately neutral and ground are connected together in the service panel but ground is never used to carry current.
 
  #12  
Old 05-15-18, 04:47 PM
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Talking

Pete you are my Yoda !
 
  #13  
Old 05-15-18, 04:52 PM
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Hey I've been inspired by your sagacity to start learning from this !
(From the famous non-profit Khan Academy)

https://www.khanacademy.org/science/...al-engineering

I've been liking the idea of learning something - but wondering: but what could I learn that is actually USEFUL?
Now I know !
 
  #14  
Old 05-15-18, 05:42 PM
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Fly me down there. I'll teach you all you need to know. Name:  BIG_THUMB.jpg
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  #15  
Old 05-16-18, 03:26 AM
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Haha well if you're ever in Melbs I'll buy you a beer or three !
 
  #16  
Old 05-16-18, 03:45 AM
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Actually I have another small Q lol !

At the electronics store I asked for 240v rated cable and they gave me some of this stuff:
https://www.jaycar.com.au/fig-8-whit...metre/p/WB1560

240 v power flex figure 8 wire
with two cores
Rated 7.5 amp (which I've just realised might be a worry?)

"suited for lights and general 240V work not requiring an earth"

I may not actually wire up the switch permanently, but I wouldn't mind at least testing it.
But I was wondering:
do I use both cores?

_________________________________________
Wiring it up properly could be more expensive:
* About $6 for the crimps:
- push-on
- fork
...which I have to get from another store to get 240v rated ones...

* BUT ALSO $6.50-$8.50 for woven fibreglass sleeving, suggested by store dude...
I am wondering if this is necessary.
I pointed out that the grey wire didn't have it, but he (cleverly) noted that the grey wire could have been added later by an amateur!


3mm $6.50
https://www.jaycar.com.au/vidaflex-f...eving/p/WS5504

3.5 mm $8.50
https://www.jaycar.com.au/vidaflex-f...-pack/p/WS5506
 
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  #17  
Old 05-16-18, 09:07 PM
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You only need one piece of wire. It can be very thin. #18-#20 is fine.
It's only for the light in the switch.
This looks like our #16 which is also ok....
https://www.jaycar.com.au/blue-extra...metre/p/WH3052

For testing..... just connect the wire in place. If it works ok.... add that fiberglass protection later.
 
  #18  
Old 05-16-18, 10:51 PM
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Is the one I have okay though? (for testing only. I'll buy the one above if I'm going to do it permanently)

If so: do I have to only use one wire or can I use two anyway?


(NOTE: I'm temporarily running it from the unused switch terminal to the closer side of the thermostat - ie opposite to ZZ)
 
  #19  
Old 05-17-18, 06:38 PM
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Look back to your first post. I labeled the neutral where the power cord connects. That terminal on the switch needs neutral to light up. You may be able to add your wire right at that terminal strip.

As an aside..... those terminal strips are commonly used in heaters. It's very important that the screws are tight to keep the connections from overheating.
 
  #20  
Old 05-17-18, 09:34 PM
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STRANGE RESULTS of test!

(I'm ready to close her up! I won't bother with the light but I want to make sure these results don't indicate anything untoward.)

1. When wired up as it is now (see pic):
the light came on when it was OFF, but not on.

2. But when i swapped the two (main, non-light, silver) terminals around on the switch:
light failed to come on in either position.

Both times the red thermo light came on and it heated.
 
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Last edited by Tim in Oz; 05-17-18 at 11:34 PM.
  #21  
Old 05-19-18, 12:16 AM
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I don't understand why those results obtained. (To sound like a British historian lol).

Does it indicate anything of concern? (To sound like someone from 'Yes, Minister' !)
 
  #22  
Old 05-19-18, 09:46 AM
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Did you read post #19 ??

The third switch terminal NEEDS neutral. You have it connected to a hot location.

Let me explain further..... on your switch there are three terminals.
One is power in. One is switched power out. One is neutral for the indicator.
The indicator is connected inside the switch to the switched power terminal and the neutral terminal.
 
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