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-   -   Roper Electric Oven Range Problem (http://www.diychatroom.com/f47/roper-electric-oven-range-problem-109679/)

mcnutty 07-04-2011 06:52 PM

Roper Electric Oven Range Problem
 
Hi,

My friend's Roper electric oven range just died last week, I am trying to fix it for him.

He bought the oven brand new from Lowe's barely six months ago, he didn't buy the extended warranty form the store and the manufacturer's giving him the runaround. Long story short, he's not going to get any help from them, and right now, I am his help.

Roper free standing electric range

Model: FEP310VQ

Voltage: 120-208, 60HZ

Symptom:
absolutely no heat from all 4 surface burners and oven.


I have two screw drivers and a digital multimeter, I also have the wiring diagram (unfortunately can't find it on internet).

I've spent a day taking the oven apart, exposing the wiring, disconnecting the infinite switches and taking measurements, so far I am at wit's end.

So I am hoping the more experienced member here can help me out.

I will just asking some questions if someone can clarify it for me, I'd be grateful.

1) Power source

The power socket on the wall is a 3-wire, reverse Y shape receptacle, the 3 power supply wires end up on the back of the oven as Red, Black, White lines.

My understanding is the white line is the ground, and the red and black lines are power lines.

My multimeter AC voltage reading between the lines are:
Red-Black: 107v
Red-White: 120v
Black-White: 10v

The label on oven says power source should be 120v-208v. So my 1st question is, does my power source sound right? or is it possible one of the "phase" has fused out?

2) there are 4 surface burner elements, one big one and three small ones. The three small ones all look decent and have no visible damage, their ohm reading all check out around 46 ohm, I've no reason to believe all of them are malfunctioning at the same time.

3) neither do I believe all 4 infinite switches are malfunctioning at the same time.

4) I disconnect the wires for oven, oven indicator, surface indicator, and 3 infinite switches, leaving only one switch connected.

If I take the burner element out and check the voltage between the contact points, it's 107v, as expected, same as the voltage between red and black wire.

But if I plug in the surface element, the voltage between red-black drops to 0, indicating a short circuit. Red-white: 120v, black-white, also 120v.

change to a different infinite switch, and different burner element, same story.


This is what really puzzles me: turn off the switch or take the element out, the voltage appear to be normal 107v; but once put the burner element in, we have a short circuit between red-black.

Also like I said earlier, I don't believe the burner elements are the problem because their ohm number checked out, and it's barely 6 month old, can't be all bad at the same time.

so what could be the problem? thanks !

AandPDan 07-04-2011 07:23 PM

You have a problem with the power to the range. I don't think the range itself is the problem.

It should show:
red-black 240v
red-white 120v
black-white 120v

Since you are measuring power at the outlet, check it at the circuit breaker. It could be the breaker failed or you have a loose connection there. You may have a loose connection at the outlet too.

mcnutty 07-04-2011 07:33 PM

Quote:

Originally Posted by AandPDan (Post 679863)
You have a problem with the power to the range. I don't think the range itself is the problem.

It should show:
red-black 240v
red-white 120v
black-white 120v

Since you are measuring power at the outlet, check it at the circuit breaker. It could be the breaker failed or you have a loose connection there. You may have a loose connection at the outlet too.

thanks for the reply, that's what I suspected. But that still didn't explain the "burner element wire in, red-black shirt circuit" problem.

Here's a recap of the problem that has been puzzling me:

I checked the infinite switch label. It does have a "240v, 4.4-5.8A" mark on it. Right now, I am measuring only 107v between the red-blue. But once the switch is turned on, and the element is put in, I would measure 0 voltage between red-black.

does it mean a 107v power input will somehow short circuit the switch? why is it only happen when the surface burner is connected?

hardwareman 07-04-2011 07:35 PM

appliance repair 101, always check incoming voltage. You could have saved youself a whole day of frustration.

AandPDan 07-04-2011 08:25 PM

Fix the power problem. You should not be showing 10 volts between the black and white.

This is not an appliance issue, or likely wasn't before.

mcnutty 07-05-2011 04:54 PM

Quote:

Originally Posted by AandPDan (Post 679903)
Fix the power problem. You should not be showing 10 volts between the black and white.

This is not an appliance issue, or likely wasn't before.

AandPDan & Hardwareman:

thanks very much for your help and advice. I have some good news to report. I checked the circuit breaker, it turned out one of them has jumped. I turned it back on, and voila, the oven is working again. So it is a power problem, as everyone has suggested.

Something I learned (again) from this little adventure:

1) 120-208Vac appliances will only take the 2 phases 208v power, it will not work under 120v.

2) I assumed all household power sockets are 120v/60hz, but a few of them are specifically 208v sockets for so called high-powered appliances, and they are specially shaped like 3-wire reverse Y or 4-wired.

3) 240v rated infinite switch will somehow short out between red-black line under 120v, maybe it's a bug, or a design feature but I will never find out.

Incidentally, My friend's got another Roper range of the same model that died, he bought it 12-month back brand new. I will check that one out too, let hope the problem is similarly simple and easy.

Thanks again for all your help!

AandPDan 07-05-2011 05:32 PM

Quote:

Originally Posted by mcnutty (Post 680310)
AandPDan & Hardwareman:

thanks very much for your help and advice. I have some good news to report. I checked the circuit breaker, it turned out one of them has jumped. I turned it back on, and voila, the oven is working again. So it is a power problem, as everyone has suggested.

Glad to have helped.

Quote:

Originally Posted by mcnutty (Post 680310)
Something I learned (again) from this little adventure:

1) 120-208Vac appliances will only take the 2 phases 208v power, it will not work under 120v.

In the US it's 120/240 vac single phase for residential. 3 phase used in heavy commercial, is 208 volts.

Quote:

Originally Posted by mcnutty (Post 680310)
2) I assumed all household power sockets are 120v/60hz, but a few of them are specifically 208v sockets for so called high-powered appliances, and they are specially shaped like 3-wire reverse Y or 4-wired.

Lots of larger appliances, electric ranges, cook tops. electric dryers, and electric water heaters are 240 volt.

Quote:

Originally Posted by mcnutty (Post 680310)
3) 240v rated infinite switch will somehow short out between red-black line under 120v, maybe it's a bug, or a design feature but I will never find out.

I don't think the switch is shorting out as such. I think you see the voltage go to 0 because there was a load on it and a high resistance in the feed. Could be a phantom reading with a digital meter.(causing the 10 volt reading).

Quote:

Originally Posted by mcnutty (Post 680310)
Incidentally, My friend's got another Roper range of the same model that died, he bought it 12-month back brand new. I will check that one out too, let hope the problem is similarly simple and easy.

Who knows, maybe it was the breaker all along. If it happens again, change it. They do get weak over time.

Quote:

Originally Posted by mcnutty (Post 680310)
Thanks again for all your help!



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