dcsimg
Self Help Forums

Go Back   Self Help Forums > Repair > Electrical - Existing Home
Register FAQ Members List Calendar Today's Posts

Electrical - Existing Home Electrical Repair / Remodeling Ideas / Problem Solving Solutions

Reply
 
Thread Tools Display Modes
  #1   IP: 69.131.226.47
Old February 2nd, 2007, 08:37 AM
epojr epojr is offline
Junior Member
 
Join Date: Jan 2007
Posts: 25
Default Dryer heating on 120V only

I think I have gotten the dryer receptacle that i previously asked about working properly now, everything checks out correctly in the recep itself and the grounding wire. However, I am afraid that the dryer heating element may have been damaged by what sounded like an arc in the recep box the first time I plugged it in. (That arc was the reason for my first post) My wife dryed several loads yesterday and she says it took about 50% more time than normal to dry them. Is it possible that one of the dryer's internal wires, either red or black, that feed the heating element was burned out or knocked off a connection point by the arcing at the dryer recep? If so, wouldn't that cause the element to operate on only 120V instead of 240?

If I test the red and black wires on the dryer hookup panel for continuity to neutral will an open circuit indicate a break or a disconnect in that feed wire? I guess that's a dumb question, but I don't fully understand how 2- 120V feeds combine to make 240V. I have read the explanation and seen the diagrams of how 2- 180 degree out of phase alternating currents fit together to double the voltage but it's still Greek to me.

Another question just came to mind. If the dryer is unplugged a continuity test may not work because the switch that turns on the dryer motor and element would have to be in the on position to complete those circuits and it's controlled somehow to automatiacally shut off when the door is opened. I assume that switch is activated electrically so if the dryer is unplugged it probably won't open and close the heating element circuits. Does any of that make sense?
Reply With Quote
  #2   IP: 69.254.246.210
Old February 2nd, 2007, 11:14 AM
Roger's Avatar
Roger Roger is offline
Senior Member 'Self Help Master with Distinction'
 
Join Date: Aug 2004
Location: Kansas
Posts: 1,645
Default

I've read your other post and would have to come to the conclusion that the arcing was a result of your installing that ground wire pigtail. Not that it was wrong but something shorted to that ground wire when you put it all back into the box. Normally the breaker should have tripped.
The other thing I see that I want to ask is that you said the new dryer 4 wire cord had the ground wire on a terminal. Usually the ground does not connect to the terminal block of the dryer. It will connect under a green screw that is fastened to the frame. Maybe thats what you meant.
As to the neutral terminal and removing the the bonding strap. Look at the neutral terminal (the center one between the two hots). There will be a small white wire connected to the terminal with the white wire of the cord. Then there may or may not be a metal strap connected there but there may be a green wire with yellow stripe. Some manufacturers use a wire and some use a metal strap. A metal strap is usually very short and fastens to the metal frame of the dryer close to the neutral terminal. If they used a green wire or green with yellow stripe wire follow it to where it connects under the green screw on the dryer frame. Disconnect either wire or strap from the frame. You can fold them back and connect the end that was fastened to the frame to the neutral terminal ...in effect just making a loop...or remove them completely. the green of the new 4 wire cord will go to the green screw threaded into the dryer frame. Just wanted to clarify what Mark mentioned earlier.

As for wondering about why the dryer isn't heating properly or some other problem you will have to make some tests. You need a voltage tester that measures volts ...which it sounds like you have. You need to test between the two hot wires terminal screws on the back of the dryer. Touch one probe to each screw you should get 220 to 240 volts. Each hot wire to the ground or neutral will result in approx. 120 volts. Normally the heating element is all that requires the 220 volts with every thing else including the motor 120 volts. If either hot wire does not show voltage to ground then one leg of the supply has failed. If you have voltage on both hot wires tested individually at the terminal block of the dryer to the neutral terminal or ground then your heating problem is internal to the dryer or a venting problem like a blockage has occurred. You know that you at least have one leg working because the dryer runs so you need to determine if both legs are present at the terminal block of the dryer. Be careful making these tests. Then if you have access to the element check the voltage at the two terminal screws there. Again be very careful

I seem to recall you said the dryer had been working fine then this problem occurred with getting the clothes dried. Check your venting for any blockages or pinched ducts. Also the lint filter needs to be clean.

Check back with us on what you find.

Roger

Last edited by Roger : February 2nd, 2007 at 11:16 AM.
Reply With Quote
  #3   IP: 63.164.202.130
Old February 2nd, 2007, 11:53 AM
sloooo sloooo is offline
Senior Member with Distinction
 
Join Date: Oct 2006
Location: Redlands, California
Posts: 789
Default

Another way to check it is to turn your dryer on high and take an amp reading on one leg, and then on the other. They should be close to the same amperage. Compair this to the nameplate rating on the dryer. If your dryer nameplate says 30 amps and your draing 14, you know you have an issue with an element.
Reply With Quote
  #4   IP: 69.131.226.47
Old February 2nd, 2007, 05:58 PM
epojr epojr is offline
Junior Member
 
Join Date: Jan 2007
Posts: 25
Default

Thanks to both you guys. I really appreciate your well explained instructions, however I'm not too sure that I want to do any testing on hot 240V terminals and wires. I was severely shocked by 120 volts once, and I don't even want to think about getting zapped by 240.

I"ll check the exhaust ductwork for a blockage, and if the duct isn't blocked I think I'll take the dryer into an appliance store here in town and let their man check it out. I'm willing to try the DIY route on a lot of things, but I'm little skittish when it comes to messing around with hot 220V wires.
Reply With Quote
Reply






Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 08:11 AM.


Powered by vBulletin® Version 3.6.7
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
© 2002 - QuinStreet, Inc.
http://www.selfhelpforums.com