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Author Topic: Hotpoint Dryer - no heat  (Read 18175 times)

Offline GrantFair

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Hotpoint Dryer - no heat
« on: October 08, 2010, 12:23:13 AM »

I have a Hotpoint dryer bought in 1987. The drum rotates fine, but there is no heat.

I have checked for continuity in the heater coils, and thermostats. They are all fine. The door switch works.

I tried to check the 'run switch'. I'm unsure of the right connections, but I removed the two biggest wires (black) from the switch block on the motor, and checked for continuity between the two lugs after turning the motor on. I got continuity, for both motor running, and motor off. (I think it is supposed to be no continuity if the motor is not turning.)

How can I be sure I have the right connections to check this switch? (There is no schematic for the machine anywhere on it).

If I did have the right connections, does the continuity being on for both motor running and not running mean the switch needs replacement?

Grant

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Offline schaffersapplian

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Re: Hotpoint Dryer - no heat
« Reply #1 on: October 08, 2010, 05:54:55 AM »
Be sure that you have 240V at your dryer outlet.  If you only have 120v, that can cause it not to heat, but still run.
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Offline GrantFair

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Re: Hotpoint Dryer - no heat
« Reply #2 on: October 08, 2010, 07:25:45 AM »
I was sure the circuit breakers were fine. But when I checked, one leg was at 0v.Then I found the breaker which had tripped. I reset it and the heat was back. Thanks!

I spent a lot of time learning a lot about this dryer, but it was better than spending $120 for a technician to reset the breaker!

Thanks,

Grant

Offline JWWebster

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Re: Hotpoint Dryer - no heat
« Reply #3 on: October 08, 2010, 12:25:36 PM »
Them breakers get bad on the heat load side.I had one here at the shop that was giving me fits.
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Offline GrantFair

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Re: Hotpoint Dryer - no heat
« Reply #4 on: October 11, 2010, 11:14:05 PM »
I assume the breaker is ok because it only trips twice a year or so.

I had a new problem,  a grinding noise when the drum was turning. One of the glides and fallen out. That problem is fine, now that I replaced it snugly.

But - a new problem - did not have this problem before I took the machine apart - the heater does not go off if I stop the dryer in the middle of a cycle by opening the door.

Only thing I can think of is I might have reversed the two black wires to the motor run switch, could that cause the problem?

Thanks for your help to date,

Grant

Offline GrantFair

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Re: Hotpoint Dryer - no heat
« Reply #5 on: October 12, 2010, 12:11:56 AM »
The heater was working fine when I was writing the last post. Then I went down to check it and there was no heat!
 
I will not have time to check the coils until tomorrow night. I guess if they are overheating that might help them burn out? When I checked last week, the resistance of one element was 22.5 ohms; the other was about 30 ohms.

This dryer has what look like a total of three stats. Two thermostats are piggy backed on each other, attached to the heater drum (see picture below). They  both showed continuity last week. I assume these are the safety stats. The only number I could see on the top stat was L240.

The third stat is mounted under the lint filter in the dryer door. It too showed continuity last week. I guess this is the operating stat?

Grant

Offline JWWebster

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Re: Hotpoint Dryer - no heat
« Reply #6 on: October 12, 2010, 12:47:38 AM »
That one pictured is a limit. The control tstats will be under the filter housing. Mostly their is more than one. L240 is way too high a temp for clothes drying. A cotton stat is 160f max and permapress is 140ish.
« Last Edit: October 12, 2010, 12:50:27 AM by JWWebster »
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Offline GrantFair

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Re: Hotpoint Dryer - no heat
« Reply #7 on: October 12, 2010, 01:13:31 AM »
I have never seen a picture of anything in online parts pictures which looks like that piggy-back limit thermostat in my picture. (None of the online parts websites recognize my dryer model number).

I will have to ask at a local parts place. What wold you suggest as a replacement part? This thing has worked fine for 27 years; only had the glides replaced once and as far as I know the thermostat in the picture is original.

Any other advice about what might cause the heater coils to stay on when the drum is not moving? I tried to check continuity for the run switch, as noted in a previous post, but got continuity no matter what.

Grant 

Offline whirlpooltech

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Re: Hotpoint Dryer - no heat
« Reply #8 on: October 12, 2010, 02:07:30 AM »
Quote
I have never seen a picture of anything in online parts pictures which looks like that piggy-back limit thermostat in my picture. (None of the online parts websites recognize my dryer model number).

What does it say on the back of the part? I can see something in the photo but can make out any of the number.
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Offline jumptrout51

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Re: Hotpoint Dryer - no heat
« Reply #9 on: October 12, 2010, 06:41:35 AM »
The centrifugal switch on the motor is sticking in the closed position causing the heater to stay on in the off position.
It may also be responsible for the breaker tripping.

You already verified that with your motor switch continuity test.
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Offline GrantFair

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Re: Hotpoint Dryer - no heat
« Reply #10 on: October 12, 2010, 06:44:25 AM »
As far as I can tell the numbers are:

64T11208115
16183334-P001
L240F C8723

Grant

Offline GrantFair

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Re: Hotpoint Dryer - no heat
« Reply #11 on: October 12, 2010, 06:50:22 AM »
Is there any place that sells the centrifugal switch by itself? I understand as a rule you have to buy a new motor with centrifugal switch. And I suspect the motor is not being manufactured any more.

Or, is it possible to repair the centrifugal switch? 


Offline jumptrout51

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Re: Hotpoint Dryer - no heat
« Reply #12 on: October 12, 2010, 07:03:13 AM »
The centrifugal switch is on the motor shaft and is not a replaceable part.
You may be able to clean any lint and dust from around it then manually move it back and forth to free it up.
The motor is available.
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Offline GrantFair

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Re: Hotpoint Dryer - no heat
« Reply #13 on: October 12, 2010, 07:32:26 AM »
Is the brown plastic device with a number of lugs attached to the motor not related to the run switch? If I understand your post the run switch is internal to the motor?

Offline JWWebster

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Re: Hotpoint Dryer - no heat
« Reply #14 on: October 12, 2010, 08:04:41 AM »
Post a photo of your dryer motor switch
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Offline GrantFair

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Re: Hotpoint Dryer - no heat
« Reply #15 on: October 13, 2010, 08:52:32 AM »
Here goes:

Offline GrantFair

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Re: Hotpoint Dryer - no heat
« Reply #16 on: October 13, 2010, 09:23:57 AM »
View from above:

Offline GrantFair

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Re: Hotpoint Dryer - no heat
« Reply #17 on: October 13, 2010, 09:29:05 AM »
From reading, I understand that there are two centrifugal switches on dryer motors. One is for starting, and after the motor starts, it disconnects the start circuit. The other switch is a safety feature which ensures that if the motor is not turning, the heat is off.

Is this the way this motor works?

Offline JWWebster

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Re: Hotpoint Dryer - no heat
« Reply #18 on: October 13, 2010, 09:56:42 AM »
You gota couple of leaf switches inside the black box. The box itself has a metal tab sticking out that you can't see. When the motor takes off the springloaded flyweights get slung outwards and the tab gets released. The 2 leaf switches inside change contacts. One powers the heating element circuit so the motor must be running before the heater comes on. The other make the jump from start to light speed (run). In motors this age the fly weights will stick holding the heater element on till the timer is turned off. Lubricating the sliding flyweights on the shaft can sometimes fix the problem. I have one of those switches on a motor in my shop.
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About the icons: The beer is tip link, if a tech saves ya some money buy em a 6 pack. The small green square=personal message. The green dot is a link to my web page on appliance repair and other general BS I love to post. The letter sends me email.
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Offline GrantFair

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Re: Hotpoint Dryer - no heat
« Reply #19 on: October 13, 2010, 10:06:46 AM »
How do you get at them?

Also, can you see that metal tab you mention on the second picture of the motor (view from above), between the shaft and the switch case?