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Forum Index => Dryer Repair => Topic started by: GrantFair on October 08, 2010, 12:23:13 AM

Title: Hotpoint Dryer - no heat
Post by: GrantFair 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

Model DE750ET4191
Title: Re: Hotpoint Dryer - no heat
Post by: schaffersapplian 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.
Title: Re: Hotpoint Dryer - no heat
Post by: GrantFair 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
Title: Re: Hotpoint Dryer - no heat
Post by: JWWebster 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.
Title: Re: Hotpoint Dryer - no heat
Post by: GrantFair 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
Title: Re: Hotpoint Dryer - no heat
Post by: GrantFair 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
Title: Re: Hotpoint Dryer - no heat
Post by: JWWebster 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.
Title: Re: Hotpoint Dryer - no heat
Post by: GrantFair 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 
Title: Re: Hotpoint Dryer - no heat
Post by: whirlpooltech 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.
Title: Re: Hotpoint Dryer - no heat
Post by: jumptrout51 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.
Title: Re: Hotpoint Dryer - no heat
Post by: GrantFair on October 12, 2010, 06:44:25 AM
As far as I can tell the numbers are:

64T11208115
16183334-P001
L240F C8723

Grant
Title: Re: Hotpoint Dryer - no heat
Post by: GrantFair 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? 

Title: Re: Hotpoint Dryer - no heat
Post by: jumptrout51 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.
Title: Re: Hotpoint Dryer - no heat
Post by: GrantFair 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?
Title: Re: Hotpoint Dryer - no heat
Post by: JWWebster on October 12, 2010, 08:04:41 AM
Post a photo of your dryer motor switch
Title: Re: Hotpoint Dryer - no heat
Post by: GrantFair on October 13, 2010, 08:52:32 AM
Here goes:
Title: Re: Hotpoint Dryer - no heat
Post by: GrantFair on October 13, 2010, 09:23:57 AM
View from above:
Title: Re: Hotpoint Dryer - no heat
Post by: GrantFair 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?
Title: Re: Hotpoint Dryer - no heat
Post by: JWWebster 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.
Title: Re: Hotpoint Dryer - no heat
Post by: GrantFair 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?
Title: Re: Hotpoint Dryer - no heat
Post by: JWWebster on October 13, 2010, 10:21:37 AM
You can remove those 2 screws on the switch and easily see the tab. You can also take a peek inside at them leaf switches. Be careful, they will fall out easily. Sometimes the points will stick together as a result of arcing and time. Use a fingernail file and smooth up the surface of the points after unsticking them and put it all back together.
Title: Re: Hotpoint Dryer - no heat
Post by: GrantFair on October 13, 2010, 10:56:41 AM
Thanks, I will have a go at it tonite or tomorrow. It looks like that will require taking the motor out.
Title: Re: Hotpoint Dryer - no heat
Post by: JWWebster on October 13, 2010, 09:38:27 PM
Let me know
Title: Re: Hotpoint Dryer - no heat
Post by: GrantFair on October 14, 2010, 02:24:17 AM
Will do.

Any advice on detaching the motor shaft from the blower fan?

 
Title: Re: Hotpoint Dryer - no heat
Post by: JWWebster on October 14, 2010, 08:49:04 AM
That's not difficult on those. You simply remove a screw and she slides right off.
Title: Re: Hotpoint Dryer - no heat
Post by: GrantFair on October 18, 2010, 07:37:36 PM
I was able to fix the switch. Your diagnosis was correct, the leafs for the motor fail switch were stuck together and the contacts badly deformed. I was able to file them flat easily. (There's not much contact left, though). When I moved the spring device on the motor shaft back and forth by hand, they opened and closed according to the ohmmeter.

But  -  the machine screw (which holds a retaining metal device on the blower fan and shaft) had some kind of retaining nut which fell off when I removed the screw. It made a noise when it landed. I have been unable to get it out with a magnet. Tilting and shaking the dryer does not budge it (there is a lint coating in there on the fan and the blower body in spite of vacuuming).

So my next step is to remove the blower body. How hard is it to get it back in place and aligned properly with the motor shaft? Any advice on this step?
Title: Re: Hotpoint Dryer - no heat
Post by: JWWebster on October 18, 2010, 11:15:05 PM
Go ahead and remove that motor and blower housing and break it all down. Give the housing a good washout. Don't get the motor wet though.
Title: Re: Hotpoint Dryer - no heat
Post by: GrantFair on October 23, 2010, 11:21:35 PM
I removed the blower housing from the dryer, and washed out the lint, dried it off, and replaced it. I was also able to re-assemble the blower housing and put the fan back on the shaft.

However, the blower fan was hitting something at one location as it rotated. I adjusted the motor position slightly until the knock disappeared. But when I reinstalled the drum and belt, the noise returned. I removed the drum, tried more adjusting until the fan rotated quietly, put the the drum back, but the noise  was still there.

Couple of questions-

1) how much shaft should protrude beyond the fan retainer? Right now, it is about 1/8".

2) how much of the black plastic coupling ring on the fan side of the motor should fit into the retaining ring next to the blower? There is a shoulder on that black coupling ring, but it is nowhere snugged up to that retaining ring/clamp. There  is roughly 3/16" between the clamp ring and the shoulder.

Any other suggestions appreciated.
Title: Re: Hotpoint Dryer - no heat
Post by: JWWebster on October 24, 2010, 12:02:36 PM
Seems to me like their could have been some nylon washers between the fan blade and haft but I ain't sure. GE dryers hardly ever have blower problems like this.
Title: Re: Hotpoint Dryer - no heat
Post by: GrantFair on October 24, 2010, 05:29:17 PM
I didn't see any nylon washers.

I remember thinking a spacer between the fan and housing would have been helpful.

The noise was not a problem before I removed the motor and fan. I think I just put it back misaligned, and need to find how to realign it.

Anyone else have answers to my questions/
Title: Re: Hotpoint Dryer - no heat
Post by: JWWebster on October 24, 2010, 08:30:25 PM
Check your rubber mounts on each side of the motor.
Title: Re: Hotpoint Dryer - no heat
Post by: GrantFair on October 26, 2010, 02:55:28 AM
What should I be looking for?
Title: Re: Hotpoint Dryer - no heat
Post by: JWWebster on October 26, 2010, 08:24:29 AM
I got to thinking about it last night maybe some screws are backed out of the motor mount?