fixing my dishwasher

[rabbit killer]

My dishwasher stopped heating the water so I checked the heating element
resistance and I get 13 ohms.

Well the manual asks that it be plugged in to at least a 15 Amp circuit
and at 120 Volts I get R = V / I or 120/15 = 8 ohms just to get a
ballpark of what it should be.

However, some website says that heating elements should be in the
kilo-ohm range, so what is the error in my above thinking?

 

[John O'Flaherty]

On Mon, 20 Sep 2010 13:28:19 -0700, rabbit killer
<siccusproprius@gmx.com> wrote:

My dishwasher stopped heating the water so I checked the heating element
resistance and I get 13 ohms.

Well the manual asks that it be plugged in to at least a 15 Amp circuit
and at 120 Volts I get R = V / I or 120/15 = 8 ohms just to get a
ballpark of what it should be.

However, some website says that heating elements should be in the
kilo-ohm range, so what is the error in my above thinking?

First, there are different kinds of heating elements, but kilohms is
not for a water heater element. The appliance will draw less than 15
amps, because there is a motor load and the circuit has to be
over-rated for safety. Thirteen ohms cold sounds reasonable. It will
increase some as it heats up, but at startup you'd have 120 V /13 ohms
= 9.23 amps, or (120^2/13) = 1100 watts, which is reasonable. The
problem must be somewhere else - there may be a series thermal breaker
that has gone open-circuit, or the controller may not be turning the
heater on, or there may be a problem in the wiring.
Also, the dishwasher may have a setting to prevent heating the water,
relying on the hot water supply to do the job. You might check that.

--
John

 

[rabbit killer]

I will check the series thermal breaker. I tested my toaster and it's 14
ohms, so I think the dishwasher element is fine.

 

[Tom Biasi]

"rabbit killer" <siccusproprius@gmx.com> wrote in message
news:i78j7c$gve$1@news.albasani.net...

I tested my toaster and it's 14 ohms, so I think the dishwasher element
is fine.

Do you heat water with your toaster?

 

[Rich Grise]

On Mon, 20 Sep 2010 21:14:48 -0400, Tom Biasi wrote:

"rabbit killer" <siccusproprius@gmx.com> wrote in message
news:i78j7c$gve$1@news.albasani.net...
I tested my toaster and it's 14 ohms, so I think the dishwasher element
is fine.

Do you heat water with your toaster?

Well, some of the water in the bread evaporates as it toasts, but
was that really the point? A heating element of 13 or 14 ohms
resistance is probably not defective, was the point.

Hope This Helps!
Rich

 

[rabbit killer]

Tom Biasi wrote On 09/20/2010 06:14 PM:

"rabbit killer" <siccusproprius@gmx.com> wrote in message
news:i78j7c$gve$1@news.albasani.net...
I tested my toaster and it's 14 ohms, so I think the dishwasher
element is fine.

Do you heat water with your toaster?

That's silly. I'm just trying to get an order-of-magnitude idea of what
is a good number. This is a counter-top dishwasher and I suspect it uses
about the same amount of power as the toaster. I was also trying to
falsify the claim from the one website that said my heating element
should be in the kilo-ohm range.

So now, I have the uh... "thermal breaker"? that was wired in series and
is open. I'm guessing it should be closed until it reaches 90 C ("90 C
BYDQ" is imprinted upon it).

My question now is: what do I google to find this part? "thermal
breaker" is not working and I was wondering if there's a better name for it.

 

[rabbit killer]

John O'Flaherty wrote On 09/20/2010 01:44 PM:

On Mon, 20 Sep 2010 13:28:19 -0700, rabbit killer
rst, there are different kinds of heating elements, but kilohms is
not for a water heater element. The appliance will draw less than 15
amps, because there is a motor load and the circuit has to be
over-rated for safety. Thirteen ohms cold sounds reasonable. It will
increase some as it heats up, but at startup you'd have 120 V /13 ohms
= 9.23 amps, or (120^2/13) = 1100 watts, which is reasonable.

The

problem must be somewhere else - there may be a series thermal breaker
that has gone open-circuit, or the controller may not be turning the
heater on, or there may be a problem in the wiring.

the "series thermal breaker" is, in fact, open circuit and I am looking
to replace this part. However, when I google this I get a bunch of
"thermal circuit breakers" which list their ratings in Amps, not degrees
celsius. The only temp related one I could find was a "one shot thermal
cutoff" which just melts at a certain temperature and is done.

Imprinted on this switch is "90 C BYDQ" Does BYDQ mean "By flow of heat"?

I'm looking for ideas of other words to google...

Also, the dishwasher may have a setting to prevent heating the water,
relying on the hot water supply to do the job. You might check that.

It takes in cold water, per instructions, and worked fine for many
months before suddenly ceasing to work.

 

[Michael A. Terrell]

rabbit killer wrote:

John O'Flaherty wrote On 09/20/2010 01:44 PM:
On Mon, 20 Sep 2010 13:28:19 -0700, rabbit killer
rst, there are different kinds of heating elements, but kilohms is
not for a water heater element. The appliance will draw less than 15
amps, because there is a motor load and the circuit has to be
over-rated for safety. Thirteen ohms cold sounds reasonable. It will
increase some as it heats up, but at startup you'd have 120 V /13 ohms
= 9.23 amps, or (120^2/13) = 1100 watts, which is reasonable.

The
problem must be somewhere else - there may be a series thermal breaker
that has gone open-circuit, or the controller may not be turning the
heater on, or there may be a problem in the wiring.

the "series thermal breaker" is, in fact, open circuit and I am looking
to replace this part. However, when I google this I get a bunch of
"thermal circuit breakers" which list their ratings in Amps, not degrees
celsius. The only temp related one I could find was a "one shot thermal
cutoff" which just melts at a certain temperature and is done.

Imprinted on this switch is "90 C BYDQ" Does BYDQ mean "By flow of heat"?

Contact a local appliance repair place with the brand and model,
along with the markings on the part.

--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

 

[Tom Biasi]

"Rich Grise" <richgrise@example.net> wrote in message
newsan.2010.09.21.15.59.45.350110@example.net...

On Mon, 20 Sep 2010 21:14:48 -0400, Tom Biasi wrote:
"rabbit killer" <siccusproprius@gmx.com> wrote in message
news:i78j7c$gve$1@news.albasani.net...
I tested my toaster and it's 14 ohms, so I think the dishwasher element
is fine.

Do you heat water with your toaster?

Well, some of the water in the bread evaporates as it toasts, but
was that really the point? A heating element of 13 or 14 ohms
resistance is probably not defective, was the point.

Hope This Helps!
Rich

Yes Rich,

But my point was to caution against thinking that all heating elements are
the same.
That's all, a gentle nudge.
Tom

 

[Baron]

rabbit killer Inscribed thus:

Tom Biasi wrote On 09/20/2010 06:14 PM:


"rabbit killer" <siccusproprius@gmx.com> wrote in message
news:i78j7c$gve$1@news.albasani.net...
I tested my toaster and it's 14 ohms, so I think the dishwasher
element is fine.

Do you heat water with your toaster?



That's silly. I'm just trying to get an order-of-magnitude idea of
what is a good number. This is a counter-top dishwasher and I suspect
it uses about the same amount of power as the toaster. I was also
trying to falsify the claim from the one website that said my heating
element should be in the kilo-ohm range.

So now, I have the uh... "thermal breaker"? that was wired in series
and is open. I'm guessing it should be closed until it reaches 90 C
("90 C BYDQ" is imprinted upon it).

My question now is: what do I google to find this part? "thermal
breaker" is not working and I was wondering if there's a better name
for it.

Before you start on the thermal breaker, disconnect the heater and
measure the resistance to the case, only to make sure that the thermal
breaker hasn't opened because of a ground fault. The heater could have
a hole in the sheath. You should expect a reading of several megohms.
A megger is a better instrument for testing this than a multimeter.

12 to 14 ohms is about right for a heating element. The device that you
call "Thermal Breaker" is probably a protection device to prevent
overheating and/or "Boil Dry" conditions. If so there will probably be
a thermostat fastened to the tub to set the water temperature, either
directly or via a timer.


--
Best Regards:
Baron.

 

[1jam]

Tom Biasi wrote:

"Rich Grise" <richgrise@example.net> wrote in message
newsan.2010.09.21.15.59.45.350110@example.net...
On Mon, 20 Sep 2010 21:14:48 -0400, Tom Biasi wrote:
"rabbit killer" <siccusproprius@gmx.com> wrote in message
news:i78j7c$gve$1@news.albasani.net...
I tested my toaster and it's 14 ohms, so I think the dishwasher
element is fine.

Do you heat water with your toaster?

Well, some of the water in the bread evaporates as it toasts, but
was that really the point? A heating element of 13 or 14 ohms
resistance is probably not defective, was the point.

Hope This Helps!
Rich

Yes Rich,
But my point was to caution against thinking that all heating elements are
the same.
That's all, a gentle nudge.
T

Well I thought it was funny..

 

[John Fields]

On Tue, 21 Sep 2010 12:01:19 -0700, rabbit killer
<siccusproprius@gmx.com> wrote:

Tom Biasi wrote On 09/20/2010 06:14 PM:


"rabbit killer" <siccusproprius@gmx.com> wrote in message
news:i78j7c$gve$1@news.albasani.net...
I tested my toaster and it's 14 ohms, so I think the dishwasher
element is fine.

Do you heat water with your toaster?



That's silly. I'm just trying to get an order-of-magnitude idea of what
is a good number. This is a counter-top dishwasher and I suspect it uses
about the same amount of power as the toaster. I was also trying to
falsify the claim from the one website that said my heating element
should be in the kilo-ohm range.

So now, I have the uh... "thermal breaker"? that was wired in series and
is open. I'm guessing it should be closed until it reaches 90 C ("90 C
BYDQ" is imprinted upon it).

My question now is: what do I google to find this part? "thermal
breaker" is not working and I was wondering if there's a better name for it.

---
I suspect that what you have is a "thermal fuse", which is a fusible
link which opens (and stays that way) when its temperature rating is
exceeded.

If your heating element measures 13 ohms and you've got 120V mains,
then the current the heater will draw will be 120V/13R = 9.2 amperes.

With that in mind, since what you have is labelled 90C, what you
probably need is a 10 ampere 90C thermal fuse, like you can get here:

http://www.goodmans.net/get_item_th-tf93c_thermal-fuse-93-degrees-celsius.htm

---
JF

 

[rabbit killer]

John Fields wrote On 09/21/2010 12:53 PM:

On Tue, 21 Sep 2010 12:01:19 -0700, rabbit killer
siccusproprius@gmx.com> wrote:

Tom Biasi wrote On 09/20/2010 06:14 PM:


"rabbit killer"<siccusproprius@gmx.com> wrote in message
news:i78j7c$gve$1@news.albasani.net...
I tested my toaster and it's 14 ohms, so I think the dishwasher
element is fine.

Do you heat water with your toaster?



That's silly. I'm just trying to get an order-of-magnitude idea of what
is a good number. This is a counter-top dishwasher and I suspect it uses
about the same amount of power as the toaster. I was also trying to
falsify the claim from the one website that said my heating element
should be in the kilo-ohm range.

So now, I have the uh... "thermal breaker"? that was wired in series and
is open. I'm guessing it should be closed until it reaches 90 C ("90 C
BYDQ" is imprinted upon it).

My question now is: what do I google to find this part? "thermal
breaker" is not working and I was wondering if there's a better name for it.

---
I suspect that what you have is a "thermal fuse", which is a fusible
link which opens (and stays that way) when its temperature rating is
exceeded.

I found it! It's in the allied electronics catalog. It's a normally
closed (open on rise) THERMOSTAT that will open at 190 F and close again
at 172 F. There are many temperature choices... This thing is mounted
very close to the heating element.

http://www.goodmans.net/get_item_th-tf93c_thermal-fuse-93-degrees-celsius.htm

---
JF

No I'm pretty sure this is circuit is made to break every time the
dishwasher runs when the water is through heating.

 

[George Herold]

On Sep 21, 4:12 pm, rabbit killer <siccuspropr...@gmx.com> wrote:

John Fields wrote On 09/21/2010 12:53 PM:





On Tue, 21 Sep 2010 12:01:19 -0700, rabbit killer
siccuspropr...@gmx.com>  wrote:

Tom Biasi wrote On 09/20/2010 06:14 PM:

"rabbit killer"<siccuspropr...@gmx.com>  wrote in message
news:i78j7c$gve$1@news.albasani.net...
I tested my toaster and it's 14 ohms, so I think the dishwasher
element is fine.

Do you heat water with your toaster?

That's silly. I'm just trying to get an order-of-magnitude idea of what
is a good number. This is a counter-top dishwasher and I suspect it uses
about the same amount of power as the toaster. I was also trying to
falsify the claim from the one website that said my heating element
should be in the kilo-ohm range.

So now, I have the uh... "thermal breaker"? that was wired in series and
is open. I'm guessing it should be closed until it reaches 90 C ("90 C
BYDQ" is imprinted upon it).

My question now is: what do I google to find this part? "thermal
breaker" is not working and I was wondering if there's a better name for it.

---
I suspect that what you have is a "thermal fuse", which is a fusible
link which opens (and stays that way) when its temperature rating is
exceeded.

I found it! It's in the allied electronics catalog. It's a normally
closed (open on rise) THERMOSTAT that will open at 190 F and close again
at 172 F. There are many temperature choices... This thing is mounted
very close to the heating element.



http://www.goodmans.net/get_item_th-tf93c_thermal-fuse-93-degrees-cel...

---
JF

No I'm pretty sure this is circuit is made to break every time the
dishwasher runs when the water is through heating.- Hide quoted text -

- Show quoted text -

That's a one time fuse. It opens once. Sounds like there is some
other problem in your washer. The heater stayed on too long... the
fuse blew. Replacing the fuse will most likely cause it to fail again
when you use the dishwahser.
A local repair guy might be your best bet. (as someone suggested)
They may know what typically fails in your brand of dishwasher.

George H.

 

[John Fields]

On Tue, 21 Sep 2010 13:12:03 -0700, rabbit killer
<siccusproprius@gmx.com> wrote:

John Fields wrote On 09/21/2010 12:53 PM:

---
I suspect that what you have is a "thermal fuse", which is a fusible
link which opens (and stays that way) when its temperature rating is
exceeded.


I found it! It's in the allied electronics catalog. It's a normally
closed (open on rise) THERMOSTAT that will open at 190 F and close again
at 172 F. There are many temperature choices... This thing is mounted
very close to the heating element.

---
Good find!

Got a link to pin-point it?

---
JF

 

[rabbit killer]

I found it! It's in the allied electronics catalog. It's a normally
closed (open on rise) THERMOSTAT that will open at 190 F and close again
at 172 F. There are many temperature choices... This thing is mounted
very close to the heating element.



http://www.goodmans.net/get_item_th-tf93c_thermal-fuse-93-degrees-cel...

---
JF

No I'm pretty sure this is circuit is made to break every time the
dishwasher runs when the water is through heating.- Hide quoted text -

- Show quoted text -

That's a one time fuse. It opens once. Sounds like there is some
other problem in your washer. The heater stayed on too long... the
fuse blew. Replacing the fuse will most likely cause it to fail again
when you use the dishwahser.
A local repair guy might be your best bet. (as someone suggested)
They may know what typically fails in your brand of dishwasher.

George H.

here is the link. it looks exactly like this - i have a pair of calipers
and all the dimensions are the same. you have me second guessing myself
because i think you are more knowledgeable but i'm pretty sure this is
right. the one-time fuses look entirely different.


http://www.alliedelec.com/search/searchresults.aspx?N=0&Ntk=Primary&Ntt=557-0013

 

[rabbit killer]

George Herold wrote On 09/21/2010 01:51 PM:

That's a one time fuse. It opens once. Sounds like there is some
other problem in your washer. The heater stayed on too long... the
fuse blew. Replacing the fuse will most likely cause it to fail again
when you use the dishwahser.
A local repair guy might be your best bet. (as someone suggested)
They may know what typically fails in your brand of dishwasher.

George H.

okay, i just pulled something else out - there is what looks to me like
a thermocouple but i will describe it: it is in a sheath .2 inches
diameter and 1 inch long. it was located between the coil of the heating
element. on the outside, there are two really thin-gauge leads going to
the computer. eletrically, this component tests 'open' with my multimeter.

the thermostat was hooked up on the thick-gauge power in series with the
heating element.

so is the thermostat back-up and the thermocouple tells the computer
when to turn the heat off? or is it, like george suggests, a thermal
fuse that just blew telling the computer to turn off the power?

either way, the thermostat is open which means it needs to be replaced.
i will try again to get the manufacturer on the phone.

rK

 

[ehsjr]

rabbit killer wrote:

John O'Flaherty wrote On 09/20/2010 01:44 PM:

On Mon, 20 Sep 2010 13:28:19 -0700, rabbit killer

rst, there are different kinds of heating elements, but kilohms is

not for a water heater element. The appliance will draw less than 15
amps, because there is a motor load and the circuit has to be
over-rated for safety. Thirteen ohms cold sounds reasonable. It will
increase some as it heats up, but at startup you'd have 120 V /13 ohms
= 9.23 amps, or (120^2/13) = 1100 watts, which is reasonable.



The

problem must be somewhere else - there may be a series thermal breaker
that has gone open-circuit, or the controller may not be turning the
heater on, or there may be a problem in the wiring.


the "series thermal breaker" is, in fact, open circuit and I am looking
to replace this part. However, when I google this I get a bunch of
"thermal circuit breakers" which list their ratings in Amps, not degrees
celsius. The only temp related one I could find was a "one shot thermal
cutoff" which just melts at a certain temperature and is done.

Imprinted on this switch is "90 C BYDQ" Does BYDQ mean "By flow of heat"?

I'm looking for ideas of other words to google...

I've had the same problem (a bad thermal cutout) - searched
through Mouser, Newark, Digikey etc catalogs online - no joy.
Then, I got hold of the appliance manufacturer's parts list.
Bingo! They might call the part by some wierd name, but
you can tell by the pictorial diagrams that it *is* the part
you need.

Following Mike Terrell's post makes it even simpler!

Ed

 

[baron]

rabbit killer Inscribed thus:

I found it! It's in the allied electronics catalog. It's a normally
closed (open on rise) THERMOSTAT that will open at 190 F and close
again at 172 F. There are many temperature choices... This thing is
mounted very close to the heating element.




http://www.goodmans.net/get_item_th-tf93c_thermal-fuse-93-degrees-cel...

---
JF

No I'm pretty sure this is circuit is made to break every time the
dishwasher runs when the water is through heating.- Hide quoted text
-

- Show quoted text -

That's a one time fuse. It opens once. Sounds like there is some
other problem in your washer. The heater stayed on too long... the
fuse blew. Replacing the fuse will most likely cause it to fail
again when you use the dishwahser.
A local repair guy might be your best bet. (as someone suggested)
They may know what typically fails in your brand of dishwasher.

George H.


here is the link. it looks exactly like this - i have a pair of
calipers and all the dimensions are the same. you have me second
guessing myself because i think you are more knowledgeable but i'm
pretty sure this is right. the one-time fuses look entirely different.

Actually not ! The device on you're dishwasher could be either. I have
several physically identical devices to the one in your link, some
are "non re-entrant" that is "not re-settable" thermal fuses.

I note that from another post that you have found another thermal
sensor ! From the description you have given either device may be the
one that is used for temperature regulation.

http://www.alliedelec.com/search/searchresults.aspx?N=0&Ntk=Primary&Ntt=557-0013

--
Best Regards:
Baron.

 

[John Fields]

On Tue, 21 Sep 2010 19:11:31 -0700, rabbit killer
<siccusproprius@gmx.com> wrote:

George Herold wrote On 09/21/2010 01:51 PM:


That's a one time fuse. It opens once. Sounds like there is some
other problem in your washer. The heater stayed on too long... the
fuse blew. Replacing the fuse will most likely cause it to fail again
when you use the dishwahser.
A local repair guy might be your best bet. (as someone suggested)
They may know what typically fails in your brand of dishwasher.

George H.

okay, i just pulled something else out - there is what looks to me like
a thermocouple but i will describe it: it is in a sheath .2 inches
diameter and 1 inch long. it was located between the coil of the heating
element. on the outside, there are two really thin-gauge leads going to
the computer. eletrically, this component tests 'open' with my multimeter.

the thermostat was hooked up on the thick-gauge power in series with the
heating element.

so is the thermostat back-up and the thermocouple tells the computer
when to turn the heat off? or is it, like george suggests, a thermal
fuse that just blew telling the computer to turn off the power?

either way, the thermostat is open which means it needs to be replaced.
i will try again to get the manufacturer on the phone.

---
I'm guessing that the cylindrical component is a Normally-Open close
on rise thermal switch, and the other component is a thermostat which
has failed open.

The reasoning behind that is that if the thermostat failed shorted and
there wasn't something else in there measuring the temperature, the
temperature could rise to destructive levels.

All just a guess, mind you.

You might get better results from sci.electronics.repair or, better
yet, the service manual if you can get one.

---
JF