34 replies to this topic

[Mr. Chris]

At the risk of sounding like a moron (which is not too far off in this particular field), I did replace the 10-hour timer with the 8-hour universal timer recommended.  As far as the thermometer goes, though...uh...I didn't find it.  I need Batman (TV show with Adam West, not the current manifestations) signage telling me everything.  Searching the Sears parts website didn't show a thermometer as a part.  Yeah, I know, it has to have one.  I did find something that may have been the thermo, but it was different.  It is above the coils in the freezer section - the top 3^rd of which was thickly frosted all the way across - with two wires connected to the wiring "cluster" and a ground from the cluster, to the fan motor (the replacement has no area for a ground, btw). 

The timer was quite different, too.  I found the timer (even with a Batman sign) and it is darn near twice the size of the new one.  I understand there have been at least a couple innovations and technological advances from when this was made to now that could concievably resulted in a vastly smaller timer.  My main concern is the lack of a grounding "prong" for the wire to clip on like the original.  Is this a problem?

After you clean up the beer you just blew out your nose when you read of my incompetence, would you counsel me in this?

Chris

p.s.  What is the 'dial' on the bottom of the timer for?  Is it a manual on/off that you need to actuate initially?  I was disheartened when I plugged the fridge back in, turned it on and got nothing in return.  Once I turned the timer 'dial' one click, the fridge came on.

 

[FatMan]

Hi C,  The part you found above the coils is the defrost thermostat, if you jump the two wires together going to this part the heater should come on, don't worry about the ground wire it's grounded when you clip it on to the evaporator  The dial on the timer is there to so you can manually advance the timer(no problem with you doing that)advance the timer until you hear the first click this will put it in the defrost cycle  You mentioned mold on the gasket, sure sign of air leak. Check the refrigerator door gasket on the bottom, can almost quarantee it's torn. You didn't mention if you pulled the unit out and checked the condensor fan motor and if condensor coil was clean, and how hot is that compressor? 

                                            Good Luck, FatMan                                          

 Ken's Appliance Service                                                                                             

Rootstown, Ohio                                                                                                

                                                                                                                                                                                                           

[Mr. Chris]

Fatman,

Pulled fridge out in January to clean the coils and was quite disgusted with my findings.  Earlier this month, I vacuumed the coils again.  With a dog and an old fridge, I think I'm going to try to keep the "every 3 months" schedule going. 

All fans are working, at least as far as I can tell.  When you ask 'how hot?,' are you looking for an actual degree or just a "by feel" reading?  I suppose resting my digital probe on the compressor would give me some reading, but I don't know how accurate. 

I'm curious to see what the fridge temperatures are this evening since that gives the timer almost 20 hours to stabilize things.  I will go at the thermometer either tonight (depending on my disposition...was up very late last night) or my day off tomorrow. 

There is one tear in the fresh food gasket.  Bottom corner.  The worst area, visually, is the top section of the fresh food door.  Methinks that has more to do with lack of cleaning than a tear.  This fridge doesn't have to last more than a couple years.  I will be inheriting my parent's SxS when they remodel their kitchen and that could be any time now so I really don't want to drop another $55 for a gasket if I don't need to.  If we decide to keep this fridge and get rid of the one in the basement, I don't think I'll question the gasket purchase.  I will be purchasing a refrigerator thermometer (to keep in the freezer or the fresh food area) tomorrow so I can keep track of temperature.

Thanks for all the help.

Chris

[FatMan]

Hello again C,

        Repace the defrost thermostat and see if you can heat up that door gasket to try and straighten it out, if your going to fix it let's do it right and replace those gaskets. Remember you can get those parts here. As far as the temperature of the compressor goes, as long as you can put your hand on it and not get burnt:yikes:

[Mr. Chris]

Well, the thermostat is replaced.  I also bought a fridge/freezer thermometer.  About 3 hours ago, the freezer registered 25°F and the fridge registered 42°F 15 minutes later.  I set the fridge to cool more with its own dial and the temperature at this moment is 39°F.  I am happy with those readings.  I am going to have to check the freezer temperature again, but I am making sure the thermometer is reading right (let it come to room temp and rate it against a digital thermometer). 

I want to make sure I have this correct, too.  My fridge has two controls, one for the freezer and one for the fridge.  The fridge dial has an electronic part connected to it and the freezer dial has a connection to a baffle that changes the amount of cold air from the freezer that comes into the fridge.  Is that right or does my refrigerator have it's own set of coils for cooling? 

I can see it would be easier to make the freezer cold with the baffle not allowing as much cold air into the fridge (which is what happens when you turn the dial towards "colder").  Is it correct that the compressor is controlled by the fridge control dial?  That is, does the fridge run more/more often (everything else being equal) with the fridge dial turned towards "colder?"

Chris

 

[Samurai Appliance Repair Man]

Nice work getting the parts installed.

More information on setting refrigerator controls here.

[The Seven]

[user=238]cdelsig[/user] wrote:

  Is that right or does my refrigerator have it's own set of coils for cooling? 

No. Only one evaporator coil in the freezer compartment

Is it correct that the compressor is controlled by the fridge control dial?  

Yes.

That is, does the fridge run more/more often (everything else being equal) with the fridge dial turned towards "colder?"

Yes.

[Mr. Chris]

Well, now I have quite a bit more insight in the workings of a refrigerator.  Thanks, everyone, for all the help. 

One last question (at least for now)...at what friggin' temperature does ice cream freeze?!?  The freezer is currently around 21° and the ice cream is still soup.  I wonder if this current tub is long past freezing again.  I'll have to check the freezer in the basement. 

Chris

 

[Samurai Appliance Repair Man]

This is a good heat transfer problem, worked many like this in Heat Transfer class in undergrad. The temp of the freezer doesn't tell you the temp of the icecream. It will take some determinate period of time for the icecream to pull down. That time is calculated by:

q=k*A*Delta(T) where:

q= the rate of heat transfer in joules/sec or BTUH

k= the appropriate heat transfer coefficient

A= the surface area of the object being chilled

Delta(T)= the change in time from state 1 to state 2, in seconds

This is simplistic, of course, because it allows only for conductive cooling. In a freezer, convective cooling would be a significant factor and would further reduce the pull down time.

Go ahead and make a first-brush calculation, state all assumptions, and I'll check your work.

P.S., as anyone who's made homemade icecream knows, you have to get the icecream slurry to 27F or below before it begins to harden.

[Mr. Chris]

Okay, so...

 ΔT = q / (k * A)

Since there is an insulation factor of the carton and that is completely surrounding the ice cream (unless we would open the container, but that would really seriously skin over the ice cream and that may be worse than eating ice cream mousse), A would have to be the entire surface area, not just the top of the ice cream.

Further, wouldn't q be directly related to the difference in temperature (as the temperature differential increased, rate of cooling increases and vice versa)? So to figure this out as accurately as possible, with a changing variable, wouldn't we have to integrate somewhere in there?

Where would one find k?  Does it have to do with the specific gravity of the item changing temperature?

Chris

 

[Samurai Appliance Repair Man]

[user=238]cdelsig[/user] wrote:

Where would one find k?  Does it have to do with the specific gravity of the item changing temperature?

 

Nothing to do with the body being cooled, it's dependant upon the conditions at the surface, the "film" layer.  K is often determined experimentally but there are published tables available.  A brief overview of the concept is presented here.

[Mr. Chris]

Well, this particular part of the thread has gone a bit past my education in thermodynamics.  Well, if you define "a bit" to mean at least a parsec.  I haven't had much thermodynamics past high school.  Calc, yes, but not thermodynamics. 

My freezer in the basement (which is a Hotpoint that is probably at least as old as my Whirlpool) has solid ice cream and is a frosty 9°F.

So, the freezer compartment needs to be somewhere between 9°F and 21°F to cause ice cream to be hard.  If I were to dial my fridge to 'as cold as possible' and close the baffle between the freezer and the fridge as far as it goes, what would be the lowest possible degree at which you would say, "the fridge is not working as it should and needs to have the refrigerant recharged or the unit needs to be scrapped?"

Chris

p.s.  There seems to be quite a bit of integration in that equation.  'K' is defined by a changing variable and, thus, the original has at least 2.

[Samurai Appliance Repair Man]

[user=238]cdelsig[/user] wrote:

So, the freezer compartment needs to be somewhere between 9°F and 21°F to cause ice cream to be hard. 

You should be able to achieve 0F in your freezer-- this is the ideal temp. 

Freezer temp and icecream temp are two different things.  It takes time for the icecream (and everything else) to reach steady state.  That was the point of our excursion into heat transfer.

[Mr. Chris]

Freezer temp and icecream temp are two different things.  It takes time for the icecream (and everything else) to reach steady state.  That was the point of our excursion into heat transfer.

That was understood.  I am also happy to report that the 'mousse' is now much firmer than it was last night. :D  I'm still not sure at what temperature ice cream has to be to harden.  Geez, maybe I'll have to get a 3^rd multitester and make sure this one has temperature probes, or maybe I'll get one of those infrared "guns."  At least now I will be checking the temp of the ice cream and not the freezer temp. 

Chris

 

[Samurai Appliance Repair Man]

I already told you about the temp at which icecream hardens.  You musta missed it.  From my first post on heat transer:

[user=1]Samurai Appliance Repair Man[/user] wrote:

P.S., as anyone who's made homemade icecream knows, you have to get the icecream slurry to 27F or below before it begins to harden.