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Its that time of year again 🙁 Spent twenty minutes today trying to convince a customer that the freezer on her single stat/single compressor fridge freezer is defrosting because it is too cold in her garage. Does anyone have anything “offical” looking, from one of the major manufacturers perhaps, which can be used to back up an engineer when the customer is convinced he is lying to her 🙁 “I have never heard anything so ridiculous!” was repeated several times.
I have checked several customer manuals from different manufacturers and they all seem to put in a small note giving the operating range but do not explain why. 😕Re: Fridge Freezer Cold Location
some of the old Tricity, E/Lux books etc use to tell the customer of the room ambient temp range, for these types of models. can you get any copies.
TELL..Re: Fridge Freezer Cold Location
I had a call in the summer to a fr/freezer located in a conservatry the red warning light for the freezer was on, explained to cust it was the location as it was to warm , i told her to move into house just been back again red light on again due to cold weather and no heating in the place it was to cold,it was torture trying to explain, i think she thought i was pulling her leg.
Re: Fridge Freezer Cold Location
as Tell say’s it should be in customers care book Zanussi used put room ambient working temp in there manuals so it should be on Tds I will have a recce for you 😯
Re: Fridge Freezer Cold Location
First, may I apologise to anyone whom I’m teaching to suck eggs!
Most domestic appliances are design to operate in a “kitchen” enviroment, that translates to approx 20″ Centigrade ambient temp, with a little + or – lee way on that.
The condensor (the black metal grid) on the rear of the appliance is designed to match the FF system and dissapates heat generated in the gas by the act of compressing the gas, via the compressor. This dissapation is calculated and determines the overall surface area of the condensor, known quanties are the bore and stoke of the compressor, the PSI output, the length and bore of the pipe work and the volume of delivery tube and filter restriction, along with venturi design and evaporator expansion to create “boil off”. To have a good understanding of the effect please study Boyles Law.
The point is that this is a precise science, any alteration to a variable is detrimental to the objective.
Therefore to produce a refrigeration effect and remove heat requires a precise equation happening at the point its suppose to happen, the venturi within the evaporator. Alter the volume, temperature, pressure and it all goes “west”, Boyles Law.For instance R134a requires -28 degrees to be achieved to produce boil off and zero back pressure, r600a around -34 degrees and a back pressure of -0.06.
Complicated…….not really, but its important to appreciate that a condensor is designed to cool the appliance gas to a working temperature designed to the system. Therefore to hot or too cold causes problems.
Would anyone like a training issue at the forth coming meeting in February?Kevin
Re: Fridge Freezer Cold Location
Is this problem not related to whether or not there is a defrost heater behind the fridge compartment evaporator?
I was taught that the twin temp hotpoint appliances have a thermostat with a cut in temperature of +4 degrees C. If the ambient is too low, the fridge compartment never reaches +4C so that the compressor doesn’t cut back in. On an appliance with a defrost heater the problem does not exist…
Or have I got that wrong somewhere…
Bob
Re: Fridge Freezer Cold Location
Bob,
Imagine a garage at 0 degrees during the night and the FF kicking in on the stat, the extraction of heat from the compression effect on the gas within the condensor is detrimental and unrecoverable by any heater within the appliance. The delivery pressure to the venturi is screwed up from the ambient temperature, as most freezers take the gas pressure 1st with the fridge having second bite as well as the controlling stat its end of story.
Therefore what happens when the temperature is 90+ because its in a porch/conservatory? Google Boyles Law and have a read.
KevinRe: Fridge Freezer Cold Location
The ancient egyptians had access to a cold beer! No greenhouse issues, no gas to collect, no R134a or oil contamination.
How!
Easy, evaporation.
Take an earthenware pot, turn it upside down, in the full blast of the sun, and spray it with water. The evaporation effect of the suns heat on the surface of the pot evaporated the water and removed heat from the pot surface. This effect removed heat from the interior of the space created by the upturned pot. It became cold.
Don’t believe? Then think why when you get out of the shower or bath that you feel cold, its water evaporating off the surface of your skin removing your body heat at the same time. Simple.
Fancy a cold beer, ask the ancients.
Kevin
Re: Fridge Freezer Cold Location
I don’t do refrigeration so I suppose I look at these things from the customers perspective. In my previous house the kitchen was a single brick thickness extension with, for the first year or 2, no heating. It was cold and slightly damp, not ideal for a fridge freezer but my old Candy worked perfectly until a steel pipe rotted through. I bought a new Tricity Bendix FF and had problems straight away with condensation forming along the edges of both sides where they met the fridge door seal. I called Service Force? out to look at it and they said it was my kitchen that was to blame. I could have accepted this if I’d had similar problems with the old appliance but it had always stayed dry. It now lives in a centrally heated kitchen but the paintwork is starting to bubble up. The FF is 4 years old. 🙁
Re: Fridge Freezer Cold Location
Kevin
I am quite happy with the principal of a refrigeration system. What I was after is something in black and white from a recognised body which can be given to the customer. The vast majority of customers do not want to know the principal behind a system they just want to know why they have lost £150 of food in a one month old fridge freezer and the engineer is there saying it is her fault for putting it in a garage. It would just save a lot of time and often aggravation if the engineer could give a quick explanation and then say if you don’t believe me then there it is in black and white from the British Refrigeration Society (or some such body). The manufacturers seem to want to hide the fact that their appliances will not work in a cold location. (which can include a lot of kitchens on a cold winters night) To cut costs and produce cheaper appliances they have moved away from twin compressors and twin thermostat/valve units to ones which are controlled by a single stat in the fridge. Less than 14 degrees in the room and the unit does not cycle on often enough to keep the freezer temperature correct 😕 Of course it would save a lot of hassle if the shop staff would actually tell the customers this but a 1{e5d1b7155a01ef1f3b9c9968eaba33524ee81600d00d4be2b4d93ac2e58cec2d} chance of losing a sale. No they will just keep their mouth shut and worry about it later. 😡Terry, if you can come up with a model number I can get the manual printed off. 🙂
Bob , evap heaters and other variations (I think Bosch leave the fridge lamp half on to give the fridge an incorrect reading) make very little difference. They may work down to 10 degrees instead of 14.
Re: Fridge Freezer Cold Location
Flyman wrote:What I was after is something in black and white from a recognised body which can be given to the customer.
Sounds like something to be cooked up by one of our fridge wonks for the Downloads and Articles section. Make it look tidy etc, should do the trick. Any takers?
Chris.
Re: Fridge Freezer Cold Location
Hi Flyman,
Can’t help with an official declaration from manufacturers that their products are subject to the customer only using them in a suitable location.
Never happen that.
However if all engineers were to have a more in depth knowledge of the “whys and wherefores” perhaps we can at least educate ourselves and create the sort of enviroment where our advise was taken as a definative, not dis-believed.
Kevin
Re: Fridge Freezer Cold Location
Lots of engineers have the knowledge but don’t have the time for an in debt arguement with people that have no knowledge, I use to carry a print out to hand to them.
We also many years ago fitted a heater in some to overcome this which was the second best solution.
Kirk
Re: Fridge Freezer Cold Location
I seem to remember that this problem was highlighted through BBC’s watchdog program some five years ago. I wonder if we can resurrect some information that was around then as it is sure to raise it’s head this winter with the promises of sub zero temperatures.
Bob
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