Our 4 yr old Hotpoint frost-free freezer started playing up recently.
The 'Temp too high' light came on - and ice cream in the top drawer was
semi melted. Turned the temperature control down and the light went out
- but ice cream was still not as 'solid' as it should be.

Was on the point of calling out an engineer when I read an earlier post
on a similar problem. Someone pointed out that even though there is no
visible 'frost' inside the cabinet - the evaporator, hidden behind the
fan 'trunking', can become iced up and reduce the cooling efficiency.

So we did a 'de-frost' - and were surprised at the amount of water that
came out.

Turned the freezer back on - and it's working perfectly again. So thanks
to uk.d-i-y and contributors for saving me at the least a call-out charge!


--
Kev

Justice? You get justice in the next world,
in this world you have the law...
William Gaddis

On 31/10/2011 11:18, Ret. wrote:
Our 4 yr old Hotpoint frost-free freezer started playing up recently.
The 'Temp too high' light came on - and ice cream in the top drawer was
semi melted. Turned the temperature control down and the light went out
- but ice cream was still not as 'solid' as it should be.

Was on the point of calling out an engineer when I read an earlier post
on a similar problem. Someone pointed out that even though there is no
visible 'frost' inside the cabinet - the evaporator, hidden behind the
fan 'trunking', can become iced up and reduce the cooling efficiency.

So we did a 'de-frost' - and were surprised at the amount of water that
came out.

Turned the freezer back on - and it's working perfectly again. So thanks
to uk.d-i-y and contributors for saving me at the least a call-out charge!


Hmmm.. Having done a bit more Googling on the subject, it appears that
I may not be out of the woods yet - and if the evaporator is icing up,
then that could be a symptom of a failed sensor or defrost timer...

I'll just have to wait and see what happens.


--
Kev

Justice? You get justice in the next world,
in this world you have the law...
William Gaddis

On 31/10/2011 11:30, Ret. wrote:

Hmmm.. Having done a bit more Googling on the subject, it appears that I
may not be out of the woods yet - and if the evaporator is icing up,
then that could be a symptom of a failed sensor or defrost timer...

.... or the defrost heater itself - a common fault.

--
Andy

On Oct 31, 11:30*am, "Ret." wrote:

Hmmm.. *Having done a bit more Googling on the subject, it appears that
I may not be out of the woods yet - and if the evaporator is icing up,
then that could be a symptom of a failed sensor or defrost timer...

I had a similar problem with a frost-free freezer recently. The
refrigerant system seemed to be working, though not shifting the heat.
I got an 'engineer' through Domestic & General; he seemingly knew
nothing more than I did and levered the plastic trim off the back
(breaking it) before leaving without fixing it , saying he'd consult
a colleague and ring back.

He didn't ring back. Since it would be scrap if not fixed, I set
about it and after an hour of gentle prodding at the trim, got access
to the PCB and sensor connections through the front (NB there is no
access through the back). The two thermistors had very different
resistances. I repleaced one, with a manufacturers kit (£30! For a NTC
thermistor!!) and it went.

The internet recommendation seems to be to avoid frost free
appliances.

I've had dealings with many thermistors as sensors on BMS
installations, probably 1,000+ on one site, sensing from 4 to 100 degC
approximately. I do not recall that they went ever wrong, but they
seem to be a source of constant failures on domestic freezers and
fridges, which are then scrapped because the "Engineer" can't replace
them or his labour charges make the replacement of a £30 thermistor
uneconomic. If the thermistors fail so frequently, surely the
encapsulation must be defective? There's nothing else to go wrong,
SFAIK.

Or is this engineered-in failure to ensure a constant demand for
replacements?

On 31/10/2011 12:45, Onetap wrote:
On Oct 31, 11:30 am, wrote:

Hmmm.. Having done a bit more Googling on the subject, it appears that
I may not be out of the woods yet - and if the evaporator is icing up,
then that could be a symptom of a failed sensor or defrost timer...

I had a similar problem with a frost-free freezer recently. The
refrigerant system seemed to be working, though not shifting the heat.
I got an 'engineer' through Domestic& General; he seemingly knew
nothing more than I did and levered the plastic trim off the back
(breaking it) before leaving without fixing it , saying he'd consult
a colleague and ring back.

He didn't ring back. Since it would be scrap if not fixed, I set
about it and after an hour of gentle prodding at the trim, got access
to the PCB and sensor connections through the front (NB there is no
access through the back). The two thermistors had very different
resistances. I repleaced one, with a manufacturers kit (£30! For a NTC
thermistor!!) and it went.

The internet recommendation seems to be to avoid frost free
appliances.

I've had dealings with many thermistors as sensors on BMS
installations, probably 1,000+ on one site, sensing from 4 to 100 degC
approximately. I do not recall that they went ever wrong, but they
seem to be a source of constant failures on domestic freezers and
fridges, which are then scrapped because the "Engineer" can't replace
them or his labour charges make the replacement of a £30 thermistor
uneconomic. If the thermistors fail so frequently, surely the
encapsulation must be defective? There's nothing else to go wrong,
SFAIK.

Or is this engineered-in failure to ensure a constant demand for
replacements?


Yes. One wonders...

The 'trunking' panel at the inside rear of the freezer appears to be
fixed in place with just four screws - two at the top and two at the
bottom. I did not attempt to remove it for the de-frost, but if the unit
starts playing up again I will do so and see what I can determine!



--
Kev

Justice? You get justice in the next world,
in this world you have the law...
William Gaddis

"Andy Wade" wrote in message ...

On 31/10/2011 11:30, Ret. wrote:

Hmmm.. Having done a bit more Googling on the subject, it appears that I
may not be out of the woods yet - and if the evaporator is icing up,
then that could be a symptom of a failed sensor or defrost timer...

.... or the defrost heater itself - a common fault.

--
Andy



It is possible that the thing was badly iced up due to the door being left
open or warm items being loaded in and the auto defrost just isn't quite up
to the job. I replaced a electro mechanical timer - for about £7

In article , Ret.
writes

The 'trunking' panel at the inside rear of the freezer appears to be
fixed in place with just four screws - two at the top and two at the
bottom. I did not attempt to remove it for the de-frost, but if the unit
starts playing up again I will do so and see what I can determine!

Whilst it is ice free, now might be the time to remove the panel to see
how it goes together.

In a similar spot with a Bosch frost free fridge freezer the amount of
ice stopped the evaporator cover coming off and the cover staying on
inhibited the defrosting. Hours of gentle heat from a distance with a
fan heater on low sorted it out (beware excessive heat and internal
panels melting).

Sounds like you have done your research, bear in mind that frost frees
need air circulation to work properly and not ice up so try to avoid
over filling the drawers/compartments.
--
fred
time for a new sig I think . . .

On Oct 31, 3:27*pm, "Ret." wrote:
On 31/10/2011 12:45, Onetap wrote:





On Oct 31, 11:30 am, *wrote:

Hmmm.. *Having done a bit more Googling on the subject, it appears that
I may not be out of the woods yet - and if the evaporator is icing up,
then that could be a symptom of a failed sensor or defrost timer...

I had a similar problem with a frost-free freezer recently. The
refrigerant system seemed to be working, though not shifting the heat.
I got an 'engineer' through Domestic& *General; he seemingly knew
nothing more than I did and levered the plastic trim off the back
(breaking it) *before leaving without fixing it , saying he'd consult
a colleague and ring back.

* He didn't ring back. Since it would be scrap if not fixed, I set
about it and after an hour of gentle prodding at the trim, got access
to the PCB and sensor connections through the front (NB there is no
access through the back). The two thermistors had very different
resistances. I repleaced one, with a manufacturers kit ( 30! For a NTC
thermistor!!) and it went.

* *The internet recommendation seems to be to avoid frost free
appliances.

* * I've had dealings with many *thermistors as sensors on BMS
installations, probably 1,000+ on one site, sensing from 4 to 100 degC
approximately. I do not recall that they went ever wrong, but they
seem to be a *source of constant failures on domestic freezers and
fridges, which are then scrapped because the "Engineer" can't replace
them or his labour charges make the replacement of a 30 thermistor
uneconomic. If the thermistors fail so frequently, surely the
encapsulation must be defective? There's nothing else to go wrong,
SFAIK.

* Or is this engineered-in failure to ensure a constant demand for
replacements?

Yes. One wonders...

The 'trunking' panel at the inside rear of the freezer appears to be
fixed in place with just four screws - two at the top and two at the
bottom. I did not attempt to remove it for the de-frost, but if the unit
starts playing up again I will do so and see what I can determine!

--
Kev

Justice? You get justice in the next world,
in this world you have the law...
William Gaddis- Hide quoted text -

- Show quoted text -

There are two systems of defrost. One with an electric heater and the
other with hot refrigerant gases. The latter has a solenoid valve
which opens and bypasses the capillary tube to effect a defrost.

On Mon, 31 Oct 2011 15:27:30 +0000, "Ret."
wrote:

The 'trunking' panel at the inside rear of the freezer appears to be
fixed in place with just four screws - two at the top and two at the
bottom. I did not attempt to remove it for the de-frost, but if the unit
starts playing up again I will do so and see what I can determine!

Unless you let it defrost for 24 hours or more in a warm room then you
will need to intervene again, maybe in a few weeks, sometimes a couple
of months.

Be aware that if it is iced up then the plastic will be frozen across
a large area to the evaporator fins. You need to warm the area with a
hair dryer for a good 10 minutes or more, moving quickly across the
surface to ensure the plastic doesn't distort. Once that is done you
can remove the panel and see the mess behind - usually a huge block of
ice encasing the evaporator.

My advice is to buy a Hotpoint cooker, wire it up, and keep the ice
cream in the oven compartment - make sure the temperature is set to
max. It will do a better job at keeping the ice cream frozen than any
of their freezer range.


--

On 31/10/2011 11:18, Ret. wrote:
Our 4 yr old Hotpoint frost-free freezer started playing up recently.
The 'Temp too high' light came on - and ice cream in the top drawer was
semi melted. Turned the temperature control down and the light went out
- but ice cream was still not as 'solid' as it should be.

Was on the point of calling out an engineer when I read an earlier post
on a similar problem. Someone pointed out that even though there is no
visible 'frost' inside the cabinet - the evaporator, hidden behind the
fan 'trunking', can become iced up and reduce the cooling efficiency.

So we did a 'de-frost' - and were surprised at the amount of water that
came out.

Turned the freezer back on - and it's working perfectly again. So thanks
to uk.d-i-y and contributors for saving me at the least a call-out charge!



Not sure if it was my post - certainly I have posted about FF.

We tried a couple of 'defrosts' which made a bit of a difference for a
while, but in the end it was only when we left ours off for 48 hours
that it made a permanent difference.

It was only 48 hours because we were away for a weekend; 36 hours would
probably have been enough.

On Oct 31, 12:45*pm, Onetap wrote:
On Oct 31, 11:30*am, "Ret." wrote:

Hmmm.. *Having done a bit more Googling on the subject, it appears that
I may not be out of the woods yet - and if the evaporator is icing up,
then that could be a symptom of a failed sensor or defrost timer...

I had a similar problem with a frost-free freezer recently. The
refrigerant system seemed to be working, though not shifting the heat.
I got an 'engineer' through Domestic & General; he seemingly knew
nothing more than I did and levered the plastic trim off the back
(breaking it) *before leaving without fixing it , saying he'd consult
a colleague and ring back.

*He didn't ring back. Since it would be scrap if not fixed, I set
about it and after an hour of gentle prodding at the trim, got access
to the PCB and sensor connections through the front (NB there is no
access through the back). The two thermistors had very different
resistances. I repleaced one, with a manufacturers kit (£30! For a NTC
thermistor!!) and it went.

* The internet recommendation seems to be to avoid frost free
appliances.

* *I've had dealings with many *thermistors as sensors on BMS
installations, probably 1,000+ on one site, sensing from 4 to 100 degC
approximately. I do not recall that they went ever wrong, but they
seem to be a *source of constant failures on domestic freezers and
fridges, which are then scrapped because the "Engineer" can't replace
them or his labour charges make the replacement of a £30 thermistor
uneconomic. If the thermistors fail so frequently, surely the
encapsulation must be defective? There's nothing else to go wrong,
SFAIK.

*Or is this engineered-in failure to ensure a constant demand for
replacements?

Doesn't that tend to be counter-productive in a society not locked
into defective management?

On 31/10/2011 12:45, Onetap wrote:
On Oct 31, 11:30 am, wrote:

I've had dealings with many thermistors as sensors on BMS
installations, probably 1,000+ on one site, sensing from 4 to 100 degC
approximately. I do not recall that they went ever wrong, but they
seem to be a source of constant failures on domestic freezers and
fridges, which are then scrapped because the "Engineer" can't replace
them or his labour charges make the replacement of a £30 thermistor
uneconomic. If the thermistors fail so frequently, surely the
encapsulation must be defective? There's nothing else to go wrong,
SFAIK.

Or is this engineered-in failure to ensure a constant demand for
replacements?

I wonder whether it is just poor specification. With a previous employer
we had repeated failures of combined humidity and temperature sensors in
bakery coolers - it turned out that the data sheet quoted a useable
temperature range, but didn't say that to achieve the lower end of it, a
low temperature version (with L appended to the part number) was
required, as the normal version's humidity sensor couldn't take the
lower temperatures.

We also had ongoing problems with infra-red flammable gas sensors in
printworks - in this case the gases passing through were checked by
comparison of absorbsion of IR by the gases against a that of a clean
sample. This involved pulsing the IR sources (two non-replaceable
filament lamps) 3 times a second and the designers/manufacturers hadn't
considered the bulb life when repeatedly switched! The units were
failing after 3 months and being replaced repeatedly under the 3 year
warranty. They eventually solved the problem by ramping the voltages up
and down.

SteveW

On Oct 31, 10:42*pm, Steve Walker -
family.me.uk wrote:

I wonder whether it is just poor specification. With a previous employer
we had repeated failures of combined humidity and temperature sensors in
bakery coolers - it turned out that the data sheet quoted a useable
temperature range, but didn't say that to achieve the lower end of it, a
low temperature version (with L appended to the part number) was
required, as the normal version's humidity sensor couldn't take the
lower temperatures.

I'd think it probably is, I looked at a thermistor catalogue and you
can get specials for low temperature with different encapsulation.

BMS humidity sensors used to be unreliable, they aquired a big error
if exposed to very high humidity. Later versions were much more
reliable. Thermistors were generally fairly bullet-proof, IIRC.

On 31/10/2011 19:34, harry wrote:
On Oct 31, 3:27 pm, wrote:
On 31/10/2011 12:45, Onetap wrote:





On Oct 31, 11:30 am, wrote:

Hmmm.. Having done a bit more Googling on the subject, it appears that
I may not be out of the woods yet - and if the evaporator is icing up,
then that could be a symptom of a failed sensor or defrost timer...

I had a similar problem with a frost-free freezer recently. The
refrigerant system seemed to be working, though not shifting the heat.
I got an 'engineer' through Domestic& General; he seemingly knew
nothing more than I did and levered the plastic trim off the back
(breaking it) before leaving without fixing it , saying he'd consult
a colleague and ring back.

He didn't ring back. Since it would be scrap if not fixed, I set
about it and after an hour of gentle prodding at the trim, got access
to the PCB and sensor connections through the front (NB there is no
access through the back). The two thermistors had very different
resistances. I repleaced one, with a manufacturers kit ( 30! For a NTC
thermistor!!) and it went.

The internet recommendation seems to be to avoid frost free
appliances.

I've had dealings with many thermistors as sensors on BMS
installations, probably 1,000+ on one site, sensing from 4 to 100 degC
approximately. I do not recall that they went ever wrong, but they
seem to be a source of constant failures on domestic freezers and
fridges, which are then scrapped because the "Engineer" can't replace
them or his labour charges make the replacement of a 30 thermistor
uneconomic. If the thermistors fail so frequently, surely the
encapsulation must be defective? There's nothing else to go wrong,
SFAIK.

Or is this engineered-in failure to ensure a constant demand for
replacements?

Yes. One wonders...

The 'trunking' panel at the inside rear of the freezer appears to be
fixed in place with just four screws - two at the top and two at the
bottom. I did not attempt to remove it for the de-frost, but if the unit
starts playing up again I will do so and see what I can determine!

--
Kev

Justice? You get justice in the next world,
in this world you have the law...
William Gaddis- Hide quoted text -

- Show quoted text -

There are two systems of defrost. One with an electric heater and the
other with hot refrigerant gases. The latter has a solenoid valve
which opens and bypasses the capillary tube to effect a defrost.

OK. Thanks for that. I have no idea which system my Hotpoint uses. It is
a Hotpoint 'Future' FAZ50.

--
Kev

Justice? You get justice in the next world,
in this world you have the law...
William Gaddis

On 31/10/2011 19:46, The Other Mike wrote:
On Mon, 31 Oct 2011 15:27:30 +0000,
wrote:

The 'trunking' panel at the inside rear of the freezer appears to be
fixed in place with just four screws - two at the top and two at the
bottom. I did not attempt to remove it for the de-frost, but if the unit
starts playing up again I will do so and see what I can determine!

Unless you let it defrost for 24 hours or more in a warm room then you
will need to intervene again, maybe in a few weeks, sometimes a couple
of months.

Be aware that if it is iced up then the plastic will be frozen across
a large area to the evaporator fins. You need to warm the area with a
hair dryer for a good 10 minutes or more, moving quickly across the
surface to ensure the plastic doesn't distort. Once that is done you
can remove the panel and see the mess behind - usually a huge block of
ice encasing the evaporator.

My advice is to buy a Hotpoint cooker, wire it up, and keep the ice
cream in the oven compartment - make sure the temperature is set to
max. It will do a better job at keeping the ice cream frozen than any
of their freezer range.




LOL! Oh dear...

--
Kev

Justice? You get justice in the next world,
in this world you have the law...
William Gaddis

On 31/10/2011 17:37, DerbyBoy wrote:


"Andy Wade" wrote in message ...

On 31/10/2011 11:30, Ret. wrote:

Hmmm.. Having done a bit more Googling on the subject, it appears that I
may not be out of the woods yet - and if the evaporator is icing up,
then that could be a symptom of a failed sensor or defrost timer...

... or the defrost heater itself - a common fault.


OK. Only time will tell...

--
Kev

Justice? You get justice in the next world,
in this world you have the law...
William Gaddis