I have a Bosch full height upright freezer that is (meant to be) frost
free. It has the evaporator at the top and a fan blows air around the
cabinet to freezer the contents. Normally as good as good and anytime
you look at the evaporator it is either completely clear or the
slightest film of frost visible.

How do these things work? I assume that there is an electrical heater on
the evaporator that comes on after the compressor switches off to melt
the frost and the water drains away. If there is cooling demand, it
either abandons the defrost if unfinished or perhaps allows it to finish
and then commences cooling?

Am I on track?

The problem is that I noticed that the frost had built up seriously a
few weeks back and the temperature was rising inside. We *think* that
the door had got left ajar but no-one will confess to this.
I then spent some time playing a hot air gun over the evaporator melted
all the visible frost and after switching back on normal temperature was
achieved.

But slowly over a period of weeks, the frost has been building up but
the temperature has been maintained ok.

I can imagine a conflict between the defrost process and the demand for
cooling. Maybe the defrost part uses a 'just above zero" temp sensor to
signify frost clear and that is conflicting with the cooling cycle?

I wonder if the heating cooling algorithm can't cope with the remains of
ice that I did not melt away fully and it is slowly building up again or
perhaps if the heating element has failed.

In normal use (without the door being left ajar!) the only source of
frost should be a bit of warm air let in when the door opens and so it
does not need a huge defrost capability.

I have had one suggestion of letting the whole thing defrost naturally
over a couple of days, but the trouble is that it holds the vast
proportion of our frozen food stock and we would need a dedicated
feeding frenzy over several weeks to empty the thing.

Thanks if you have read this far!
Any suggestions please folks?

You summarised it quite well - My daughter had one (not Bosch) and I had to
replace the timer as a gear had stripped I recall.

http://www.ebay.co.uk/itm/Supco-Univ...eezer-Defrost-
Timer/282165782144?epid=1465909042&hash=item41b2642680%3 Ag%
3AtMoAAOSwgmJX0DkL



http://tinyurl.com/y7egqbbq

This and other videos will reveal the operation:

https://www.youtube.com/watch?v=-L80Fk5had4

"Chris Hogg" wrote in message
...
On Fri, 29 Sep 2017 17:30:52 +0100, Bob Minchin
wrote:


I have a Bosch full height upright freezer that is (meant to be) frost
free. It has the evaporator at the top and a fan blows air around the
cabinet to freezer the contents. Normally as good as good and anytime
you look at the evaporator it is either completely clear or the
slightest film of frost visible.

How do these things work? I assume that there is an electrical heater on
the evaporator that comes on after the compressor switches off to melt
the frost and the water drains away. If there is cooling demand, it
either abandons the defrost if unfinished or perhaps allows it to finish
and then commences cooling?

Am I on track?

The problem is that I noticed that the frost had built up seriously a
few weeks back and the temperature was rising inside. We *think* that
the door had got left ajar but no-one will confess to this.
I then spent some time playing a hot air gun over the evaporator melted
all the visible frost and after switching back on normal temperature was
achieved.

But slowly over a period of weeks, the frost has been building up but
the temperature has been maintained ok.

I can imagine a conflict between the defrost process and the demand for
cooling. Maybe the defrost part uses a 'just above zero" temp sensor to
signify frost clear and that is conflicting with the cooling cycle?

I wonder if the heating cooling algorithm can't cope with the remains of
ice that I did not melt away fully and it is slowly building up again or
perhaps if the heating element has failed.

In normal use (without the door being left ajar!) the only source of
frost should be a bit of warm air let in when the door opens and so it
does not need a huge defrost capability.

I have had one suggestion of letting the whole thing defrost naturally
over a couple of days, but the trouble is that it holds the vast
proportion of our frozen food stock and we would need a dedicated
feeding frenzy over several weeks to empty the thing.

Thanks if you have read this far!
Any suggestions please folks?

Two thoughts.

1 - you have a leaking door seal (or a leak elsewhere) that
slowly allows moist air from the room into the freezer,

Sounds unlikely given that it must be moving
air from outside into the inside in normal use,
not just moving the air around inside.

or the door isn't shutting properly (BTDT etc).

Ditto.

2 - to defrost it, get a _large_ cardboard box and line it with sheets
of polystyrene, say 1" or more thick, bottom, sides, and a panel for
the top, all cut to size and close fitting. Freeze several plastic
bottles of water, or get a good collection of ice packs / freezer
packs, and freeze them. Put them in the box, along with the contents
of the freezer. Repeat until freezer is empty, then turn freezer off,
leave the door open, perhaps direct a fan heater into it set on 'low',
and put plenty of old towels in the bottom and on the floor in front
of it to mop up the melt-water.

The cardboard box/boxes will keep the stuff cold for long enough to
allow the freezer to defrost.

More likely the control system isnt doing what it should for some reason.

Bob Minchin wrote:
I have a Bosch full height upright freezer that is (meant to be) frost
free. It has the evaporator at the top and a fan blows air around the
cabinet to freezer the contents. Normally as good as good and anytime
you look at the evaporator it is either completely clear or the
slightest film of frost visible.

How do these things work? I assume that there is an electrical heater
on the evaporator that comes on after the compressor switches off to
melt the frost and the water drains away. If there is cooling demand,
it either abandons the defrost if unfinished or perhaps allows it to
finish and then commences cooling?

Am I on track?


The problem is that I noticed that the frost had built up seriously a
few weeks back and the temperature was rising inside. We *think* that
the door had got left ajar but no-one will confess to this.
I then spent some time playing a hot air gun over the evaporator
melted all the visible frost and after switching back on normal
temperature was achieved.

But slowly over a period of weeks, the frost has been building up but
the temperature has been maintained ok.

I can imagine a conflict between the defrost process and the demand
for cooling. Maybe the defrost part uses a 'just above zero" temp
sensor to signify frost clear and that is conflicting with the
cooling cycle?
I wonder if the heating cooling algorithm can't cope with the remains
of ice that I did not melt away fully and it is slowly building up
again or perhaps if the heating element has failed.

In normal use (without the door being left ajar!) the only source of
frost should be a bit of warm air let in when the door opens and so it
does not need a huge defrost capability.

I have had one suggestion of letting the whole thing defrost naturally
over a couple of days, but the trouble is that it holds the vast
proportion of our frozen food stock and we would need a dedicated
feeding frenzy over several weeks to empty the thing.

Thanks if you have read this far!
Any suggestions please folks?

If you can, take the cover off the evaporator plate and see if it is all
frozen up inside. If it is, the timer could be the fault. Maybe.
There should be/might be little white plastic plugs holding the cover in
place.

DerbyBorn wrote:
You summarised it quite well - My daughter had one (not Bosch) and I had to
replace the timer as a gear had stripped I recall.

Thanks DB
I'm not sure if mine has a timer module or if it is electronic. The
badge on the front says "computer control" but that could be marketing
garbage.
I'll have to drag it out from the wall and see if there is a module
round the back.
I'll spend some time on YouTube thanks for the prompt. I should know
that nearly everything appears there.

Bob

Mr Pounder Esquire wrote:


If you can, take the cover off the evaporator plate and see if it is all
frozen up inside. If it is, the timer could be the fault. Maybe.
There should be/might be little white plastic plugs holding the cover in
place.


The evaporator seems to be just tubes and fins with air blown through. I
have a hunch that my hot air defrosting is just melting a little ice
which then drips down onto other ice and freezes again.

I'll try looking at the control board again. It has a couple of triacs
on it and I suspect they switch the fan and the heater.

If I can be certain which is the defrost heater, I might be able to
power that up manually, leave the freezer loaded but switched off and
accelerate the defrost process? Worth a go I reckon.

Bob

On 29/09/2017 19:10, Mr Pounder Esquire wrote:
Bob Minchin wrote:
I have a Bosch full height upright freezer that is (meant to be) frost
free. It has the evaporator at the top and a fan blows air around the
cabinet to freezer the contents. Normally as good as good and anytime
you look at the evaporator it is either completely clear or the
slightest film of frost visible.

How do these things work? I assume that there is an electrical heater
on the evaporator that comes on after the compressor switches off to
melt the frost and the water drains away. If there is cooling demand,
it either abandons the defrost if unfinished or perhaps allows it to
finish and then commences cooling?

Am I on track?


The problem is that I noticed that the frost had built up seriously a
few weeks back and the temperature was rising inside. We *think* that
the door had got left ajar but no-one will confess to this.
I then spent some time playing a hot air gun over the evaporator
melted all the visible frost and after switching back on normal
temperature was achieved.

But slowly over a period of weeks, the frost has been building up but
the temperature has been maintained ok.

I can imagine a conflict between the defrost process and the demand
for cooling. Maybe the defrost part uses a 'just above zero" temp
sensor to signify frost clear and that is conflicting with the
cooling cycle?
I wonder if the heating cooling algorithm can't cope with the remains
of ice that I did not melt away fully and it is slowly building up
again or perhaps if the heating element has failed.

In normal use (without the door being left ajar!) the only source of
frost should be a bit of warm air let in when the door opens and so it
does not need a huge defrost capability.

I have had one suggestion of letting the whole thing defrost naturally
over a couple of days, but the trouble is that it holds the vast
proportion of our frozen food stock and we would need a dedicated
feeding frenzy over several weeks to empty the thing.

Thanks if you have read this far!
Any suggestions please folks?

If you can, take the cover off the evaporator plate and see if it is all
frozen up inside. If it is, the timer could be the fault. Maybe.
There should be/might be little white plastic plugs holding the cover in
place.

That is what I have done to a frost free freezer a long while ago. I now
avoid them.

If you can remove the rear panel inside the freezer then investigate and
thaw all the ice you can see. The plastic doesn't take much heat so be
careful.

Some posters have mentioned control and timer systems, but once the heat
exchanger is clogged with ice, no heating (frost free) cycle seems able
to clear it.

Bob Minchin wrote:
Mr Pounder Esquire wrote:


If you can, take the cover off the evaporator plate and see if it is
all frozen up inside. If it is, the timer could be the fault. Maybe.
There should be/might be little white plastic plugs holding the
cover in place.


The evaporator seems to be just tubes and fins with air blown
through. I have a hunch that my hot air defrosting is just melting a
little ice which then drips down onto other ice and freezes again.

I called it a plate in error. Frost free do indeed have tubes and fins with
a fan blower motor. My experience with refrigeration ended in 1999.
So you did take the cover off then?


I'll try looking at the control board again. It has a couple of triacs
on it and I suspect they switch the fan and the heater.

If I can be certain which is the defrost heater, I might be able to
power that up manually, leave the freezer loaded but switched off and
accelerate the defrost process? Worth a go I reckon.

Bob

Fredxxx wrote:
On 29/09/2017 19:10, Mr Pounder Esquire wrote:
Bob Minchin wrote:
I have a Bosch full height upright freezer that is (meant to be)
frost free. It has the evaporator at the top and a fan blows air
around the cabinet to freezer the contents. Normally as good as
good and anytime you look at the evaporator it is either completely
clear or the slightest film of frost visible.

How do these things work? I assume that there is an electrical
heater on the evaporator that comes on after the compressor
switches off to melt the frost and the water drains away. If there
is cooling demand, it either abandons the defrost if unfinished or
perhaps allows it to finish and then commences cooling?

Am I on track?


The problem is that I noticed that the frost had built up seriously
a few weeks back and the temperature was rising inside. We *think*
that the door had got left ajar but no-one will confess to this.
I then spent some time playing a hot air gun over the evaporator
melted all the visible frost and after switching back on normal
temperature was achieved.

But slowly over a period of weeks, the frost has been building up
but the temperature has been maintained ok.

I can imagine a conflict between the defrost process and the demand
for cooling. Maybe the defrost part uses a 'just above zero" temp
sensor to signify frost clear and that is conflicting with the
cooling cycle?
I wonder if the heating cooling algorithm can't cope with the
remains of ice that I did not melt away fully and it is slowly
building up again or perhaps if the heating element has failed.

In normal use (without the door being left ajar!) the only source of
frost should be a bit of warm air let in when the door opens and so
it does not need a huge defrost capability.

I have had one suggestion of letting the whole thing defrost
naturally over a couple of days, but the trouble is that it holds
the vast proportion of our frozen food stock and we would need a
dedicated feeding frenzy over several weeks to empty the thing.

Thanks if you have read this far!
Any suggestions please folks?

If you can, take the cover off the evaporator plate and see if it is
all frozen up inside. If it is, the timer could be the fault. Maybe.
There should be/might be little white plastic plugs holding the
cover in place.

That is what I have done to a frost free freezer a long while ago. I
now avoid them.

New home fully modernised 9 years ago. There was no way a frost free fridge
freezer was going in there.
My conventional fridge freezer is set on Number 2 and works fine. The
compressor is very quiet and does not run for too long. I am aware that the
thermostat is getting to the end of its life, but I can get one from the net
for about 10 quid. Dead easy to fit.

If you can remove the rear panel inside the freezer then investigate
and thaw all the ice you can see. The plastic doesn't take much heat
so be careful.

Some posters have mentioned control and timer systems, but once the
heat exchanger is clogged with ice, no heating (frost free) cycle
seems able to clear it.

Yip.

Mr Pounder Esquire wrote:
Bob Minchin wrote:
Mr Pounder Esquire wrote:


If you can, take the cover off the evaporator plate and see if it is
all frozen up inside. If it is, the timer could be the fault. Maybe.
There should be/might be little white plastic plugs holding the
cover in place.


The evaporator seems to be just tubes and fins with air blown
through. I have a hunch that my hot air defrosting is just melting a
little ice which then drips down onto other ice and freezes again.

I called it a plate in error. Frost free do indeed have tubes and fins with
a fan blower motor. My experience with refrigeration ended in 1999.
So you did take the cover off then?


I'll try looking at the control board again. It has a couple of triacs
on it and I suspect they switch the fan and the heater.

If I can be certain which is the defrost heater, I might be able to
power that up manually, leave the freezer loaded but switched off and
accelerate the defrost process? Worth a go I reckon.

Bob



Yes the front cover is off exposing about 5 individual plugs, one of
which I'm pretty convinced is the defrost heater having looked at
pictures of replacement one.
One pair of connections measures 280 ohms or about 200 watts on 240v
which seems about right for the job.

Bob Minchin wrote:
Mr Pounder Esquire wrote:
Bob Minchin wrote:
Mr Pounder Esquire wrote:


If you can, take the cover off the evaporator plate and see if it
is all frozen up inside. If it is, the timer could be the fault.
Maybe. There should be/might be little white plastic plugs holding
the cover in place.


The evaporator seems to be just tubes and fins with air blown
through. I have a hunch that my hot air defrosting is just melting a
little ice which then drips down onto other ice and freezes again.

I called it a plate in error. Frost free do indeed have tubes and
fins with a fan blower motor. My experience with refrigeration ended
in 1999. So you did take the cover off then?


I'll try looking at the control board again. It has a couple of
triacs on it and I suspect they switch the fan and the heater.

If I can be certain which is the defrost heater, I might be able to
power that up manually, leave the freezer loaded but switched off
and accelerate the defrost process? Worth a go I reckon.

Bob



Yes the front cover is off exposing about 5 individual plugs, one of
which I'm pretty convinced is the defrost heater having looked at
pictures of replacement one.
One pair of connections measures 280 ohms or about 200 watts on 240v
which seems about right for the job.

Not all frozen up then?

On 29/09/2017 18:28, Chris Hogg wrote:
On Fri, 29 Sep 2017 17:30:52 +0100, Bob Minchin
wrote:


I have a Bosch full height upright freezer that is (meant to be) frost
free. It has the evaporator at the top and a fan blows air around the
cabinet to freezer the contents. Normally as good as good and anytime
you look at the evaporator it is either completely clear or the
slightest film of frost visible.

How do these things work? I assume that there is an electrical heater on
the evaporator that comes on after the compressor switches off to melt
the frost and the water drains away. If there is cooling demand, it
either abandons the defrost if unfinished or perhaps allows it to finish
and then commences cooling?

Am I on track?

The problem is that I noticed that the frost had built up seriously a
few weeks back and the temperature was rising inside. We *think* that
the door had got left ajar but no-one will confess to this.
I then spent some time playing a hot air gun over the evaporator melted
all the visible frost and after switching back on normal temperature was
achieved.

But slowly over a period of weeks, the frost has been building up but
the temperature has been maintained ok.

I can imagine a conflict between the defrost process and the demand for
cooling. Maybe the defrost part uses a 'just above zero" temp sensor to
signify frost clear and that is conflicting with the cooling cycle?

I wonder if the heating cooling algorithm can't cope with the remains of
ice that I did not melt away fully and it is slowly building up again or
perhaps if the heating element has failed.

In normal use (without the door being left ajar!) the only source of
frost should be a bit of warm air let in when the door opens and so it
does not need a huge defrost capability.

I have had one suggestion of letting the whole thing defrost naturally
over a couple of days, but the trouble is that it holds the vast
proportion of our frozen food stock and we would need a dedicated
feeding frenzy over several weeks to empty the thing.

Thanks if you have read this far!
Any suggestions please folks?

Two thoughts.

1 - you have a leaking door seal (or a leak elsewhere) that slowly
allows moist air from the room into the freezer, or the door isn't
shutting properly (BTDT etc).

2 - to defrost it, get a _large_ cardboard box and line it with sheets
of polystyrene, say 1" or more thick, bottom, sides, and a panel for
the top, all cut to size and close fitting. Freeze several plastic
bottles of water, or get a good collection of ice packs / freezer
packs, and freeze them. Put them in the box, along with the contents
of the freezer. Repeat until freezer is empty, then turn freezer off,
leave the door open, perhaps direct a fan heater into it set on 'low',
and put plenty of old towels in the bottom and on the floor in front
of it to mop up the melt-water.

The cardboard box/boxes will keep the stuff cold for long enough to
allow the freezer to defrost.

Rather than carboard boxes, I have used the fridge, which is much easier
and quicker than the freezer to empty by eating everything - especially
if done at the right time of the week.

If there is a removeable panel in the back of the freezer, a hairdryer
or a steam wallpaper stripper will soon clear any ice behind it.

Make sure that the drain is completely clear. Any ice in there will
cause a continual build-up when the water from the heating cycle of the
frost-free function cannot drain to the evaporation tray.

SteveW

Bob Minchin wrote in
news
DerbyBorn wrote:
You summarised it quite well - My daughter had one (not Bosch) and I
had to replace the timer as a gear had stripped I recall.

Thanks DB
I'm not sure if mine has a timer module or if it is electronic. The
badge on the front says "computer control" but that could be marketing
garbage.
I'll have to drag it out from the wall and see if there is a module
round the back.
I'll spend some time on YouTube thanks for the prompt. I should know
that nearly everything appears there.

Bob


They can get overwhelmed with ice due to an "incident" and then the defrost
time doesn't quite clear it. A full manual fefrost is the way to go.

I had an old appliance which developed bad contacts on the
mechanical time switch for the defrost cycle. For a while it was
fixable, but eventually needed replacement.

It had a secondary related problem in that the drain tube (which,
as seems usual, ran to a plastic tray on top of the compressor)
had become blocked, so the melted ice was not draining away.

This leads to another caution - if you have had to do a serious
manual defrost, the amount of water liberated will most likely be
more than the catch tray can hold, so will probably overflow onto
your flooring.

Chris
--
Chris J Dixon Nottingham UK


Plant amazing Acers.

Bunged up drain hole to the evaporator tray?
I had this on a Fridgemaster on. Unbunged it with a bit of stiff wire and
no further build up I have to say though that these seem to be a bit of a
black art sometimes. Clearly they work but to get the balance correct
between removing the moisture and not letting it thaw out completely always
seems counter intuitive.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Bob Minchin" wrote in message
news

I have a Bosch full height upright freezer that is (meant to be) frost
free. It has the evaporator at the top and a fan blows air around the
cabinet to freezer the contents. Normally as good as good and anytime you
look at the evaporator it is either completely clear or the slightest film
of frost visible.

How do these things work? I assume that there is an electrical heater on
the evaporator that comes on after the compressor switches off to melt the
frost and the water drains away. If there is cooling demand, it either
abandons the defrost if unfinished or perhaps allows it to finish and then
commences cooling?

Am I on track?

The problem is that I noticed that the frost had built up seriously a few
weeks back and the temperature was rising inside. We *think* that the door
had got left ajar but no-one will confess to this.
I then spent some time playing a hot air gun over the evaporator melted
all the visible frost and after switching back on normal temperature was
achieved.

But slowly over a period of weeks, the frost has been building up but the
temperature has been maintained ok.

I can imagine a conflict between the defrost process and the demand for
cooling. Maybe the defrost part uses a 'just above zero" temp sensor to
signify frost clear and that is conflicting with the cooling cycle?

I wonder if the heating cooling algorithm can't cope with the remains of
ice that I did not melt away fully and it is slowly building up again or
perhaps if the heating element has failed.

In normal use (without the door being left ajar!) the only source of frost
should be a bit of warm air let in when the door opens and so it does not
need a huge defrost capability.

I have had one suggestion of letting the whole thing defrost naturally
over a couple of days, but the trouble is that it holds the vast
proportion of our frozen food stock and we would need a dedicated feeding
frenzy over several weeks to empty the thing.

Thanks if you have read this far!
Any suggestions please folks?

Mr Pounder Esquire wrote:
Bob Minchin wrote:
Mr Pounder Esquire wrote:
Bob Minchin wrote:
Mr Pounder Esquire wrote:


If you can, take the cover off the evaporator plate and see if it
is all frozen up inside. If it is, the timer could be the fault.
Maybe. There should be/might be little white plastic plugs holding
the cover in place.


The evaporator seems to be just tubes and fins with air blown
through. I have a hunch that my hot air defrosting is just melting a
little ice which then drips down onto other ice and freezes again.

I called it a plate in error. Frost free do indeed have tubes and
fins with a fan blower motor. My experience with refrigeration ended
in 1999. So you did take the cover off then?


I'll try looking at the control board again. It has a couple of
triacs on it and I suspect they switch the fan and the heater.

If I can be certain which is the defrost heater, I might be able to
power that up manually, leave the freezer loaded but switched off
and accelerate the defrost process? Worth a go I reckon.

Bob



Yes the front cover is off exposing about 5 individual plugs, one of
which I'm pretty convinced is the defrost heater having looked at
pictures of replacement one.
One pair of connections measures 280 ohms or about 200 watts on 240v
which seems about right for the job.

Not all frozen up then?


Correct. As per my original post, the evaporator is gradually icing up
over a few weeks. I am becoming convinced that a good defrost will sort
it out but will try direct connection to the defrost heater with the
contents inside and a thermometer monitoring the contents temperature.

"Brian Gaff" wrote in message
news
Bunged up drain hole to the evaporator tray?
I had this on a Fridgemaster on. Unbunged it with a bit of stiff wire and
no further build up I have to say though that these seem to be a bit of a
black art sometimes. Clearly they work but to get the balance correct
between removing the moisture and not letting it thaw out completely
always seems counter intuitive.

Not when its just defrosting where the frost collects with a frost free.

"Bob Minchin" wrote in message
news

I have a Bosch full height upright freezer that is (meant to be) frost
free. It has the evaporator at the top and a fan blows air around the
cabinet to freezer the contents. Normally as good as good and anytime you
look at the evaporator it is either completely clear or the slightest
film of frost visible.

How do these things work? I assume that there is an electrical heater on
the evaporator that comes on after the compressor switches off to melt
the frost and the water drains away. If there is cooling demand, it
either abandons the defrost if unfinished or perhaps allows it to finish
and then commences cooling?

Am I on track?

The problem is that I noticed that the frost had built up seriously a few
weeks back and the temperature was rising inside. We *think* that the
door had got left ajar but no-one will confess to this.
I then spent some time playing a hot air gun over the evaporator melted
all the visible frost and after switching back on normal temperature was
achieved.

But slowly over a period of weeks, the frost has been building up but the
temperature has been maintained ok.

I can imagine a conflict between the defrost process and the demand for
cooling. Maybe the defrost part uses a 'just above zero" temp sensor to
signify frost clear and that is conflicting with the cooling cycle?

I wonder if the heating cooling algorithm can't cope with the remains of
ice that I did not melt away fully and it is slowly building up again or
perhaps if the heating element has failed.

In normal use (without the door being left ajar!) the only source of
frost should be a bit of warm air let in when the door opens and so it
does not need a huge defrost capability.

I have had one suggestion of letting the whole thing defrost naturally
over a couple of days, but the trouble is that it holds the vast
proportion of our frozen food stock and we would need a dedicated feeding
frenzy over several weeks to empty the thing.

Thanks if you have read this far!
Any suggestions please folks?

On 29/09/2017 17:30, Bob Minchin wrote:

I have a Bosch full height upright freezer that is (meant to be) frost
free. It has the evaporator at the top and a fan blows air around the
cabinet to freezer the contents. Normally as good as good and anytime
you look at the evaporator it is either completely clear or the
slightest film of frost visible.

How do these things work? I assume that there is an electrical heater on
the evaporator that comes on after the compressor switches off to melt
the frost and the water drains away. If there is cooling demand, it
either abandons the defrost if unfinished or perhaps allows it to finish
and then commences cooling?

Am I on track?

The problem is that I noticed that the frost had built up seriously a
few weeks back and the temperature was rising inside. We *think* that
the door had got left ajar but no-one will confess to this.
I then spent some time playing a hot air gun over the evaporator melted
all the visible frost and after switching back on normal temperature was
achieved.

But slowly over a period of weeks, the frost has been building up but
the temperature has been maintained ok.

I can imagine a conflict between the defrost process and the demand for
cooling. Maybe the defrost part uses a 'just above zero" temp sensor to
signify frost clear and that is conflicting with the cooling cycle?

I wonder if the heating cooling algorithm can't cope with the remains of
ice that I did not melt away fully and it is slowly building up again or
perhaps if the heating element has failed.

In normal use (without the door being left ajar!) the only source of
frost should be a bit of warm air let in when the door opens and so it
does not need a huge defrost capability.

I have had one suggestion of letting the whole thing defrost naturally
over a couple of days, but the trouble is that it holds the vast
proportion of our frozen food stock and we would need a dedicated
feeding frenzy over several weeks to empty the thing.

Thanks if you have read this far!
Any suggestions please folks?


We had this some years back on a Whirlpool- it took their engineers ages
to fix it - it was a simple timer sticking. We lost several freezer
loads of food, it cost Whirlpool a fortunate.

As for defrosting manually, we 'turn around' ours in half a day or so.
We have several freezers (we stock up on meat, fish etc at CostCo) and
run one down so we can defrost one.




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Benefit or Personal Independence Payment when they don't need it? They
are depriving those in real need!

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Brian Reay wrote:
On 29/09/2017 17:30, Bob Minchin wrote:

I have a Bosch full height upright freezer that is (meant to be)
frost free. It has the evaporator at the top and a fan blows air
around the cabinet to freezer the contents. Normally as good as good
and anytime you look at the evaporator it is either completely clear
or the slightest film of frost visible.

How do these things work? I assume that there is an electrical
heater on the evaporator that comes on after the compressor switches
off to melt the frost and the water drains away. If there is cooling
demand, it either abandons the defrost if unfinished or perhaps
allows it to finish and then commences cooling?

Am I on track?

The problem is that I noticed that the frost had built up seriously a
few weeks back and the temperature was rising inside. We *think* that
the door had got left ajar but no-one will confess to this.
I then spent some time playing a hot air gun over the evaporator
melted all the visible frost and after switching back on normal
temperature was achieved.

But slowly over a period of weeks, the frost has been building up but
the temperature has been maintained ok.

I can imagine a conflict between the defrost process and the demand
for cooling. Maybe the defrost part uses a 'just above zero" temp
sensor to signify frost clear and that is conflicting with the
cooling cycle? I wonder if the heating cooling algorithm can't cope with
the
remains of ice that I did not melt away fully and it is slowly
building up again or perhaps if the heating element has failed.

In normal use (without the door being left ajar!) the only source of
frost should be a bit of warm air let in when the door opens and so
it does not need a huge defrost capability.

I have had one suggestion of letting the whole thing defrost
naturally over a couple of days, but the trouble is that it holds
the vast proportion of our frozen food stock and we would need a
dedicated feeding frenzy over several weeks to empty the thing.

Thanks if you have read this far!
Any suggestions please folks?


We had this some years back on a Whirlpool- it took their engineers
ages to fix it - it was a simple timer sticking. We lost several
freezer loads of food, it cost Whirlpool a fortunate.

As for defrosting manually, we 'turn around' ours in half a day or
so. We have several freezers (we stock up on meat, fish etc at
CostCo) and run one down so we can defrost one.

I defrost our conventional fridge freezer four times per year using a hair
dryer. It takes less than 30 minutes to do this and gives me the chance to
clean all of the drawers, chuck out of date stuff and clean the inside of
the cabinet and the seals. People with frost free will probably not clean
etc as they see no need. Sad is this.
There is no way that a frost free appliance will ever enter our kitchen.
Apart from insulation failure which is very rare these day there are two
things that can fail with my conventional fridge freezer - thermostat = £10
or less ---- compressor which is end of days.
Now, take a look at the workings of a frost free lump of ****
......................

"Mr Pounder Esquire" wrote in message
news
Brian Reay wrote:
On 29/09/2017 17:30, Bob Minchin wrote:

I have a Bosch full height upright freezer that is (meant to be)
frost free. It has the evaporator at the top and a fan blows air
around the cabinet to freezer the contents. Normally as good as good
and anytime you look at the evaporator it is either completely clear
or the slightest film of frost visible.

How do these things work? I assume that there is an electrical
heater on the evaporator that comes on after the compressor switches
off to melt the frost and the water drains away. If there is cooling
demand, it either abandons the defrost if unfinished or perhaps
allows it to finish and then commences cooling?

Am I on track?

The problem is that I noticed that the frost had built up seriously a
few weeks back and the temperature was rising inside. We *think* that
the door had got left ajar but no-one will confess to this.
I then spent some time playing a hot air gun over the evaporator
melted all the visible frost and after switching back on normal
temperature was achieved.

But slowly over a period of weeks, the frost has been building up but
the temperature has been maintained ok.

I can imagine a conflict between the defrost process and the demand
for cooling. Maybe the defrost part uses a 'just above zero" temp
sensor to signify frost clear and that is conflicting with the
cooling cycle? I wonder if the heating cooling algorithm can't cope with
the
remains of ice that I did not melt away fully and it is slowly
building up again or perhaps if the heating element has failed.

In normal use (without the door being left ajar!) the only source of
frost should be a bit of warm air let in when the door opens and so
it does not need a huge defrost capability.

I have had one suggestion of letting the whole thing defrost
naturally over a couple of days, but the trouble is that it holds
the vast proportion of our frozen food stock and we would need a
dedicated feeding frenzy over several weeks to empty the thing.

Thanks if you have read this far!
Any suggestions please folks?


We had this some years back on a Whirlpool- it took their engineers
ages to fix it - it was a simple timer sticking. We lost several
freezer loads of food, it cost Whirlpool a fortunate.

As for defrosting manually, we 'turn around' ours in half a day or
so. We have several freezers (we stock up on meat, fish etc at
CostCo) and run one down so we can defrost one.

I defrost our conventional fridge freezer four times per year using a hair
dryer. It takes less than 30 minutes to do this and gives me the chance to
clean all of the drawers, chuck out of date stuff and clean the inside of
the cabinet and the seals. People with frost free will probably not clean
etc as they see no need.

Yes, I don’t bother.

Sad is this.

Even sillier than you usually manage.

There is no way that a frost free appliance will ever enter our kitchen.

Yes, you are that terminal a ****wit.

Apart from insulation failure which is very rare these day there are two
things that can fail with my conventional fridge freezer - thermostat =
£10 or less ---- compressor which is end of days.

Havent had any of mine fail, ever.

Now, take a look at the workings of a frost free lump of ****

Mine have been fine for over a decade now.

Rod Speed wrote:
"Mr Pounder Esquire" wrote in message
news
Brian Reay wrote:
On 29/09/2017 17:30, Bob Minchin wrote:

I have a Bosch full height upright freezer that is (meant to be)
frost free. It has the evaporator at the top and a fan blows air
around the cabinet to freezer the contents. Normally as good as
good and anytime you look at the evaporator it is either
completely clear or the slightest film of frost visible.

How do these things work? I assume that there is an electrical
heater on the evaporator that comes on after the compressor
switches off to melt the frost and the water drains away. If there
is cooling demand, it either abandons the defrost if unfinished or
perhaps allows it to finish and then commences cooling?

Am I on track?

The problem is that I noticed that the frost had built up
seriously a few weeks back and the temperature was rising inside.
We *think* that the door had got left ajar but no-one will confess
to this. I then spent some time playing a hot air gun over the
evaporator
melted all the visible frost and after switching back on normal
temperature was achieved.

But slowly over a period of weeks, the frost has been building up
but the temperature has been maintained ok.

I can imagine a conflict between the defrost process and the demand
for cooling. Maybe the defrost part uses a 'just above zero" temp
sensor to signify frost clear and that is conflicting with the
cooling cycle? I wonder if the heating cooling algorithm can't
cope with the
remains of ice that I did not melt away fully and it is slowly
building up again or perhaps if the heating element has failed.

In normal use (without the door being left ajar!) the only source
of frost should be a bit of warm air let in when the door opens
and so it does not need a huge defrost capability.

I have had one suggestion of letting the whole thing defrost
naturally over a couple of days, but the trouble is that it holds
the vast proportion of our frozen food stock and we would need a
dedicated feeding frenzy over several weeks to empty the thing.

Thanks if you have read this far!
Any suggestions please folks?


We had this some years back on a Whirlpool- it took their engineers
ages to fix it - it was a simple timer sticking. We lost several
freezer loads of food, it cost Whirlpool a fortunate.

As for defrosting manually, we 'turn around' ours in half a day or
so. We have several freezers (we stock up on meat, fish etc at
CostCo) and run one down so we can defrost one.

I defrost our conventional fridge freezer four times per year using
a hair dryer. It takes less than 30 minutes to do this and gives me
the chance to clean all of the drawers, chuck out of date stuff and
clean the inside of the cabinet and the seals. People with frost
free will probably not clean etc as they see no need.

Yes, I don’t bother.

Sad is this.

Even sillier than you usually manage.

There is no way that a frost free appliance will ever enter our
kitchen.

Yes, you are that terminal a ****wit.

Apart from insulation failure which is very rare these day there are
two things that can fail with my conventional fridge freezer -
thermostat = £10 or less ---- compressor which is end of days.

Havent had any of mine fail, ever.

Now, take a look at the workings of a frost free lump of ****

Mine have been fine for over a decade now.

You have always been and always will be a stupid Australian ****.
Now, just go and kill yourself, you will not be missed.

On Friday, 29 September 2017 19:19:35 UTC+1, Bob Minchin wrote:
Mr Pounder Esquire wrote:

If you can, take the cover off the evaporator plate and see if it is all
frozen up inside. If it is, the timer could be the fault. Maybe.
There should be/might be little white plastic plugs holding the cover in
place.

The evaporator seems to be just tubes and fins with air blown through. I
have a hunch that my hot air defrosting is just melting a little ice
which then drips down onto other ice and freezes again.

I'll try looking at the control board again. It has a couple of triacs
on it and I suspect they switch the fan and the heater.

If I can be certain which is the defrost heater, I might be able to
power that up manually, leave the freezer loaded but switched off and
accelerate the defrost process? Worth a go I reckon.

Bob

a classic formula for a fire with a frost-free.

A 2 day defrost really is the first move. If the problem recurs, you may have a bad timer or defrosting element. The long term solution is to get a traditional freezer, that way you get to choose when to do the annual defrost instead of the freezer. And it lasts longer.


NT

wrote in message
...
On Friday, 29 September 2017 19:19:35 UTC+1, Bob Minchin wrote:
Mr Pounder Esquire wrote:

If you can, take the cover off the evaporator plate and see if it is
all
frozen up inside. If it is, the timer could be the fault. Maybe.
There should be/might be little white plastic plugs holding the cover
in
place.

The evaporator seems to be just tubes and fins with air blown through. I
have a hunch that my hot air defrosting is just melting a little ice
which then drips down onto other ice and freezes again.

I'll try looking at the control board again. It has a couple of triacs
on it and I suspect they switch the fan and the heater.

If I can be certain which is the defrost heater, I might be able to
power that up manually, leave the freezer loaded but switched off and
accelerate the defrost process? Worth a go I reckon.

Bob

a classic formula for a fire with a frost-free.

A 2 day defrost really is the first move. If the problem
recurs, you may have a bad timer or defrosting element.

The long term solution is to get a traditional freezer,

Only if you are actually stupid enough to want
to waste your time manually defrosting for the
rest of your life and have somewhere to put
the contents of the freezer while you defrost it.

that way you get to choose when to do
the annual defrost instead of the freezer.

I have never had to manually defrost
my frost free freezer or fridge either.

And it lasts longer.

I dont care.

wrote:
On Friday, 29 September 2017 19:19:35 UTC+1, Bob Minchin wrote:
Mr Pounder Esquire wrote:

If you can, take the cover off the evaporator plate and see if it is all
frozen up inside. If it is, the timer could be the fault. Maybe.
There should be/might be little white plastic plugs holding the cover in
place.

The evaporator seems to be just tubes and fins with air blown through. I
have a hunch that my hot air defrosting is just melting a little ice
which then drips down onto other ice and freezes again.

I'll try looking at the control board again. It has a couple of triacs
on it and I suspect they switch the fan and the heater.

If I can be certain which is the defrost heater, I might be able to
power that up manually, leave the freezer loaded but switched off and
accelerate the defrost process? Worth a go I reckon.

Bob

a classic formula for a fire with a frost-free.

A 2 day defrost really is the first move. If the problem recurs, you may have a bad timer or defrosting element. The long term solution is to get a traditional freezer, that way you get to choose when to do the annual defrost instead of the freezer. And it lasts longer.


NT

Well only if you think I'm daft enough to leave the defrost heater on
without monitoring it carefully. I did keep an eye on it as well as a
thermometer probe in with the food. I turned the heater off at -15C and
it is much improved now.
Overall I think you are correct in that a long term defrost will be the
complete cure. So we are working toward condensing/reducing our frozen
food stocks to take this one out of service for a couple of days.

In the meantime I shall devise a method of a much louder alarm than the
pathetic squeak it now gives out which can't be heard outside of the
utility room. I'll link it into the phone bell repeater system which
covers the house and workshops.