Could you please tell me which one is better electronics or mechanical time
r? I want a timer for my basement dehumidifier to turn it on/off for 3-4hrs
/day. I saw some timers and I was thinking about mechanical because I do no
t have to change battery etc since I might not be around to change the batt
ery. I have found this one from Lowes
But if you think electronics one is better and it can last working for 1 ye
ar without changing the battery then I will consider electronics timer.
Thanks a lot.
On Thursday, August 1, 2013 7:38:11 PM UTC-4, Frank wrote:
4hrs/day. I saw some timers and I was thinking about mechanical because I d
o not have to change battery etc since I might not be around to change the
battery. I have found this one from Lowes
There may be some electronic timers that use a battery to maintain
the clock for long periods with power loss, but agree, the one's
I've seen don't use batteries. Bigger issue is if the timer is
rated for just lights or motor loads like the dehumidifier. All
the mechanical ones probably are. The electronic ones, I'd suspect
many are not. If it were me, I'd just go with the mechanical.
Simple, easy and it works. Just programming the damn electronic
ones can be a PIA.
I have an electronic timer.
I use it to charge a spare car battery in my boiler room. I have a 6
amp trickle charger connected to a spare car battery, and the trickle
charger is plugged into my timer. Every day at 3:00 PM the timer
provides power to the trickle charger for 10 minutes. I've had car
batteries die on me in the past without any warning, so I keep a spare
battery charged and ready to go.
I like the electronic timers better than the mechanical ones for several
1. With a mechanical timer, you're "ON" time can't be less than 15 to 20
minutes or so because of the size of the trippers. Normally, that's not
a problem, but in my case it was. I was concerned about overcharging
the battery, and so I wanted to be able to have the "ON" time as short
as possible. My timer has a minimum "ON" time of one minute.
2. I was also a bit concerned about having to replace batteries, but
the timer I bought (for $8.00 at a Cargo Surplus store here in Winnipeg)
has a built in rechargeable battery. It charges itself off the same
power it switches. So, you never have to change the batteries in it,
and it'll still display the time and it's programmed settings for
several days after you unplug it.
3. I didn't have a clock in my boiler room. The electronic timer
displays the time of day, and so that's a handy feature to have in a
room which otherwise wouldn't have a clock.
On Thursday, August 1, 2013 6:14:06 PM UTC-5, leza wang wrote:
-4hrs/day. I saw some timers and I was thinking about mechanical because I
do not have to change battery etc since I might not be around to change the
battery. I have found this one from Lowes http://www.lowes.ca/timers-photo
Rvw But if you think electronics one is better and it can last working for
1 year without changing the battery then I will consider electronics timer.
Thanks a lot.
I would definitely prefer a mechanical timer. They don't fail (usually) if
there is any sort of power surge due to lightning or other things. They d
o have to be reset if there is a power failure and you want the on-off to o
ccur at a specific time. But for a general x hours on and y hours off, the
mechanical timer is definitely my choice.
On 8/1/2013 9:53 PM, firstname.lastname@example.org wrote:
I service electrical and electronic equipment and when I install new or
replace a failed mechanical timer, I'll install an electronic timer
every time. The important thing is to use a high quality commercial or
industrial timer. I've replaced too many mechanical timers that failed
because the mechanical components wear out. The little clock motor wears
out and they are replaceable but if a mechanical timer is old enough for
the motor to wear out, the mechanical parts are trashed too. For light
duty use by a homeowner and I mean light duty, a mechanical timer would
be simple to use but if it's going to be used 24/7-365, go with an
electronic timer especially if it's used for safety lighting. There is a
hybrid timer I like and it uses a clock mechanism like the electronic
analog clocks that use a single AA battery. The load switching is done
by a heavy duty relay not a mechanical pawl and micro switch which are
the most common points of failure in mechanical timers. ^_^
On Thu, 1 Aug 2013 19:53:28 -0700 (PDT), " email@example.com"
Yes, it doesn't matter when dehumidifying is done** unless the
electric company charges more at some times of day. But the user is
bound to notice if there was a power failure of any length, and she
can reset the clock. If the power failure is only 5 minutes, there is
no need to reset the clock.
**For the most part, but the only humidity problem would be if it ran
for 2 hours than right after that ran for 2 hours again, when there
wasn't enough humidity left to be worth it. But how could that
happen with a mechanical timer. Instead the next cycle would be
delayed as long as the power was out, not hastened.
***About 1950, my mother had fridge with a self-defrosting freezer.
However it never defrosted at the right time. That's because she
didn't read the instructions, and she set its clock for the time she
WANTED it to defrost, when it was supposed to be set for the current
time (and it would defrost at 2 in the morning.) So because she did
the time setting at various times, the defrost time jumped all around
the clock. By the time I read the instructions, she was moving and
selling the fridge iirc.
Probably none. I would much prefer determining time. The top freezer air
gets into the 20's during defrost, I've seen. If your opening the thing up
during this time, it's much worse. How many times I'm home with groceries,
and the thing is on defrost. The bottom fridge, door closed, fairs better.
I've data logged a couple units.
It's unsettling to open the door, the fan isn't running and the stuff is
getting warm. You kinda wonder if the dumb thing is broken.
Christopher A. Young
Learn about Jesus
On 8/2/2013 2:21 PM, firstname.lastname@example.org wrote:
On Fri, 2 Aug 2013 11:21:00 -0700 (PDT), " email@example.com"
She wanted it to defrost in the middle of the night, and indeed it was
built to do that. Had she set the clock for the current time, it
would have defrosted at 2 or maybe it was 3 or 4AM. Once a day.
This was probably a Crosley Shelvador. made about 1950..
AFAICR the clock was not in the freezer compartment of the fridge, but
more likely it was behind a panel on the bottom, was about 4x4" or
4x6" big, with a knob rather than hands, but a clock face behind the
Shelvador does not relate to Shelvador Dali but to the fact that it
was one of the first to have shelves on the door, eventuallly putting
twice as much food on the front line.
I see you can still buy one from 1952, restored, for $3200.
FWIW, my mother grew up with an ice box, and in the hot weather would
catch the guy on the ice wagon so he would give her and her friends
ice chips to suck on. Then she went through the stage where you had
to defrost the freezer, and she was very happy when we got this around
There was no fan blowing air out of the freezer. That didn't start
afaik until "frost-free" was invented, and iiuc, it's the fan that
makes it frost-free.
No, it's not the fan that makes the fridge "frost free".
It's the fact that the place where the refrigerant gets injected as a
high pressure liquid and evaporates into a vapour, absorbing heat as it
does, was moved from channels molded into the freezer compartment to a
special "evaporator coil" typically located in the back wall of the
And, that evaporator coil was accompanied by a defrost heater, defrost
termination switch, defrost timer, defrost pan with drain and a hose
that carried the melt water down to the bottom of the fridge where it
would re-evaporate into the ambient air. Together, all those parts
would automatically defrost the evaporator coil once a day or so so the
homeowner didn't have to defrost it.
And, of course, they added an evaporator fan to suck cold air through
that evaporator coil and blow it into the freezer compartment, and from
there some of the cold air would get sucked back over the evaporator
coil and some would get blown down into the fresh food section of the
fridge, keeping that space cool, too.
So, a frost free fridge operates on the same thermodynamic cycle that a
regular manual defrost fridge does... it's just that it's equipped with
all of the necessary equipment to defrost itself every 10 to 20 hours or
so. And that defrost cycle is governed by the defrost "timer", which is
the "Brains" of a frost free fridge.
Keep this in mind:
All frost free fridges that I know of have the compressor and evaporator
fan in parallel, with both in series with the thermostat. The other
circuit in the fridge will have the defrost heater in series with the
defrost thermostat (aka: defrost termination switch). The defrost timer
DIVERTS power from the thermostat to the defrost heater for about 20
minutes once every 20 hours or so. That means that when the defrost
timer is in defrost mode, power won't be going to the thermostat, and
hence not the compressor and evaporator fan either. So, when the fridge
is in defrost mode, you should NOT hear the compressor running nor feel
a breeze in the freezer compartment. When the defrost cycle is over,
then BOTH the compressor and evaporator fan will always come on and go
off simultaneously. So, if you hear the compressor running, but there's
no breeze in the freezer compartment, there's something wrong with the
evaporator fan. Similarily, if you feel a breeze in the freezer
compartment, but you can't hear the compressor running, there's
something wrong with the compressor.
If the fridge appears to be spending too much time in defrost mode,
it could be that the defrost timer is stuck in defrost mode. Defrost
timers will be equipped with an exposed output shaft that can be turned
to advance the timer manually, putting the fridge back into "run" mode.
That shaft will be designed so that it can only be turned in one
direction with a slot screw driver. That's because turning that shaft
backward can wreck the defrost timer. Unfortunately, the defrost timer
will be located in different places on each fridge, so you have to know
where yours is before you can turn that output shaft and advance the
timer to get the fridge out of defrost mode.
I don't like the thought of an electronic, and some don't have battery. If
power goes off, not sure what happens. I use mechanical like that. Rigging
it up, it's easy to push in on the buttons, but once plugged in, it's easy
to set up. Just make sure it handles compressor currents ok.
I got a dehumidifier running in 2/2 hour mode, but that's a built in
feature of the dehumidifier. It would run continuously otherwise, even set
at 70%. .
My good VCR, that cost $500 30 years ago, had a "memory capacitor", a
little bigger than a nickel, that remembered everything for a long
time. They sell them separately, for less than $5, that I would
have happily paid, at least they used to, but I'm not clever enough to
know where in the circuit to install one. (Maybe some circuits would
drain the cap so fast it wouldn't be useful?)
But my friend's $100 VCR would forget everything in a power failure
and even my $300 Philips or Magnavox DVDR will forget which shows I
want to record, although it remembers which channels there are in my
channel list (I wish it were the other way around.)
A well-made mechanical timer, meaning its motor spins around rather than go
es back and forth (escapement). Some awful timers have motors that do the
latter, like one sold by Harbor Freight, and they don't seem to be reliable
Whatever you get, be sure it's actually safety approved by UL, CSA, TUV, or
ETL, to protect you against electric shock and fire (you don't want plasti
c that burns). And verify that the safety approval is for real because som
e are not, like the one for a Wet Circuits brand power strips (UL issued a
press release about that).
for anyone that has trouble with key equiptement loosing its current time or recordings.
like a DVR, put it on a ups, uninterruptible powqer supply.......
i had mt dish network receivers on UPS because a short power bump got it up to 12 minutes to recover. the 721 model was junk.....
later dish replaced them all;0
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