I just purchased a brand new hot plate with magnetic stirring and all.
Hooray.
No instruction manual.
Anyway, I tested it out to distill water and Etoh for funsies and I had a stainless steel bowl on top with peanut oil and its one of those hot plates
with the probe temperature controls. I set the desired temperature to 100 and all went well til it stopped dead at 84. Oh well heating curves are
supposed to do that. Well, 12 hrs later when it was still 84, I knew there was a problem. It wouldn't get regular ass water past 83 degrees either
So
Am I missing something?
Do bathroom outlets have less voltage?
Am I just being impatient?
Has anyone had experience with the "probe" temp controllers (the ones that have no heat knob - just a digital temperature to "set")
Is there anyway I cam just say screw the probe and use its full power? When I unplug the probe it goes haywire.
Thanks in advance friendsNeil - 16-10-2011 at 12:56
make? model? Amy Winehouse - 16-10-2011 at 13:23
Right.
XMTD-701
85-2 Magnetic Stirrer
NUOHAI
I purchased it from chang bioscience. Amy Winehouse - 16-10-2011 at 13:35
It is under 300watts but above 250, indoors that should be plenty hot. (every description of the same product is different....)
Your average hair drier pulls twice the max wattage of your hotplate so if the outlet runs a hair drier...
Does the voltage it is set to run on correspond to your household voltage? ie is it set to 120V and are you on 120V?
Have you tried contacting the seller for the manual?
How hot does it get when the temperature probe is left out of the heating bath?
Amy Winehouse - 16-10-2011 at 16:14
Yeah thats what i thought, about the hair drier.
I have contacted the seller and the parent company.
I'm not really sure about the voltage of my house, the specs of the stirrer say they that it is 110V. Im kind of a noob when it comes to electricity
And yeah, I put the temperature probe into a glass of ice water thinking i was clever as hell and my mercury thermometer read me the bad news that it
didnt change one degree past 84
I DID find an internal menu where i am allowed to change the value of the following parameters:
AL(Which i assume to be the alarm [there is a timer])
HY (No clue)
P(no clue [power?])
I (no clue)
d(nope)
backwards 7 (looks like a weird r)
and...
LCY (also no clue)
Are these universal parameters? Do any involve setting the voltage to my house? Do i need a manometer?
Thanks for your help dude I appreciate it!
fledarmus - 16-10-2011 at 17:14
i know the heater-stirrers I use at work have two sets of heat controls - one determines the maximum heat of the plate, the other determines the
maximum heat for the probe. I suspect that one of those parameters you listed is the maximum heat of the plate, and it just isn't heating high enough
that the probe can shut off the temperature.
This means that you can set the plate temperature to be 150C, for example, then have your probe in the liquid set to 100C. That will allow you to
reach the boiling point of water without burning the bowl your water is in.
This also means that you could accidentally have the hot plate set to 90C and be trying to heat your solvent up to 100C. It won't ever get high enough
that the probe shuts off the heat.
Shouldn't have anything to do with your house current or the pressure (no manometer).
Not sure what the letters mean - I'll check mine when I get in to work and see what they are labeled. Frankly, I set all the temps on the plate when I
got it and haven't changed them since.
[Edited on 17-10-2011 by fledarmus]Amy Winehouse - 16-10-2011 at 21:00
Sweet man that makes a lot of sense! The two paragraphs of direction that DID come with it were poorly - VERY - poorly translated from chinese.
Quote:
"press SET key to set temperature. After pressing SET key, data on lower line digital tube will flash (the upper low measure temperature normally),
which means meter enters the status of temperature setting. Press up key to increase set value, and press down key to decrease set value. [no way] If
continuously press increase key or decrease key, set value will change rapidly. Press SET key again, and meter returns to temperature under normal
working status. Setting is finished."
Amy Winehouse - 18-10-2011 at 19:07
Okay, so i returned the stupid hot plate.
Chapter 2: Amy Winehouse's problems with hot plate
So I bought a hotplate that has an ON/OFF controller, because i wanted the simplicity. But in hindsight, I might have just done that irrationally out
of frustration because i do want SOME temperature control. Are there any techniques/ways to control the temperature of an ON/OFF controller?ldanielrosa - 19-10-2011 at 01:41
< ramble>
I'm sorry to hear you're having these issues. I had fantasized about having these features, and this even delayed my purchase. Being an electronics
hobbyist with interest in microcontrollers, I had given some thought to what I _could_ build- but I figured out I wasn't gonna make it soon enough, so
I bought one of the primitive types.
Anyways, for some things I don't want to risk the beautiful dinosaur so I also went to freddy's and bought a kitchen hotplate ($14) for the corrosive
stuff I only do outside. No stir capability, but plenty of heat.
< /ramble>
[Edited on 19-10-2011 by ldanielrosa]watson.fawkes - 19-10-2011 at 04:32
But in hindsight, I might have just done that irrationally out of frustration because i do want SOME temperature control. Are there any
techniques/ways to control the temperature of an ON/OFF controller?
Use the unit that's behind the dial in
most electric stoves. It has a little heater and bimetallic strip in it. It will give up a pulse train at a variable duty cycle. Keep them enough
separated from the heater so that their setting doesn't drift during use.
You can buy them as replacement parts, worse come to worst. But any place that does appliance repair or refurbishment tends to have boxes and boxes
full of them. They pull them off units headed for the metal scrapper. The folks in those shops understand tinkerers, because they are tinkers
themselves. They'll sell you a few for cheap and might even give you a few for free if your story is good.Amy Winehouse - 19-10-2011 at 14:23
I understand the concept, but how does the simmerstat connect with the hot plate? Siloxane - 20-10-2011 at 20:09
For quick n' dirty, just wire the heating element of the hot plate across the load side of the simmerstat. Cut the wall plug off of the hot plate; if
it's a regular two prong plug, hook the two wires up to the line side of the 'stat.
Note: you can get a really, really cheap simmerstat if you go to your local thrift store. Pick up a deep fryer or griddle with a control knob on it,
the kind that pulls out. Just pull the simmerstat out and wire the heating element of your hot plate to the part that resembles an oversized
headphone plug. YMMV.watson.fawkes - 21-10-2011 at 02:53
I understand the concept, but how does the simmerstat connect with the hot plate?
http://www.electrical-forensics.com/ElectricRanges/ElectricRange.html is a better article. As a bonus, there are plenty of pictures of fire
investigations. There's a wiring diagram on that page. I had never heard them called simmerstats, but that name seems to have some currency. I've more
often heard them called "infinite heat controls", for infinite number of "detents" for setting the heat level.Rogeryermaw - 3-11-2011 at 17:49
through latent heat of vaporization, water loses heat pretty quickly. as the water on your hotplate evaporates, it will carry a lot of heat away with
it. if the plate top is set for 100 degrees, no appreciable quantity of water will reach that temp. you will have to set the plate higher and monitor
the water temp until it stabilizes at the desired temp. also, the purity of the water will be an issue. if you want water that actually boils at
100C, use distilled.
