DIY Electrical question

[Lawrence]

Hoping someone out there can help an 'electrically challenged'
do-it-yourselfer. Electricity and I don't get along but I'm very
handy. I can solder, weld, woodwork ..... I just don't understand
electrical things well.

Here is what I'm looking for;

I am running four 120 volt a.c. fans
(http://www.allelectronics.com/cgi-bin/category.cgi?category=220200&item=CF-174&type=store)two
in my hood and two in my base cabinet for the refugium. Each fan plugs
straight into timers that are set with my light cycles to keep things
cool but this isn't working out. What I would really like to do is
have them come on/off when the temperature in the hood or the cabinet
climbs over a set temperature and goes off again once it's cooled
below a set temperature.

Does anyone have simple plans to make such temperature sensors that I
can operate with the 120 volt a.c. fans. I considered a thermostat
like you have in your home for the furnace and air conditioning units
but these are 24 volts a.c. and being 'electrically challenged' makes
that conversion tough without a 'connect the dots' plan. I'm hoping
someone out there has an easy solution.

Thanks
Lawrence

[Mark A. Odell]

(Lawrence) wrote in
m:

> Here is what I'm looking for;
>
> I am running four 120 volt a.c. fans
> (http://www.allelectronics.com/cgi-bin/category.cgi?category=220200&item=
> CF-174&type=store)two in my hood and two in my base cabinet for the
> refugium. Each fan plugs straight into timers that are set with my light
> cycles to keep things cool but this isn't working out. What I would
> really like to do is have them come on/off when the temperature in the
> hood or the cabinet climbs over a set temperature and goes off again
> once it's cooled below a set temperature.
>
> Does anyone have simple plans to make such temperature sensors that I
> can operate with the 120 volt a.c. fans. I considered a thermostat
> like you have in your home for the furnace and air conditioning units
> but these are 24 volts a.c. and being 'electrically challenged' makes
> that conversion tough without a 'connect the dots' plan. I'm hoping
> someone out there has an easy solution.

Have the home thermostat run off a wall-wart supplying 24VDC. By a 120VAC
power relay that is controlled by a DC signal - connect the thermostat to
the power relay.

--
- Mark ->
--

[Chris Gentry]

I really don't know how safe this is, but my dad used to have a large number
of greenhouses, and he wired a home thermostat directly inline with the
blower motor, which was 120v ac. It worked great for years.

"Lawrence" > wrote in message
m...
> Hoping someone out there can help an 'electrically challenged'
> do-it-yourselfer. Electricity and I don't get along but I'm very
> handy. I can solder, weld, woodwork ..... I just don't understand
> electrical things well.
>
> Here is what I'm looking for;
>
> I am running four 120 volt a.c. fans
>
(http://www.allelectronics.com/cgi-bin/category.cgi?category=220200&item=CF-
174&type=store)two
> in my hood and two in my base cabinet for the refugium. Each fan plugs
> straight into timers that are set with my light cycles to keep things
> cool but this isn't working out. What I would really like to do is
> have them come on/off when the temperature in the hood or the cabinet
> climbs over a set temperature and goes off again once it's cooled
> below a set temperature.
>
> Does anyone have simple plans to make such temperature sensors that I
> can operate with the 120 volt a.c. fans. I considered a thermostat
> like you have in your home for the furnace and air conditioning units
> but these are 24 volts a.c. and being 'electrically challenged' makes
> that conversion tough without a 'connect the dots' plan. I'm hoping
> someone out there has an easy solution.
>
> Thanks
> Lawrence

[Gary V. Deutschmann, Sr.]

Hi Larry

They make plug in thermostats with 120 volt electrical taps on them
already and a remote sensor to put into your hood. Ingram is one
company, I'm sure there are several others.

If you want to construct your own using a low voltage thermostat, the
only other component you will need would be a relay for 120 volts
switching with a 12 or 24 volt coil, depending upon your transformer
size. Most furnace transformers are 24 volts AC output, so your Relay
should have a coil for 24 volts AC. Add up the current each of your
fans pulls and make sure the Contacts of the relay are rated for that
amount of current passing through them. If a relay is too small, the
current will weld the contacts together and ruin the relay.

The cheapest way you could possibly go to accomplish what you are
after is by using an adjustible bi-metallic contact set rated for 120
volts, the 15 amp size is common and fairly low in cost. These are
found inside of mechanical thermostats, but not normally designed to
carry more than 1/4 amp if that. Price depends upon where you find
them. I have seen them from 89 cents all the way up to 15 bucks for
the same identical component, so shop wisely.

TTUL
Gary

[Ken N]

You may want to check out these fans I used. They are super quiet and have a
built in thermostat that varies their speed to the heat. Only draw back is
they are 12vdc but could be run from a small wallpack transformer plugged
into one of your timers to come on with the lights.
http://www.silenx.com/productcart/pc/configurePrdz.asp?idcategory=3&idproduct=9
I use two to blow in from the back across my MH's and two to exhaust out the
top of my hood.
Just an idea

Ken


"Gary V. Deutschmann, Sr." > wrote in message
...
> Hi Larry
>
> They make plug in thermostats with 120 volt electrical taps on them
> already and a remote sensor to put into your hood. Ingram is one
> company, I'm sure there are several others.
>
> If you want to construct your own using a low voltage thermostat, the
> only other component you will need would be a relay for 120 volts
> switching with a 12 or 24 volt coil, depending upon your transformer
> size. Most furnace transformers are 24 volts AC output, so your Relay
> should have a coil for 24 volts AC. Add up the current each of your
> fans pulls and make sure the Contacts of the relay are rated for that
> amount of current passing through them. If a relay is too small, the
> current will weld the contacts together and ruin the relay.
>
> The cheapest way you could possibly go to accomplish what you are
> after is by using an adjustible bi-metallic contact set rated for 120
> volts, the 15 amp size is common and fairly low in cost. These are
> found inside of mechanical thermostats, but not normally designed to
> carry more than 1/4 amp if that. Price depends upon where you find
> them. I have seen them from 89 cents all the way up to 15 bucks for
> the same identical component, so shop wisely.
>
> TTUL
> Gary
>

[Lawrence]

Thanks Mark, Chris, Gary and Ken ... Ken I've followed up with your
suggestion on the Silenx 80mm Thermistor Fan. Matt at Silenx was
helpful answering some of my questions. Here's some of the questions I
got answered.

What temp range do these fans operate in? These fans run continuously
at 1200 rpm but when the temp rises above 80F they jump to 2400 rpm.
The 14dBa claim is at the 2400 rpm speed.

How do I power them? A 12vdc wall-wart from radio shack will do it.
Need at least 420 mA for each fan. Therefore radio shacks 1000 mA
model (#273-1776) can power two fans.

Question for you Ken, seeing as you operate these fans ..... I intend
to have both fans pushing/blowing air into the hood from either end
(back of the hood is open). How well do the Silenx fans drawing air
into your hood pickup the temp inside the hood? That's a tough
question to pose, what I'm wondering is ... if the fan is drawing
outside air across itself (thus keeping the heat sensor on the fan
cool), don't those two just operate at the lower speed all the time?

Lawrence

"Ken N" > wrote in message news:<xCb6c.33395$1p.529402@attbi_s54>...
> You may want to check out these fans I used. They are super quiet and have a
> built in thermostat that varies their speed to the heat. Only draw back is
> they are 12vdc but could be run from a small wallpack transformer plugged
> into one of your timers to come on with the lights.
> http://www.silenx.com/productcart/pc/configurePrdz.asp?idcategory=3&idproduct=9
> I use two to blow in from the back across my MH's and two to exhaust out the
> top of my hood.
> Just an idea
>
> Ken
>
>
> "Gary V. Deutschmann, Sr." > wrote in message
> ...
> > Hi Larry
> >
> > They make plug in thermostats with 120 volt electrical taps on them
> > already and a remote sensor to put into your hood. Ingram is one
> > company, I'm sure there are several others.
> >
> > If you want to construct your own using a low voltage thermostat, the
> > only other component you will need would be a relay for 120 volts
> > switching with a 12 or 24 volt coil, depending upon your transformer
> > size. Most furnace transformers are 24 volts AC output, so your Relay
> > should have a coil for 24 volts AC. Add up the current each of your
> > fans pulls and make sure the Contacts of the relay are rated for that
> > amount of current passing through them. If a relay is too small, the
> > current will weld the contacts together and ruin the relay.
> >
> > The cheapest way you could possibly go to accomplish what you are
> > after is by using an adjustible bi-metallic contact set rated for 120
> > volts, the 15 amp size is common and fairly low in cost. These are
> > found inside of mechanical thermostats, but not normally designed to
> > carry more than 1/4 amp if that. Price depends upon where you find
> > them. I have seen them from 89 cents all the way up to 15 bucks for
> > the same identical component, so shop wisely.
> >
> > TTUL
> > Gary
> >

[Ken N]

The temp sensor is located at the end of a 8-10" wire, so it can be mounted
anywhere around the fan. Like I said I have one mounted directly behind each
of my two metal halides to blow over them. I mounted the temp sensor near
the reflector of each halide. I also was thinking of using all four to blow
into the hood, but I found that using two to pull the hot air out of the top
of the hood worked really well. Here is a pic of my hood during
construction (https://home.comcast.net/~kensn/images/hood2.jpg). If you look
you can see the two fans behind the lights. The other two that were mounted
in the top of the hood were not installed yet. They were put in the top
corners in front of the lights. You can really feel the warm air coming from
the two that are mounted in the top. If you have any other questions please
feel free to ask.

Ken N.


"Lawrence" > wrote in message
om...
> Thanks Mark, Chris, Gary and Ken ... Ken I've followed up with your
> suggestion on the Silenx 80mm Thermistor Fan. Matt at Silenx was
> helpful answering some of my questions. Here's some of the questions I
> got answered.
>
> What temp range do these fans operate in? These fans run continuously
> at 1200 rpm but when the temp rises above 80F they jump to 2400 rpm.
> The 14dBa claim is at the 2400 rpm speed.
>
> How do I power them? A 12vdc wall-wart from radio shack will do it.
> Need at least 420 mA for each fan. Therefore radio shacks 1000 mA
> model (#273-1776) can power two fans.
>
> Question for you Ken, seeing as you operate these fans ..... I intend
> to have both fans pushing/blowing air into the hood from either end
> (back of the hood is open). How well do the Silenx fans drawing air
> into your hood pickup the temp inside the hood? That's a tough
> question to pose, what I'm wondering is ... if the fan is drawing
> outside air across itself (thus keeping the heat sensor on the fan
> cool), don't those two just operate at the lower speed all the time?
>
> Lawrence
>
> "Ken N" > wrote in message
news:<xCb6c.33395$1p.529402@attbi_s54>...
> > You may want to check out these fans I used. They are super quiet and
have a
> > built in thermostat that varies their speed to the heat. Only draw back
is
> > they are 12vdc but could be run from a small wallpack transformer
plugged
> > into one of your timers to come on with the lights.
> >
http://www.silenx.com/productcart/pc/configurePrdz.asp?idcategory=3&idproduct=9
> > I use two to blow in from the back across my MH's and two to exhaust out
the
> > top of my hood.
> > Just an idea
> >
> > Ken
> >
> >
> > "Gary V. Deutschmann, Sr." > wrote in
message
> > ...
> > > Hi Larry
> > >
> > > They make plug in thermostats with 120 volt electrical taps on them
> > > already and a remote sensor to put into your hood. Ingram is one
> > > company, I'm sure there are several others.
> > >
> > > If you want to construct your own using a low voltage thermostat, the
> > > only other component you will need would be a relay for 120 volts
> > > switching with a 12 or 24 volt coil, depending upon your transformer
> > > size. Most furnace transformers are 24 volts AC output, so your Relay
> > > should have a coil for 24 volts AC. Add up the current each of your
> > > fans pulls and make sure the Contacts of the relay are rated for that
> > > amount of current passing through them. If a relay is too small, the
> > > current will weld the contacts together and ruin the relay.
> > >
> > > The cheapest way you could possibly go to accomplish what you are
> > > after is by using an adjustible bi-metallic contact set rated for 120
> > > volts, the 15 amp size is common and fairly low in cost. These are
> > > found inside of mechanical thermostats, but not normally designed to
> > > carry more than 1/4 amp if that. Price depends upon where you find
> > > them. I have seen them from 89 cents all the way up to 15 bucks for
> > > the same identical component, so shop wisely.
> > >
> > > TTUL
> > > Gary
> > >

[Ross Bagley]

"Ken N" > writes:

> I use two to blow in from the back across my MH's and two to exhaust out the
> top of my hood.

Don't bother to install the two exhaust fans. Put the holes in place,
but fill the holes with a louver or grating instead of a fan. If you
already have them, keep the two extra fans for spares.

The "big problem" with exhaust fans on marine tanks is that the air
inside your hood is laden with salt water and is extremely corrosive
to metal (including the copper wiring in the motor core inside the
fan). Any unsealed exhaust fan will fail within a month or two from
this aggressively corrosive environment.

You'll get almost as much airflow from the empty holes as you would
with the fans in place (80%+). The intake fans will drive a nice
positive pressure that will keep the air flowing in exactly the same
direction, but without the salt air being pulled across the fan
components.

This suggestion does assume that the location of the intake fans is
low humidity. If not, you're going to have the same problem (motor
corrosion) until you run a duct from a low humidity area to the
intake openings.

Regards,
Ross

-- Ross Bagley http://rossbagley.com/rba
"Security is mostly a superstition. It does not exist in nature...
Life is either a daring adventure or nothing." -- Helen Keller

[Gary V. Deutschmann, Sr.]

Hi Ross

I won't argue with your logic as it is quite feasible!

But on the other side of the coin, I have two square muffin fans, like
found in power supplies, both had run for almost 10 years with no
problem pulling air not pushing it from the lighting on my reef
aquarium. Yes they have both changed from black to white over the
years as salt built up on them, but at $7.00 each back then, probably
$9 to $14 today, my cost of replacements has been nil.

The ONLY problem I have had is they go out of balance from salt
buildup and need to be washed occasionally.
It could be their design as to why they last so long, the center hub
of the spinning blades covers the entire motor and the inside of this
hub has remained black has the front of the motor housing itself.
I do also oil the bearings with a TufOil Lub-It pen, each time I clean
them.

TTUL
Gary

[Ross Bagley]

(Gary V. Deutschmann, Sr.) writes:

> Hi Ross
>
> I won't argue with your logic as it is quite feasible!
>
> But on the other side of the coin, I have two square muffin fans, like
> found in power supplies, both had run for almost 10 years with no
> problem pulling air not pushing it from the lighting on my reef
> aquarium. Yes they have both changed from black to white over the
> years as salt built up on them, but at $7.00 each back then, probably
> $9 to $14 today, my cost of replacements has been nil.

I suppose that it would depend on the design of the actual fan
in question.

I appear to have bad luck in that department, but found that only
using intake fans seemed to cause no reduction of ventilation and
a substantially smaller pile of ruined fans.

Regards,
Ross

-- Ross Bagley http://rossbagley.com/rba
"Security is mostly a superstition. It does not exist in nature...
Life is either a daring adventure or nothing." -- Helen Keller