Looking for120vac thermostat and relay

[amdx]

I'm putting together a circuit to turn on a 120v motor when the temperature
falls to 36*F.

I want a temp sensor that closes at 36*, 3 or 4 degree differential is fine.
It can be adjustable. It must have 120vac rating. Must be able to
waterproof.
I have been buying $60 thermostats that last several years but
there must be something cheaper to do the job.
I also want a relay whose coil will be energized when the thermostat
contacts close. The relay contacts must be able to drive a 1HP motor.
Low cost is a plus.
My undying gratitude will be liberally dispensed.

Thanks, Mikek

 

[amdx]

Swimming pool supply store. My pump controller turns on the pump when
temperatures approach freezing.

...Jim Thompson

Thanks, I'll look into those.
Mikek

 

[amdx]

Thanks, I'll look into those.
Mikek

I looked, they will do the job in one fell swoop, but cost
is to high.
Thanks, Mikek

 

[Ecnerwal]

I want a temp sensor that closes at 36*, 3 or 4 degree differential is fine.
It can be adjustable. It must have 120vac rating. Must be able to
waterproof.
I have been buying $60 thermostats that last several years but
there must be something cheaper to do the job.
I also want a relay whose coil will be energized when the thermostat
contacts close. The relay contacts must be able to drive a 1HP motor.

The more durable (typically) sort of water-sensing thermostats
(aquastats), since you specify "must be able to be waterproofed" have a
capillary and sensing bulb to stick in the water and the rest of it is
located in a dry location. The dry location can be something like a NEMA
exterior rated box if it's more "putting it out in the weather" rather
than "putting it underwater" situation. Attempting to directly
waterproof a thermostat rather than using a rated enclosure would make
your frequent failures non-surprising.

The surplus place I had gotten some nice heavy-duty relays from is now
out of them, too bad. That's surplus. Try to find one rated for MORE
than 1HP at 120 (or rewire the motor application to 240, where it will
be easier to find a relay rated for more than 1HP at 240V) for longer
relay life.

 

[Jamie]

Swimming pool supply store. My pump controller turns on the pump when
temperatures approach freezing.

...Jim Thompson

In Arizona ?

Jamie

 

[Rich Grise]

In Arizona ?

Yes, it's desert, which can get _amazingly_ cold at night. I'm in So. Cal,
and a couple of winters ago I actually saw ice on the sidewalk one morning.
Luckily, being a Minnesot'n, I know how to walk over ice; I saw some
passerby almost fall on his butt, and I almost felt guilty for finding that
so amusing. ;-)

Cheers!
Rich

 

[Rich Grise]

I'm putting together a circuit to turn on a 120v motor when the
temperature falls to 36*F.

I want a temp sensor that closes at 36*, 3 or 4 degree differential is
fine. It can be adjustable. It must have 120vac rating. Must be able to
waterproof.
I have been buying $60 thermostats that last several years but
there must be something cheaper to do the job.
I also want a relay whose coil will be energized when the thermostat
contacts close. The relay contacts must be able to drive a 1HP motor.
Low cost is a plus.
My undying gratitude will be liberally dispensed.

Google Klixon.

Cheers!
Rich

 

[Jeff Layman]

I'm putting together a circuit to turn on a 120v motor when the temperature
falls to 36*F.

I want a temp sensor that closes at 36*, 3 or 4 degree differential is fine.
It can be adjustable. It must have 120vac rating. Must be able to
waterproof.
I have been buying $60 thermostats that last several years but
there must be something cheaper to do the job.
I also want a relay whose coil will be energized when the thermostat
contacts close. The relay contacts must be able to drive a 1HP motor.
Low cost is a plus.
My undying gratitude will be liberally dispensed.

Thanks, Mikek

When I needed a fail-safe thermostat to keep my greenhouse frost-free, I
used a refrigerator thermostat to operate a relay which switched on a
fan heater. The adjustable control could be mounted in a waterproof
container if necessary, with the copper sensing tube outside. If the
thermostat fails it will usually go open-circuit, cutting off power to
the relay, whose normally-closed contacts then switch on the heating.

FWIW, this system has been operating for nearly 12 years without problem.

 

[amdx]

When I needed a fail-safe thermostat to keep my greenhouse frost-free, I
used a refrigerator thermostat to operate a relay which switched on a fan
heater. The adjustable control could be mounted in a waterproof container
if necessary, with the copper sensing tube outside. If the thermostat
fails it will usually go open-circuit, cutting off power to the relay,
whose normally-closed contacts then switch on the heating.

FWIW, this system has been operating for nearly 12 years without problem.

Jeff

That's basically what I'm doing. I'm using this thermostat,
http://www.grainger.com/Grainger/ww...E399&op=search&Ntt=2E399|2E399&N=0&sst=subset
and drive a relay that turns on a water pump. I use the heat in the water
to keep my greenhouse from freezing.
I put the thermostat in a pvc pail with a lid and the bulb slips through a
hole.
The thermostat never gets wet or even damp, but I'm on my fourth in 15
years.
I was looking for a cheaper setup to make for my nephew.
So far nothing the only thing I have found is the swimming pool freeze
protection thermostat
at $32 with free shipping.
Mikek

 

[ehsjr]

I'm putting together a circuit to turn on a 120v motor when the temperature
falls to 36*F.

I want a temp sensor that closes at 36*, 3 or 4 degree differential is fine.
It can be adjustable. It must have 120vac rating. Must be able to
waterproof.
I have been buying $60 thermostats that last several years but
there must be something cheaper to do the job.
I also want a relay whose coil will be energized when the thermostat
contacts close. The relay contacts must be able to drive a 1HP motor.
Low cost is a plus.
My undying gratitude will be liberally dispensed.

Thanks, Mikek

http://www.fosterandsmithaquatics.com/product/prod_display.cfm?pcatid=5507

That is a thermostatically controlled 15 amp outlet.
Turns on at ~35 degrees F, and off at ~45 degrees.
$12.95

Ed

 

[amdx]

http://www.fosterandsmithaquatics.com/product/prod_display.cfm?pcatid=5507

That is a thermostatically controlled 15 amp outlet.
Turns on at ~35 degrees F, and off at ~45 degrees.
$12.95

Ed

That is very close, The differential is to much.
I may but one just to see if I could modify it.
Thanks, Mikek

 

[Jeff Layman]

That's basically what I'm doing. I'm using this thermostat,
http://www.grainger.com/Grainger/ww...E399&op=search&Ntt=2E399|2E399&N=0&sst=subset
and drive a relay that turns on a water pump. I use the heat in the water
to keep my greenhouse from freezing.
I put the thermostat in a pvc pail with a lid and the bulb slips through a
hole.
The thermostat never gets wet or even damp, but I'm on my fourth in 15
years.
I was looking for a cheaper setup to make for my nephew.
So far nothing the only thing I have found is the swimming pool freeze
protection thermostat
at $32 with free shipping.
Mikek

I thought spares were cheaper in the US than here in the UK! See here
(£1.00 ~ $1.63):
http://www.easyspares.co.uk/products.asp?c=62&c2=144

May be worth the shipping cost...