Anyone see a problem with this?

[shockhazard]

Or know of a better way?

A ceiling hung, gas unit heater cycles very frequently because of how fast the garage loses heat.

495

Thanks, any help is appreciated.

[ctrlguy]

How about this?
498

[rango]

I'm no controls guy and wondering if you can explain the components of the drawing and how it prevents frequent cycling. Thanks,

rango

[codewriter]

Whats the logic on the first post? Why the cooling stat, like that it serves no purpose for the application.

The second one really makes no sense to me either, could be done without the relay.

But what has me most confused, is why two stats on a single heater?
Unless maybe the stats are in different area's, but why the setpoint differance?

Maybe give an example of what your trying to accomplish.

[glennwith2ns]

ah, why not get a stat with an adjustable differential and forget all that extra stuff?

[codewriter]

ah, thanks to glenn I now see what your trying to do.
I'm a bit slow with simple logic... hahaha

The second post will do exactly what your looking for. That is, if your looking for it to enable when the temp drops below 45, the disable when the temp rises above 60.

[simsd]

If it's that cold, why bother with the high limit?

Second if it cycles then I see one or two scenarios. If it's cold, then it's cold. The heat loss through the doors and walls contributes to this. Second, is it a thermostat placement issue?

[shockhazard]

Thanks ctrlguy, that'll save me a relay and keep things simpler.

It's a garage, I'm not looking to heat it as living space, just want to keep from freezing the jewels off while working out there. The unit will heat +15° in minutes, and the space will hold for 30/45 minutes. I'd prefer the unit run once an hour or so, rather then every 10 minutes, more of an annoyance than anything. Right now I'm doing it manually with a trip to the tstat every cycle. I haven't found a tstat with a 15° swing, and I already have 2 tstats (free leftovers from a job) and an assortment of control relays.

Thanks for the help.

[PrestonPierce]

How about this?
498


This works

[PrestonPierce]

Cntrol guy 's works

[PrestonPierce]

Ok , a little easier this way, Edit: just use the other one

[mdharris68]

What about just hooking to a voice activated remote control?:D Or one of the "As seen on TV" clappers; clap on clap off:D

[johnl]

Preston i dont see how that is going to work. The only way you are powering W is in series with the relay coil. Even if you moved the relay coil to the other side of W, it would lock the unit on as soon as the R1 relay was powered.
How about using an A419 thermostat and setting the differential at 15 degrees?

[PrestonPierce]

Made an edit,

[PrestonPierce]

Preston i dont see how that is going to work. The only way you are powering W is in series with the relay coil. Even if you moved the relay coil to the other side of W, it would lock the unit on as soon as the R1 relay was powered.
How about using an A419 thermostat and setting the differential at 15 degrees?

It latches it on when you drop below 45, then unlatches above 65, take another look I did need to edit it, sorry. Had the edits in visio and forgot to save them.

[johnl]

That makes more sense now.
Still easier to use an A419 digital stat and set the diff at 15 lol

[PrestonPierce]

I didn't show a common

[PrestonPierce]

That makes more sense now.
Still easier to use an A419 digital stat and set the diff at 15 lol

Yeah but this a lot more fun,,

[jayhawker]

What type of burner does the unit use, could you use a Maxitrol system to modulate the gas input to match the heat loss, a outdoor air t-stat to lock the furnace out and an indoor thermostat with a adjustable diff. as the low and high limit.

[PrestonPierce]

Sounds like a no frills on/off burner control. Otherwise he may have had a different control on the wall.

[PrestonPierce]

With the original pictorial drawing,

[codewriter]

This doesn't work, it will turn the furnace off when it goes abover 45, it is not what he is looking for,


Should run the stats in series using the Y terminal like he already has,

How do you figure it will turn off when it goes above 45? Since the NO is closed once the temp drops below 45, the 60 degree stat will maintain power at the coil which will keep the NO closed until the temp rises above 60.

[PrestonPierce]

I'm no controls guy and wondering if you can explain the components of the drawing and how it prevents frequent cycling. Thanks,

rango

Rango,

The idea is to have a wide differential that you can't get with one mechanical stat,

[PrestonPierce]

How do you figure it will turn off when it goes above 45? Since the NO is closed once the temp drops below 45, the 60 degree stat will maintain power at the coil which will keep the NO closed until the temp rises above 60.

I guess that does work,

[simsd]

This is hilarious guys. 25 threads all for this?

[PrestonPierce]

LOL, I missed cntrol guy's jumper, and he saves a relay, thats the way to go.

[crab master]

Why not just use a refrigeration thermostat? If the action cannot be reversed to close on a drop and open on rise then add a spdt relay to get the action needed.
Also you can get that wide of a differential with a mechanical stat, but it will have to be a refrigeration type stat, not a standard heat/cool stat.
Ranco
Commercial Electronic Temperature Controls
• Digital display allows for simple and accurate setting
• Displays sensor temperature when not in program mode
• Wide temperature range (-30°F to +220°F) and differential adjustment (1°F to 30°F)
• User selectable heating/cooling modes for wide application use
• Capable of remote temperature sensing up to 400'
• Keypad lockout switch to prevent tampering
• Replaces most electromechanical and electronic temperature controls
Specifications:
• Switch action: SPDT
• Includes thermistor sensor, 2" x 0.25" with 8' cable
• Relay output rating: N.O. contact 16A @ 120VAC, N.C. contact 5.8A @ 120VAC
• Dimensions: 6.52" H x 2.7" W x 2.48" D


Johnstone Supply Part #'s
Select a Product to Inquire - Log In to Enter Order Mode.
Order # Mfg. # Input Voltage Stages Enclosure Rating
L38-383 ETC112000 24 1 NEMA 1
L38-382 ETC111000 120/240 1 NEMA 1
L38-385 ETC141000 120/208/240 1 NEMA 4X
L38-714 ETC211000 120/240 2 NEMA 1
L38-715 ETC212000 24 2 NEMA 1
L38-386 ETC241000 120/208/240 2 NEMA 4X

[simsd]

How come nobody has suggested and allen bradley plc contrologix with a colour tough screen? :)

[MoontwpChad]

How would you setback with a clapper?

[shifferbrains]

It sounds like your heater is oversized. Why not just use a time delay relay on the heating circuit. They cost about twenty dollars at Jonstone Supply. then your thermostat can call for heating and you can adjust the time delay to what ever you need. Be sure it's an ON Delay and not an OFF Delay.

[simsd]

Are we still on this?

It will be summer soon.