24V LED Indicator Light Question?

[marty]

See these LED Indicator Lights at West Marine

http://www.bluesea.com/products/8171/LED_Red
LED Red
PN 8171
Nominal Voltage - 12V DC / 24V DC
Circuit - Resistor
Current - 3mA @ 12V / 6mA @ 24V
Power Consumption 19mW @ 12V / 75mW @ 24V
Wire Gauge 26

Would these work with 24V AC in HVAC stuff?
HVAC = Heating, Ventilation, + Air Conditioning

 

[yopappamon]

Maybe. Depends on if the LED can take 24v reverse voltage.

AC means the polarity switches 60(50) times per second. When the polarity is correct (plus to plus, negative to negative) the led will light correctly. When the polarity is reversed ( plus to negative, negative to plus) you reverse bias the diode ( led). There is a reverse voltage rating for the led. If it is greater than 24v then no problem. If not, poof! Smokey smokey.

You could put a cheap diode in series with the indicator to prevent the reverse voltage from reaching the led. Then I think it would work.

 

[dumbass]

Most HAVC systems use a 24v DC transformer. Therefore, the LEDs should work however, you need to verify that the transformer is 24v and DC. Most setups will also have extra capacity that would handle the added load of the LEDs. But again it would be wise to verify the current load and the transformer's capacity.

Bob

 

[marty]

Most HAVC systems use a 24v DC transformer. Therefore, the LEDs should work however, you need to verify that the transformer is 24v and DC. Most setups will also have extra capacity that would handle the added load of the LEDs. But again it would be wise to verify the current load and the transformer's capacity.

Bob

Think you are wrong. All the HVAC systems that I have played with were 24V AC.
120V AC goes into transformer, 24V AC comes out.

 

[dumbass]

Looks like we are both correct ( you more then I) but the units I've had were 24vdc. However, based on the articals I've found indicate most HVAC do use 24vac especially in the older models. In any case as I pointed out originally you should verify what YOUR trasformer is (AC, DC and voltage). It should be written on the trasformer or you can verify it with your ac/dc volt meter. And depending on how many of these LEDs you are planning to use you should check that the trasformer has the extra capasity which it likely has.

Bob

 

[marty]

Buy it. Try it. It works!

There is something under the shrink wrap on the yellow wire. I am guessing a diode or resistor?

 

[dumbass]

Glad it works for you but what are you using them for? Bob

 

[marty]

Glad it works for you but what are you using them for? Bob

Enthalpy Controller, Economizer

Switching Action:
Single pole double throw (spdt)

Will have 2 LEDs to show good air or bad air when thermostat calls for cooling.

 

[marty]

Got the thermostat project finished
Anyone looking for a expensive thermostat with all the bells and whistles. I recommend Honeywell Prestige. Play with it by touching the screen. No buttons.

Get a outdoor sensor and it will tell you the outdoor temperature. I did not get a humidity sensor. Only get the wireless ones if you like to replace batteries. I ran 18-2 to the outdoor temperature sensor. Go here instructions on how to fish wires.

This thermostat works with a box in the basement called EIM Equipment Interface Module. I mounted the LEDs next to the EIM so the homeowner can spend hours watching the heating, cooling, and LEDs go off and on. EIM has more LEDs on the inside. Cut a little hole in the cover so we can all watch Red and Green LEDs.

Thermostat communicates with EIM through the air. Two wires make it light up. DO NOT mount it next to the EIM like I did for testing. It was freaking out. Tech guy at Honeywell thought it was "learning". It was not learning. It developed a serious learning disability. Moved it 4 feet away and all is good. Will put it upstairs as soon as the painters are done. Don't ya hate it when the painters get paint on a nice new thermostat?