2477SA2 Load Controller - What the heck do the lights mean?

[chrishick]

The documentation is a little confusing. There are 2 lights on the front of the controller, 1 shows relay status, green for closed(or on) and off for open(or off). That much makes sense.

 

But then there is another light for "Load Active". Sometimes this light stays green even though the relay is open and the controller is off. This is counter intuitive, how can the load be active when the relay is open?

 

I'm sure someone smarter than me understands what is going on here?

 

Thanks,

 

Chris 

[stusviews]

Do you have the NO or NC controller?

[chrishick]

It is NC.

[stusviews]

Apparently, the load has power even when the relay is open. You may want to double check the wiring. Is there a neutral wire involved at all?

[mwester]

...

 

But then there is another light for "Load Active". Sometimes this light stays green even though the relay is open and the controller is off. This is counter intuitive, how can the load be active when the relay is open?

 

...

 

The relay in that device is rather small considering the general type of load that would justify its use (more specifically, something running at 240VAC in North America is set up to run at that voltage in order to cut the amperage in half compared to running at 120VAC... something a manufacturer will typically only do if the device consumes huge amounts of power).

 

My point is that (assuming the unit is wired correctly) if the load light does not change despite switching states, that rather small relay may have the contacts welded closed.  That's a potentially-dangerous situation, so were I you, I'd check with a voltmeter to make sure it's operating as it should.

 

For high-current loads, a better solution than the 2477SA is to simply use a micro on/off unit driving a 120VAC "Definite Purpose Contactor" -- this type of contactor is a low cost, common as dirt (well, almost), unit used in almost every HVAC unit to switch the 240VAC to the compressor pump.   (The Packard C230B unit can switch 240VAC at 30A, and can be obtained new for under $10 for example.) You'll need your own electrical box to house it, but that's pretty easy to do.

[chrishick]

No, it is definitely working correctly and it cycles the water heater on and off as it should. This is from the owners manual. The only thing I can figure is that "closed with load off" means the relay is closed but the load is drawing 0 amps. I'm not sure why they even thought we needed a light to tell us that.

 

Here's the thing though, I've seen the load active light on when the relay is open, which isn't a condition listed in the owners manual.

 

I'm not really that worried about it, as I said it is working as needed, I just thought somebody might know what the load active light meant.

 

 

 

 

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[chrishick]

Also, when the load active light is lit even though the relay is open, the load is truly off and the relay is in the open position. It is operating as it should.

 

 

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