Water leak detector

Someone named "Sparky" Proclaimed on Mon, 04 Oct

2004 21:25:51 GMT,

Hook one of these :

-Graham

Remove the 'snails' from my email

Someone named G. Morgan Proclaimed on Mon, 04 Oct 2004 16:42:10 -0500,

The WB-200 on that page specifically. It has a form-C relay output you can break the x-former wire of the air handler though for shutdown. (or the red wire from the thermostat circuit)

-Graham

Remove the 'snails' from my email

if the unit iced up then shutting it down will just let the ice melt.

if this is a window unit make sure it is mounted so it angles down to the outside. you can usually drill a couple extra drain holes in the bottom without hurting anything (if done with care).

Decent condensate pumps have two float switches?one to cycle the pump and a second, slightly higher one to kill the condensing-unit contactor.

Verify that there is no negative pressure on the condensate-drain tube causing restricted flow. Some evaporator-drip pans have a second drain at a slightly higher elevation.

Years ago 'popular mechanics' suggested using a basement-floor aspirin tablet under the leaf of a microswith.

?s falke

For a home brew solution, you can use a 2N2222or other small transistor, a resistor and latching relay. (I assume as an electrician you can safely connect the relay to the air handler.) Run the signal that operates the piezo through the resistor (probably 4.7K will work) to the base of the 2N2222. Emitter to ground, collector to relay coil, + to other side of relay coil. Put a backwards diode across the relay coil. See the following url:

I've been able to do the above - however you may need to add 2 components, and probably should. You add a diode and a 4.7 uf cap (the - side of the cap goes to ground) between the base resistor and the piezo. Polarity matters. The banded end of the diode goes toward the base and the + lead of the cap. If you use a pnp transistor you need to adjust the polarity accordingly.

Electronics? Nah.

As another poster noted, you can get pumps that have a switch that opens when the water level gets high.

Alternatively, you can get a "microswitch" with a lever that bears down on a aspirin tablet. When the basement floor gets wet, the tablet falls apart and the switch opens. The switch would be wired in series with the 24 volt control transformer.

There are some complications: sometimes the "outside" unit has it's own transformer and it may be a PITA to put the contacts in the "loop."

You might also consider putting a pair of revered LEDs in parallel and the combination in series with a resistor. Put this "network" across your sensor switch so that when you "lose your cool" you get some indication of what happened.

BTW: when consumers mess with HVAC wiring, you give an excuse for the installer to void guarantees.

When you do fool with the wiring do it in a way you can remove all traces of your changes. If something goes wrong that you need a repairman, you remove your modifications and look innocent when the technician arrives.

Even if there aren't warrantee issues, it's a good idea to remove your changes when you bring in outside help. No point paying someone $50/hour or whatever to waste time trying to figure out your wiring.

Just break the loop with a male/female "spade" connector pair. Then it's easy to patch in and out.

Why not? Your solutions don't work. Quoting the OP:

"The condensate line in my a/c backed up and I had a mess on my floor and carpet."

He clearly wishes to avoid that.

By the time the water is high enough, his carpet will be soaked.

Elegant - but again, by the time the aspirin disolves, his carpet will be soaked. You also assume a basement which may or may not be the case, but seems unlikely.

Enough water to melt a aspirin tablet near the air handler isn't enough to crease a "mess" on the floor and carpet. It's just enough to ensure there is a real problem. I have seen situations where the HVAC system operated when the condensate wasn't being put into the proper place. That's the problem: DAYS of drip by drip water damaging carpet and walls. A few quarts just doesn't do much damage. Its the GALLONS that make you call in the insurance adjuster.

That's the water level in the pump assemply. There are TWO switches on the float. The lower "notch" turns on the pump; IF the pump is working, the water will be safely away in about 10 seconds; if the water keeps rising the second "notch" kills the compressor.

Detecting water on floors in a way to keeps the FAR (false alarm rate) down in the noise is best solved with the aspirin rather than an electronic moisture detector. Floors pick up moisture and electronic sensors pick up contamination.

Maybe a small section of carpet will be a little damp. That's a LONG way from his carpet being "soaked."

The air handler is ALWAYS placed on "bare floor."

I haven't "aSSumed" anything. You put your aspirin detectes where the water would go if the pump fails or the draing gets plugged or whatever. An air handler that's not on the basement usually is placed in a pan that has a separate drain. You could put an aspirin switch in the pan and another on the floor near the pump assembly.