Thread: testing condensate pumps

These small pumps are sometimes found in my area. Does anyone have a good protocol for testing them? I've been pouring water in to see if the pump works, which it usually does. However, the cut off circuit has never worked for me so far.

Is this supposed to work whether the pump is plugged in or not? The only way I've tested them it so unplug the pump, and fill it with water. I am under the impression that the AC system is supposed to shut down. So far it has not shut down any of the AC systems. I thought the float and disconnect were separate from the 120 volt power supply on the pump, and only tied into the control board for the AC and furnace (combined units here).

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The pump works just like a water fountain pump--fill with water, and it pumps it out.

Yes, I test them by adding water to the tank...while plugged in, just like in real use.

Rarely, the AHU is wired to shut off if/when the pump is full. It takes a little A/C wiring knowledge to place the pump's fill switch inline with the AHU.

Dom.

I lift the top of the pump up from the reservoir and lift the float to see if the motor turns on, easier than taking water into the crawlspace. The normally closed switch can be connected to the compressor control wire or the 24v, depends on what the HVAC tech prefers. If it is to the compressor you would have to go to the unit to see if it shut off. If it is to the 24v, the indoor fan would stop and you would know right away.

Most times it is not hooked to anything and needs to be written up as such.

Pretty much like I've been doing, then. The last two were wires into the control panel, so I was hoping one of them would shut down the system, but no luck. Job insurance for us, I guess.

Like has been mentioned, typically this would interrupt the 24V to the outdoor unit, not the AHU. I would not be surprised to see a large percentage of these switches that failed to open, but there should be a two stage operation depending on the fluid level. First the pump turns on and at a later (higher water level) stage the NC contacts would open to the condensing unit to stop the production of water (or shut down the entire system depending on the way it is wired) I can easily envision contacts sticking closed in that environment, but begin checking the outdoor unit, not just the indoor AHU.

Unless I can find the terminus of the drain line for the pump I do not test it, but rather disclaim it. I have only found a few where the terminus of the drain line could be located.

Never have I tested these pumps. Had one on my A/C for 10 years and never a problem, and the electrical was not connected to the A/C in event of failure.