How do I Monitor my Septic Pump?

I recently had my septic tank pump burn out and coincidently, the high water alarm in my garage was also fried. So the thing did not go off when the water level in the tank filled and the high water float switch closed. Luckily, I noticed the breaker had tripped and figured something bad was happening.

My new pump is installed and I think I would like to monitor the float switch with my ELK. But I would also like the garage alarm to sound when the switch closes as well. Currently, it appears the float switch provides 120V power to the alarm. I know I can't run 120V to my ELK.

Would I run the float switch wires to my elk? Then run 24 volts from an ELK output that flips a relay providing 120v to the garage alarm?

OR do I just add a redundant float switch in my tank that is just for the ELK?

It depends on the current capability of the 120 vac that is switched to the alarm, but I would consider getting a 120 vac coil relay, then just connecting the relay's terminals to an Elk zone.

It this was me, I would also consider monitoring the current of the pump as well. It would be nice to see that come on when the alarm was tripped, then you know it is working.

I've recently been playing around with this Relay in a Box (RIB) model RIBXGTA, which will not give you a current reading directly, but will provide a contact closure when the current is in a specific range. It wasn't that expensive either.

Of course you would have to size one to your pump's current specs.

Others here will probably have ideas as well!

You could also use a water bug WB-200 or similar device.

I would also consider another float switch that is not tied to any high voltage devices. You could monitor the float switch directly with an elk zone.

What type of float switch do you currently have?

A second float switch would be good as it is totally independent of the existing system. Thus no failure in the existing system would cause it to fail. But unless it is tested occaisionally you won't know if it fails until the existing system fails and then it will be too late.

Monitoring current or on time of the existing float switch would also be a good backup. You could use a relay off the output of the float switch. Then time how long the motor typically runs and how often it runs. If it is on longer you know the pump isn't working. Current alone won't tell you the whole story so I think run time would be better but I haven't spent much time considering the possible failure points.

Instead of a float, you could mount a gri 2800 to the side of the pipe that your pump mounts to at whatever level you want the alarm to sound. A small piece of wood with a pipe strap holding it to the pvc pipe will provide a mounting plate for the gri. Hook that up to a zone on your Elk. The 2800 model is supervised sort of in that it has a powered relay in it and is normally closed. Configured with an eol resistor, If the unit breaks, gets wet, or has the wire cut, these will all be detectable by the elk.

You could even mount the gri at a height that is between the high level and low level for pump. You should expect that the gri should get wet every so often and stay wet for some period of time until the water gets high enough to turn the pump on again. Observing an ongoing cycling of this would prove that the pump is working. If the gri stayed wet for more than say 24 hours that could trigger an alarm.

A fancier solution would be to use one of the sonar distance devices to measure the height of the water. A number of people have been writing up how they use them to detect the salt level in their water softener tanks.

I can't see how a unit like the gri 2800 will be able to work well in dirty water and sewage. Get a piece of tp or a clump of **** stuck on the sensor and it will indicate water until it dries out (which may be never if mounted in the tank). And the electronics inside are probably not completely sealed for operation in a high humidity environment. A sturdy float with sealed switch will be much more reliable. The whole point of this is to have something reliable so why have a questionable sensor?

As far as using the time between cycles... I originally thought this would be good but what if you go away for a day or two? The system won't see any pump cycling and trigger the failure alarm. I suppose you could suspend timing when the alarm system is armed in away mode... The run time should be fairly consistent though so this could be used to indicate that the pump is functioning properly. You could look at current but the motor could be running and not actually moving any sewage so timing the run time seems like a better method.

gatchel said:

I would also consider another float switch that is not tied to any high voltage devices. You could monitor the float switch directly with an elk zone.

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I think I like this option best as it does provide a completely redundant system, independant from the pump circuit, and it will be hard wired. I had also thought about an Insteon I/O device which could monitor the switch, but that would not be as good or bullet proof.

gatchel said:

What type of float switch do you currently have?

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It's a Trident Mercury Switch (115VAC 15Amp). It still works dispite what the blackened alarm looks like. I'll be getting a new float switch when I buy a replacement alarm. I'm not sure who makes that one but it should work as an open/close circuit for the ELK to monitor. Thanks for your posts.

JimS said:

The whole point of this is to have something reliable

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I'm with you JimS (same initials as mine too). I want a dependable warning that the tank is full and it's time to stop the sh*t and get it FIXED before it's too late!

JimS said:

A second float switch would be good as it is totally independent of the existing system. Thus no failure in the existing system would cause it to fail. But unless it is tested occaisionally you won't know if it fails until the existing system fails and then it will be too late.

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Let's be honest. You really are supposed to test your system once a month anyway, or at least that's what the littel sticker on the keypads say...

JimS said:

I can't see how a unit like the gri 2800 will be able to work well in dirty water and sewage. Get a piece of tp or a clump of **** stuck on the sensor and it will indicate water until it dries out (which may be never if mounted in the tank). And the electronics inside are probably not completely sealed for operation in a high humidity environment. A sturdy float with sealed switch will be much more reliable. The whole point of this is to have something reliable so why have a questionable sensor?

As far as using the time between cycles... I originally thought this would be good but what if you go away for a day or two? The system won't see any pump cycling and trigger the failure alarm. I suppose you could suspend timing when the alarm system is armed in away mode... The run time should be fairly consistent though so this could be used to indicate that the pump is functioning properly. You could look at current but the motor could be running and not actually moving any sewage so timing the run time seems like a better method.

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You must not have septic. The final tank that pumps to the field is clean water. I'm not saying put it in a drinking glass and gulp it down clean water, but it is clear and provided you keep it chlorinated, odorless (even without chlorine it really has nearly no odor). If it is not, then you have other problems. Eventually you get what the call "sludge" in that last tank, but it is like silt. Nothing that would clog up a gri. It would clog up the tiny little holes in your drain field pipe (which is why there are filters that you clean once per month between the pump and the field) eventually which is why every 5 years or so you get the whole thing pumped. The gri doesn't have any issues with humidity. They are fully sealed submersible devices.

The raw sewage is in the first tanks (one tank with two baffles). With aerobic tanks (which are pretty much code everywhere now), the raw sewage flows into the first tank, the shit settles and then it flows over a baffle to a second section of the tank where an aerator mixes and oxygenates the water around a honeycomb of bacteria laden pieces of plastic that break down the remaining wastes. This stuff settles and the water flows over another baffle that allows any sediment to settle back to the second section and the clean water flows out a drain pipe to the holding tank.

No self-respecting home-owner opens the lid to the primary tank more than once. I, of course, did it just out of curiosity. I will NEVER do it again. You can not un-see these things! The second section of the first tank is already massively better. That should be opened monthly to ensure proper function of the aerator. Surprisingly the scent and un-wordly disgust of the first section of the tank is already 99% gone.

I agree that cycle times are not terribly good because no water in means no cycle. If you aren't home, then there will be no cycles.

gatchel said:

Let's be honest. You really are supposed to test your system once a month anyway, or at least that's what the littel sticker on the keypads say...

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Yes, but you can easily fill a holding tank up in a couple weeks (or days). .. especially if your bone head installers didn't seal it up from rain water getting in. I have had mine fill up after we got 6 inches of rain one night. . . and the filter was slightly clogged preventing a quick pump out. I cleaned the filter and set the pump to run continuously (instead of the 10 minutes every hour normal cycle) and it drained it to the field in a few hours.

Actually, I do have a septic system. But I was thinking sewage ejector tank like might be in a basement to pump up the sewage to the input of the septic tank. In any case the float switch will be much more reliable than something that relies on conduction and has corrosion of the contacts in the humid atmosphere.

I looked up the data sheets. Nowhere does it state it is submersible. It would if it was actually good for that. In fact it states:

After installation these units should be tested with
water and inspected annually. If there is any corrosion or
damage the sensor should be replaced.

These look like they are to be placed where there normally isn't water for occasional water contact. You can do what you want but I would never use these for this application.

JimS said:

In any case the float switch will be much more reliable than something that relies on conduction and has corrosion of the contacts in the humid atmosphere.

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I think you would be mistaken to assume this. I had a float switches fail on a sump once. They get tangled/stuck or they just stop responding to up/down. This is the reason they put timers on the pumps. So if the float gets stuck on, the pump only runs for 10 minutes every hour or whatever it is set for instead of just going continuously until it burns up.

The GRI has a lot less risk. If it fails, it will fail to the alarm mode whereas a float switch that is 99% of the time in the down position would tend to fail by staying in the down position (non-alarm) when it should be up (whether physically down or just electrically). The GRI is a normally closed, eol resisted, connection that is supervised in the sense that you know the connection is good and the internal relay is functioning. The float switch would be normally open with no way to know if the unit were broken or wires broken without a hands on test.

The Septic maintenance book tells you to check the float switches monthly (along with clean filters, add chlorine, check aerator, check sludge level). Everything says that. It's a CYA thing.

I'll call GRI tomorrow and ask about humidity and immersion. Though immersion shouldn't be an issue since you would expect that your tank never or nearly never would overfill. I am not sure that humidity in the holding tank is all that high anyway. All the stuff above water is dry (no condensate) when I service it.

EDIT: The GRI 2808 is fully submersible.

JimS said:

You could look at current but the motor could be running and not actually moving any sewage so timing the run time seems like a better method.

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You can tell a lot by watching the current of a pump. Normally, a pump in optimal conditions will be running at xxx amps. If it's clogged, the amps are higher, and if it's running dry, the amps are lower (no strain). It's actually a pretty good way to monitor the health of the pump and watch for out-of-normal conditions; also combine in run-time and time-since-last-run and you can see if it hasn't turned on (breaker blown/bad float switch) or stuck-on (bad float switch).

Work2Play said:

You can tell a lot by watching the current of a pump. Normally, a pump in optimal conditions will be running at xxx amps. If it's clogged, the amps are higher, and if it's running dry, the amps are lower (no strain). It's actually a pretty good way to monitor the health of the pump and watch for out-of-normal conditions; also combine in run-time and time-since-last-run and you can see if it hasn't turned on (breaker blown/bad float switch) or stuck-on (bad float switch).

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Very good points. You can tell a lot from current and run times. But you should verify what the current does for different conditions. If the inlet or outlet is blocked the current usually goes down, not up.

Work2Play said:

You can tell a lot by watching the current of a pump. Normally, a pump in optimal conditions will be running at xxx amps. If it's clogged, the amps are higher, and if it's running dry, the amps are lower (no strain).

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I have been proven wrong on that point. Depending on the type of motor some draw more amps when "running wild" (low resistance, rpms go up, and current goes up). My understanding is that centrifugal pumps (typical water pump) are all like that. Other motor types are the opposite. My table saw for example draws more amps when it has a load. Vaccum cleaners and most air handlers also go up on current when flow is blocked.

I believe it is because the load of these types of pumps goes down when flow is blocked. The resistance to flow is from the acceleration of the fluid/gas as it passes through the blades. When flow is blocked, the substance runs around in a circle and doesn't load the motor. Listen to a vacuum cleaner for example. When you plug the inlet the rpms go up. A positive displacement pump is the opposite (piston type).