sump pump switch false alarms

HI,
 
On my Elk M1 I am using 2 zones as monitoring points for my septic tank and pump station levels.  For each zone I installed a sump pump switch that is NO (see picture).  When level gets too high I get my "close" status and and alarm condition.  All works well except that I occasionally get false alarms on EITHER of the zones.  I would consider faulty equipement or wiring if it was on one of the zones but on both I don't get it.
 
Any idea on what is happening?  Should I be taking on of the leads to a ground or adding a resitance in serie?  The false alarm is only temporay as I connect into my pannel and the condition is gone
 
 
 
 
 

How are the units connected to the M1? The unit you posted is wired via 110, which would put a ground reference on the zone, not good. What are the specific make/models of the units? I would believe either a ground fault or something similar, even possibly a too-fast zone response time.
 
Details

Have you measured the resistance of the contacts you are using?
 
Perhaps these contacts bounce or present a high resistance that the Elk input is sensitive to but a pump motor wouldn't be,

kojack said:

HI,
 
On my Elk M1 I am using 2 zones as monitoring points for my septic tank and pump station levels.  For each zone I installed a sump pump switch that is NO (see picture). 

Click to expand...

If I take the above literally then you are attaching your Elk zone to a 120 VAC switch? How exactly are you connected to the elk?
 
Mike.

Ok, I guess I was not clear
 
There is no 120 volt involved.  I have cut the 120 volt connector and simply use the switch as a Normally Open (NO) connected directly to the zone of the Elk.  I am doing this for 2 zones (2 switches).  As for the ground wire of the switch I simply ignore it as it is for electrical safety for 120 volts.
 
Interesting theory for the contacts to be bouncing.  or the high resistance of the switch.  I will measure the resistance and see.  But i only get the false alarms about once every 2 months.  and when it happens I will get several in the same day.
 
I am considering to use 12 volt DC relays and have my sump pump switch activate the relay on an alarm that will then have its contacts to the zone of the Elk M1.  This would isolate the potential problem of the switch  internal resistance sensative to the Elk M1 input   

If the float that is connected to the M1 is independent of the float that operates the pump, is it possible that the water level is actually getting high enough to trip the M1's float, but then by the time you check the float, the pump has pumped the level down to normal levels again?   Or are you certain that there is no water entering the sump pit when this is happening?

Hi RAL
 
To answer your first question the float switch connected to the ELK is independant to the float activating the pump (2 different switches).  So the switch connected to the ELK  is set up at a level higer and should only trigger if the level gets too high  (pump fail or AC outage).  When I got my false alarms neither of these conditons occured.
 
FYI,  When I get a high water level alarm I have set up a rule that:
          - turns off the main water valve (to prevent the level from getting higher)
          - beeps my keyboard
          - sends me an email
 
Maybe I could set up another rule that would verify if I get a high level every 10 seconds with a counter and if I get 2 alarm occurrences in a row than it is more likely that I have a problem.    But my real question is why am I getting these occasional false alarms

If I was convinced that there was no wiring problem with the zone circuit then I would change the switch that is connected to the zone. I had a window that was very occasionally reporting a violation and I couldn't find any fault with the wiring so I replaced the switch and the problem hasn't occurred in over a month now. It is next to impossible to ttest an intermittent problem with a switch and they are usually pretty inexpensive to replace.
 
Mike.

I will look into replacing the switch.  But as I said I have 2 similar setup with the same switch and the same intermitent problem (septic tank and a pumping station). 
 
I think I will add a rule that will require at least 5 continuous seconds of "fault" before taking action.  I hope that the rule below will be ok. 
 
I based my rule on the one provided by Elk applications notes using counters for the open doors.  But I added an entry (2nd line setting the counter to 5 when the zone becomes secure) as I beleive the rule was incomplete on Elks web site
 
 
 
 
WHENEVER water level (Zn 1) BECOMES NOT SECURE
THEN SET water alarm (Counter 1) TO 5

WHENEVER water level (Zn 1) BECOMES SECURE
THEN SET water alarm (Counter 1) TO 5

For every second that the water level is at fault, the counter will be decremented by 1.

WHENEVER EVERY 1 SECONDS
AND water level (Zn 1) IS NOT SECURE
THEN SUBTRACT 1 FROM water alarm (Counter 1)
 
Arter 5 consecutive seconds of fault the counter will be at 0

WHENEVER water alarm (Counter 1) CHANGES TO 0
THEN TURN water Shutoff (Out 3) OFF
 

kojack said:

Hi RAL
 
To answer your first question the float switch connected to the ELK is independant to the float activating the pump (2 different switches).  So the switch connected to the ELK  is set up at a level higer and should only trigger if the level gets too high  (pump fail or AC outage).  When I got my false alarms neither of these conditons occured.
 
FYI,  When I get a high water level alarm I have set up a rule that:
          - turns off the main water valve (to prevent the level from getting higher)
          - beeps my keyboard
          - sends me an email
 
Maybe I could set up another rule that would verify if I get a high level every 10 seconds with a counter and if I get 2 alarm occurrences in a row than it is more likely that I have a problem.    But my real question is why am I getting these occasional false alarms

Click to expand...

 
I've encountered flaky float switches before that don't always turn on when they should, or fail to turn off. 
 
What I was getting at with my previous question was this.  Suppose that the float switch connected to the Elk isn't the one that is flaky.  Suppose it is the float switch that controls the pump itself.   If the pump switch sometimes fails to turn on when it should, that would allow the water level to rise to the point where it triggers the switch to the M1.  As the water level continues to rise, the pump switch might finally turn on, and then the water level drops back down and both switches turn off.  By the time you are able to check up on why you received an alarm, everything looks ok.
 
In my experience, it is more likely that the switch that is carrying a significant load will fail, and that would point to one that controls the pump.
 
Adding some rules to require a longer contact closure might help you narrow this down.  It would help to know whether the pump actually runs at the time you get the alarm, as that would tell you whether the water level was near the trip point or whether the false alarms are independent of the water level.

To rule out the switch, before going ape...over the programming, why not remove the dry contact from the panel and run the unit through an isolation relay. Rules out resistance and swingers.

Measure the voltage at the input to the Elk input with a simple DC voltmeter when the contact operates.
A mercury tilt switch may have too much resistance to actual operate the input reliably.
 
These contacts are made for higher powered 120vac equipment that ignores a little contact resistance and burns off the oxide on the contact's surfaces.

LarrylLix said:

Measure the voltage at the input to the Elk input with a simple DC voltmeter when the contact operates.
A mercury tilt switch may have too much resistance to actual operate the input reliably.
 
These contacts are made for higher powered 120vac equipment that ignores a little contact resistance and burns off the oxide on the contact's surfaces.

Click to expand...

 
Note that many/most float switches these days do not contain mercury.

Thanks for the feedback.  I'lll verify the cabling and sump switch  with a multimeter (not the most pleasant place to play in!!).  I will go with relays to isolate from my Elk zones.  I probably should have done this day one.
 
 
Jacques

LarrylLix said:

Measure the voltage at the input to the Elk input with a simple DC voltmeter when the contact operates.
A mercury tilt switch may have too much resistance to actual operate the input reliably.
 
These contacts are made for higher powered 120vac equipment that ignores a little contact resistance and burns off the oxide on the contact's surfaces.

Click to expand...

Probably not a mercury switch.  But the concept still holds.  The switch is rated a 1/3HP+ pump, not a 12VDC signal....  How about a 120VAC relay on the float switch?
 
Good topic, I thought about adding some type of sump pump failure sensor to my M1G based system.