Bilge Pump Switch with Timer Delay

[scurvydog_pnw]

Hi folks,

I had to replace our old sump pump switch recently and dropped in an SPX switch. The issue I found with it is that it has a mechanical on/off based on float inside. The sump box is small enough that we get some back flow from the hose which can retrigger the switch. We don't have a check valve in the discharge hose and don't want to put one in. If I manually trip the bilge pump switch it will actually pump the box deep enough with another 10-15 seconds that the back flow does not effect the switch.

Any make model advice for switches that will run for a time period after the water level drops below the switch/sensor?

Cheers

 

[lwarden]

Take a look at the Aqua Alarm, it stays on 15 seconds after triggering. I have two I'm installing in a few weeks on my boat and will report back.

20038 Smart Bilge Pump Switch - $99.95 : AQUALARM, Warning Systems For Land And Sea

AQUALARM 20038 Smart Bilge Pump Switch - Smart Bilge Pump Switch Smart Bilge Pump Switch, 20 amp rating Includes Smart Switch, Red Light Warning Panel (1/2" x 2-1/2"), Piezo Buzzer The Smart Switch switches the pump on when water is present. The Red Light on the warning panel is lit; showing...

aqualarm.net

 

[Nick F]

Change to a smaller diameter outlet hose - there will be a smaller volume of flowback. No moving parts!

(also, hose routing can reduce the flowback volume. Go high immediately then downhill to the thruhull)

 

[scurvydog_pnw]

All good suggestions. I had my eye on the Aqua alarm in the past but, did not know it had a 15 sec delay. I think I will throw one of those in this weekend.

 

[Lepke]

On eBay you can find 12v time delay relays for about $10.

 

[Mischief Managed]

On eBay you can find 12v time delay relays for about $10.

Only $7 on Amazon, if memory serves. I installed 4 of them on my boat to operate my two head fans and two shower drain pumps so that they are not accidentally left on all day. Simple, cheap and effective. Can set them from 1 second to 99 minutes and they have NO and NC contacts.

 

[HeadedToTexas]

I have the same problem with our small shower sump. The rising portion of the discharge hose contains enough water to put the level switch within a few ounces of actuating. That makes for frequency operation cycles and middle of the night pump runs.

How does a delay timer fix that? No matter hot long the pump runs, the back wash volume creates the same problem.

 

[rslifkin]

I have the same problem with our small shower sump. The rising portion of the discharge hose contains enough water to put the level switch within a few ounces of actuating. That makes for frequency operation cycles and middle of the night pump runs.

How does a delay timer fix that? No matter hot long the pump runs, the back wash volume creates the same problem.

It helps in situations where the minimum level the pump can draw down to is lower than the float turn-off level. You can't set the float so it turns off right where the pump sucks air, as it won't reliably turn off in that situation. So if the float cuts the power with the water still half an inch higher, keeping the pump running for a few extra seconds will remove more water.

 

[Frosty]

It helps in situations where the minimum level the pump can draw down to is lower than the float turn-off level.

I didn't realize there was a solution like this. Looking into it now thanks to this thread

I have a shallow sump and already am down to 3/4" hose, plus started "fall" of hose to exit through-hull as quickly as possible. Still find that the amount of water that comes back is equal to when the pump starts up again....endless cycle.

I wish there were a little more information on the Aqualarm site. "Starts at $99" but then it seems you have to choose one of the "custom" wire lengths which are $10 minimum. I don't see any supporting info (tell me more about this wire, give me dimensions of the whole thing, at least show a diagram, etc.). Maybe I just haven't found it yet.

Or... maybe it's time to dive into the (for me) scary world of Amazon 12v time delay relays..... then I could presumably use the (Water Witch) switch I already have. If anyone has used a specific one successfully and would want to post a link, I'm all ears.

(I did wire a Bosch relay for the first time last fall.... so that a Contura switch could switch on/off a 40a autopilot pump....boat still floating.)

 

[lwarden]

Yeah, the Aqualarm site and purchasing is a little funky. I think they are missing and opportunity to just provide the switch without the alarm panel and associated wiring. They could offer that for $10 less and people like me that don't want the alarm wouldn't be throwing away the little panel and buzzer. I think the switch is a pretty good design from what I've see of it, but the mounting could be better. I 3D printed up some brackets to attach it directly to the pump housings since I don't have a vertical wall where I want to mount them. I'm installing them today and will try to remmember to take some pictures.

 

[WillieC2]

Is anyone concerned about using relays with contacts not specifically rated for DC?

 

[scurvydog_pnw]

To circle back and close the thread out. First thanks for all the great advice. Iended up going with the Aqualarm 12V switch which resolved my issue. Two things helped.Unlike the existing switch it does not need to be mounted on the bottom of the sump box. So I raised it up a few inches. Now when the pump kicks on + 15 second delay it drains down the water level to just the minimum point that the pump can suck up.

Cheers

 

[Comodave]

I went a different route and used a Whale Gusher IC with the remote pickup and sensor. It comes with a check valve so no back flow. Works great. Formula runs everything to the shower sump so the sump box is rather large. The Gusher has been very reliable at 3+ years.

 

[lwarden]

You beat me to it. I installed two of them over the weekend including the custom 3D brackets to attach them to the pumps. They work great! The yellow alarm wire was connected to the indicator light on one of my pumps which although isn't an alarm, give an indication on the panel the pump is running.

The 15 second delay is perfect for draining a sump for the one with the red Johnson pump. Worked exactly as you would expect and pumped it dry except for a bit of flow back from the line when it shut off.

Overall I think these are the current go-to pump switch for the money, especially considering the delay off feature and small size.