Water pump timer

[msiminoff]

This is a very simple an inexpensive mod that I has been on my to-do list for quite a while... I added a time-delay relay to my water pump's electrical circuit so that the pump will turn itself off after a preset amount of time.

As part of the job I added a pushbutton switch in the bathroom for those times when we forget to turn on the pump before closing the door. In addition, I swapped out the rocker switch on the TC 's electrical control panel for an identically sized one that is momentary rather than on/off.

I chose a Hella 996152131 relay which has a user-selectable delay from 0 to 900 seconds. There are less expensive relays out there with the same functionality, but this one is plug-compatible with the Hella relay I installed ~10 years ago, so that made it a no-brainer.

At the moment the timer is set to about 14 minutes which is longer than it takes to wash the dishes, shower, or use the restroom.

Here are a few pic's...




The time delay is selected using these dip switches and trim-pot.


I found a small chrome momentary pushbutton at Napa so we can switch on the water pump from inside the bathroom.



Cheers,
-Mark

[HMS_Beagle]

Since the water pump normally cycles even when the tap is open, ideally you would have a time delay relay that is reset at each turn-on transition, and limited to say 3 minutes. You would need to tap into the pressure switch for the signal, but it would be easy to do. Just as much a problem as a burst pipe, is sucking air on a nearly empty tank at the start of a 6 hour drive, and having the pump run the entire time. Jabsco makes a pump with these features built in, but all done with electronics and reliability reports have been poor.

[msiminoff]

corvettekent wrote:
Why not leave the switch on all the time?

Fair question, although I have always wondered Why keep it on?

I prefer to keep my water pump off when not in use for the reason that Artum Snowbird mentioned... in the event of a leak the pump won't drain the fresh water tank. Point in case; A few years back I had a leak at the city water inlet check-valve. The tank drained while I was driving and the pump kept running (dry). I heard the pump whirring when I stopped for fuel and I went inside and shut it off, fortunately the pump survived.

In addition, I have always used a relay located at the water pump, along with dedicated 10ga wiring from my distribution panel to the pump. This ensures that there's plenty of current available to run the pump. The current draw of the relay's coil is only ~160mA, but to me every Watt counts.

This mod also allows me to have multiple on switches without the need to wire a 3-way switch or wonder if one switch was left in the on position. I do plan to add another pushbutton at the exterior shower before spring 🙂

bbaker2001 wrote:
Question... is it normal to lose pressure after some time.

Other than the one time I had a leak at the check-valve, my system has always been water tight. Even after sitting for many days, the pump does not cycle when I turn it on.

Cheers,
-Mark

[Joe417]

I had been planning on adding a switch in the bath. Great idea, I'll be following your lead.

Thanks,

[bbaker2001]

great- now no more yelling turn on the switch.


have a question. I turned on the pump to see if I had a leak anywhere and see if it would cycle. after 2 hrs of not coming on, I turned it off and did not turn it back on for 4 days. when I did, it started pumping again. is it normal to lose pressure after some time.

[Artum_Snowbird]

As many have realized, if you develop a leak, the pump will spew the entire contents of the water tank out gladly to satisfy the falling pressure.

A very clever mod indeed!

[corvettekent]

Why not leave the switch on all the time?