Looking for Time-Sensitive 12v Relay - do they exist?

[richardm47]

I'd like to have a relay switch controlling my noisy fresh water pump. We always forget to switch the burping thing off before going to bed. Guess who has to get up to switch it off! But is there a relay that will operate the way I have in mind?

I'd press a button once to make the relay provide current to the pump. Then the pump would stay 'active' for a timed period of say 15 minutes, after which the relay would switch the current off. Next person who wants water would press the button again to get 15 minutes of active service from the pump. A bit like stairwell lights in communal flats, where you press a button to switch them on, then they switch themselves off a few minutes later to save electricity.

Does such a relay exist for 12v systems? What are they called and where could I get one?

 

[earlybird]

http://www.polevolt.co.uk/acatalog/info_74205.html Any good? probably others as well
Add; since most mains light delay switches are pneumatic, AFAIK, one could offer a slightly cheaper solution, although less versatile.

 

[Phoenix of Hamble]

Another question is, why is your fresh water pump running at night?... you must have a leak somewhere!

 

[Trundlebug]

Maplins do a Monostable switch kit for £8.49, here
http://www.maplin.co.uk/p/555-monostable-switch-kit-n32fl

Adjustable up to 15 minutes.

 

[Trundlebug]

Another question is, why is your fresh water pump running at night?... you must have a leak somewhere!

Regardless of how water tight the system is, the pressure gradually bleeds away through the check valves in the pump.
But that's not the question the OP asked.

 

[emnick]

These people supply different types of timer relay.........as said I think you are curing the symptom not the cause.

http://handylittlemodules.co.uk/product/pt160/

 

[GrahamM376]

Just Google "adjustable time delay relay" and lots come up. Do you have n accumulator in the system? Our pump very rarely runs unless a tap turned on.

 

[prv]

Just Google "adjustable time delay relay" and lots come up. Do you have n accumulator in the system? Our pump very rarely runs unless a tap turned on.

Even without an accumulator, our pump hardly ever runs without a tap being turned on.

Pete

 

[AntarcticPilot]

Regardless of how water tight the system is, the pressure gradually bleeds away through the check valves in the pump.
But that's not the question the OP asked.

Mine doesn't; if I hear the pump running, it means either a tap hasn't been fully turned off, or there's a leak.

 

[Phoenix of Hamble]

Mine doesn't; if I hear the pump running, it means either a tap hasn't been fully turned off, or there's a leak.

+1 fix the cause, not the symptom

 

[richardm47]

Yes I realise I've got to fix the underlying problem, not just the symptom.

I don't think its a leak in the pipes but something in the archaic, arthritic pump, must be 25 years old at least. When we first got the boat 5 years ago I thought that pump will die soon and then I'll get a new one and have quiet nights. Already researched what to fit, know exactly what to replace it with. But the bloody pump keeps on working!

Now that I know that timer relays do really exist, I am thinking of other uses as well. I could add one to the light in the heads which inadvertently gets left on and then drains the batteries all night. In another thread today, someone is worrying that a pump left on and tap left dripping would eventually flatten the battery, which a timed relay would prevent. Probably many other uses - any ideas?

Thanks to all for expanding my knowledge. Earlybird linked us to a £35 relay on the polevolt site. Looking around that site I also found a rear-window-heater relay, which stays on for 10 mins after the button is pressed. That is only £6 so I think I'll give that a try. Great forum, many thanks.

 

[nigelmercier]

Could the pressure switch need adjusting?

 

[GrahamM376]

Now that I know that timer relays do really exist, I am thinking of other uses as well. I could add one to the light in the heads which inadvertently gets left on and then drains the batteries all night. .

Best thing for lights is to replace tungsten with leds. You get the same current draw from 20 led lights as one 24w tungsten. If we have visitors on board I always leave the light on in the fwd heads, at only 100ma it's not worth bothering about.

 

[superheat6k]

Possibly soft scale build up in the pump valves. A good soak in vinegar might sort it. If you need a new pump type Seaflo into the Ebay search bar. Cheap, quiet and effective.