Timer for Fuel Polishing System

[mvweebles]

Asking for recommended switch/timer for a fuel polishing system. 12VDC with a Groco Vane Pump, around 12-amps or so. Strong preference to simple spring-loaded timer switch vs digital readout. 4 or 6 hour time would be fine.

EDIT - does voltage matter on a simple SPST switch like this one made for 120/240VAC; 50/60hz?

https://www.intermatic.com/Catalog/us/Products/In-Wall-Controls/Spring-Wound-Countdown-Timers

Thanks in advance -

Peter

 

[READY]

There would be no problem using the switch shown with AC ratings for a DC application. 12V at 12 Amps. On the other hand you typically (Maybe never!) can use a device designed and rated for DC for an AC application. That would be a significant safety/fire risk.

 

[READY]

Just to clarify I am assuming that timer is operated mechanically via a simple spring type mechanism and not using the AC input to drive the timer.

 

[mvweebles]

Just to clarify I am assuming that timer is operated mechanically via a simple spring type mechanism and not using the AC input to drive the timer.

Correct, no power for the timer. I've tried the fancy digital timers and can never remember how to program them. The instructions are tiny, and the batteries fail.

Peter

 

[Mac2]

I had the same issue several years ago when I installed a fuel polishing system (DIY) on a Krogen Manatee with one fuel tank. I never found a 12 volt timer (simple spring type) and ended up using the 12 volt digital type timer. Once I figured out how to use the digital timer with all the different buttons for settings, I ended up loving it. I set it up to come on automatically once a week, which was great, for when I couldn't get to the boat.

 

[Mac2]

 

[kchace]

I used the same mechanical timer on my fuel polisher and it worked great.

Ken

 

[mvweebles]

Looks like this Amazon product

https://www.amazon.com/FAVOLCANO-CN...1648168917&sprefix=12VDC+timer,aps,193&sr=8-6

For reference, here is a picture of the wiring setup diagram posted by a reviewer. Apparently the instructions are not great (surprise, surprise).

I plan to use this more as a manual polish cycle when I have suspect fuel. I always forget how to program digital timers, though this one looks manageable.

Peter

 

[Island Cessna]

EDIT - does voltage matter on a simple SPST switch like this one made for 120/240VAC; 50/60hz?

https://www.intermatic.com/Catalog/us/Products/In-Wall-Controls/Spring-Wound-Countdown-Timers

Thanks in advance -

Peter

View attachment 127054

Peter, the answer is in this paper by Carling, makers of many of the switches we use. https://www.carlingtech.com/amp-hp-volts. As I interpret the paper (DC Rule of Thumb) the mechanical switch you are looking at is only good for 7 amps DC (based on the lowest AC rating (incandescent bulb). If I were doing your job I would probably use a small continuous rated DC relay, and the timer you selected to activate the coil.

Bill