water tank auto fill... and mixing question

[signal15]

I have a small water tank on an espresso machine that is ANNOYING to have to fill. If it goes empty, I run the risk of running the boiler dry and burning out the heating element, which is not cheap.

So, in the interest of making it auto-fill, I'm looking for a reliable solution to plumb the thing in. I found mini float valves for $10-15 all over the internet. I don't have a lot of faith in float valves, especially cheap ones. Just look at how often they go bad in toilets. I don't need it overflowing and leaking water all over the floor.

Any ideas? Maybe a normally closed, solenoid activated water valve? Maybe a combination of a float valve, and a separate water valve that can slam shut if the water reaches a certain level? Whatever it uses, it needs to be small enough to either fit in the tank, or fit under the counter.

Also, looking for a precision mixing valve. I want two water inputs to be mixed to one output, and be able to precisely set the amount of mixing that happens, like 74% from one input, and 26% from the other. Ideas here?

 

[Quixote_1]

I have a small water tank on an espresso machine that is ANNOYING to have to fill. If it goes empty, I run the risk of running the boiler dry and burning out the heating element, which is not cheap.

So, in the interest of making it auto-fill, I'm looking for a reliable solution to plumb the thing in. I found mini float valves for $10-15 all over the internet. I don't have a lot of faith in float valves, especially cheap ones. Just look at how often they go bad in toilets. I don't need it overflowing and leaking water all over the floor.

Any ideas? Maybe a normally closed, solenoid activated water valve? Maybe a combination of a float valve, and a separate water valve that can slam shut if the water reaches a certain level? Whatever it uses, it needs to be small enough to either fit in the tank, or fit under the counter.

Also, looking for a precision mixing valve. I want two water inputs to be mixed to one output, and be able to precisely set the amount of mixing that happens, like 74% from one input, and 26% from the other. Ideas here?

Do you own an Elk-M1G?
I'm working on a similar project, but I'm too worried about having the potential to pour a virtually unlimited amount of water into the home if something fails. For that reason, I've shied away from plumbing directly to the water supply. My project is an aquarium auto-top-up system.
The direction I have chosen is probably a little more expensive, but worth the peace of mind. I will have a separate reservoir of approximately
50 liters of water with a pump at the bottom with a hose leading to the tank. The pump will be activated by a relay on an Elk output. Both the tank and the reservoir will have leak sensors at a low level and a top level. Once the leak sensor at the low level of the tank is no longer closed, the pump will activate if the sensor at the low level of the reservoir is closed until the sensor at the top of the tank is closed, or the sensor at the bottom of the reservoir is opened. The reservoir will be filled with a quick connect hose that will attach to a faucet, and an audible alarm will sound when the reservoir's top sensor is closed. The reservoir will still need to be filled once in a while, but it will reduce the hassle and it will be simple since the system will alert the person filling the reservoir when it is topped up.

 

[networkcrasher]

Is it a vibe pump or a rotary pump? Your best bet is to just plumb it in with polypro tubing, john guest fittings, and install a water sensitive cutoff that works with john guest fittings. The Leak Controller LCS is the model I have (in 3/8", but you will be perfectly fine with 1/4" tubing). You might also need a pressure regulator on the line if you want to control pressure to the puck across line fluctuations.

If it's a vibe pump, be aware you'll need to install some sort of solenoid in between the water supply and pump as the vibe pumps don't stop incoming pressure when they're not running. Rotary pumps DO stop line pressure when they're not running.

I have a high end italian espresso machine, and have been around the block with these machines..

 

[networkcrasher]

Oh, and the mixing valve - are you looking to do temperature profiling or pressure profiling? Lots of folks have tried this before...

 

[mwheeler42]

I have a la Valentina, and it is plumbed in as noted above. It replaces the tank entirely, so fit isn't a problem. I don't have the leak controller, but will buy one when I move. Without knowing exactly which model machine you have, it's hard to make an informed suggestion, but I'm sure the folks over at CoffeeGeek and other forums will have addressed a solution for your model.

 

[signal15]

Yes, I have an M1G. But I don't have a good place to put a big tank. I don't trust my M1G enough to allow it to control something like that. I see weird problems with rules sometimes.

I'm thinking electric float switches instead of valves. Put two float switches at the same level, and then put the solenoid valves in series with each other. You'd need to have both valves fail, or both switches fail at the same time to get an overflow.