Need an idea to connect a pump

[PinGuy]

Scenario is this:

Refrigerator.
Low water pressure.
Ice cube maker will not fill the cups entirely, so it makes hollow cubes.
It takes 1 full minute to fill a 1/2 liter glass through the water dispenser.

Refrigerator is OK, problem is the pressure on the pipes.
So I want to add a 12VDC pump which I already have and have tested and works beautifully.
The fridge has two coils, one for the water dispenser, one for the ice maker.
I want the pump to start when either coil activates.
I'm planning to add one 12V power supply in parallel with each 110V coil, with their outputs also in parallel, connected to the pump.
I know this will likely work, but is it possible to drive this with a single power supply and few components instead? Any lights on this would be awesome

[petehall347]

Re: Need an idea to connect a pump

try a pressure vessel first . all it needs is pumping up .

[redwire]

Re: Need an idea to connect a pump

Are you sure- it's such low pressure 500mL/min is pretty poor.
Or is the piping/line blocked or kinked?

[brethin]

Re: Need an idea to connect a pump

the filter is probably gunked up.

[Curious.George]

Re: Need an idea to connect a pump

Are you sure- it's such low pressure 500mL/min is pretty poor.
Or is the piping/line blocked or kinked?

Easy enough to check -- disconnect the flex line to the refrigerator (AT the supply, not at the refrigerator) and see how long it takes to fill that half liter bottle.

The line TO the refrigerator is likely a very small I.D. and easily clogged -- as is the line INSIDE the refrigerator. A blast of air can help, there (back flushed).

[Curious.George]

Re: Need an idea to connect a pump

So I want to add a 12VDC pump which I already have and have tested and works beautifully.
The fridge has two coils, one for the water dispenser, one for the ice maker.

The "coils" are the actuator solenoids for the water valves -- one to the dispenser and the other to the tray filler?

I want the pump to start when either coil activates.

What "switches" power to these coils? I.e., can you, instead, take those signals? Or, are they just mechanical switches? (e.g., our ice maker is just driven from a clockwork timer)

I'm planning to add one 12V power supply in parallel with each 110V coil, with their outputs also in parallel, connected to the pump.

Less than ideal as it adds the power supply (including any inrush current) as a load to be carried by "whatever" is switching power to those solenoid coils.

I know this will likely work, but is it possible to drive this with a single power supply and few components instead? Any lights on this would be awesome

You could select two small relays, each with 110V coils, and drive each of them in parallel with a corresponding coil in the refrigerator. (Take care to consider the switching capabilities of whatever is driving those coils). Then, run mains power to the contacts (form A) of the relays so that either of them can call for power for the power supply.

Or, find a 110V pump and skip the power supply, entirely.

[PinGuy]

Re: Need an idea to connect a pump

Thanks guys.
In the wall there's a 1/2 inch pipe, which takes about 5 seconds to fill up a 1/2 liter glass. The fridge doesn't have any problems or clogs on the pipes or hoses. The filter is brand new, installed at the time of first post. It's just the pressure on the building that is poor, and that, added to the reduction of the hoses inside the fridge to 1/4, reduces the pressure even more.

What "switches" power to these coils? I.e., can you, instead, take those signals? Or, are they just mechanical switches? (e.g., our ice maker is just driven from a clockwork timer)

Yeah, the mechanical switch you push with the glass to get water from the dispenser activates one solenoid, and the ice maker activates the other using a timer, for 6-8 seconds, every about 20~30 minutes until the ice container is full.

Less than ideal as it adds the power supply (including any inrush current) as a load to be carried by "whatever" is switching power to those solenoid coils.

Less than ideal, that for sure. But the power supplies output 12V 2A, so that won't hurt anything I guess even if I wire them directly to the coil's lugs. Plus it will be very unlikely for them to run at the same time.
I'm attaching the schematic of the fridge, which I found folded and hidden in the lower front bezel and scanned it right away. +1 Whirlpool for this!

[sam_sam_sam]

Re: Need an idea to connect a pump

If I were doing this —> this is how I would do this

I would put a fan relay ( 4 pole relay) switch where the water valve is just make sure that it is has a 120 volt relay coil in place of the water valve the way it is hook now two pole are for your water valve the other two are for your pump

Just make sure that the water valve and pump are powered separately from the power that use to be the for the water valve

Also make sure that your pump has a pressure switch that works otherwise your pump will not last very long

I understand this problem that you are having my wife is from Trinidad ( and yes I visit the country many times in last 25 years ) and most of the time there water pressure is very low or hardly any water at all—> and ice maker can not cope with very low water pressure

Do you have a 50 / 100 or bigger gallon tank how far off the ground is it

How often do you go with very low water pressure or no water at all and for how long

[PinGuy]

Re: Need an idea to connect a pump

I am not sure how to connect your idea, @sam_sam_sam.
How would your scheme work to activate the 4-pole relay when either solenoid activates?
The pump doesn't have a pressure switch. It would simply stop when the solenoids doesn't receive any power so no worries about over-pressuring, I believe.

[stj]

Re: Need an idea to connect a pump

12v pumps are used in cars for the windshield / headlamp washer - just saying.

[Curious.George]

Re: Need an idea to connect a pump

12v pumps are used in cars for the windshield / headlamp washer - just saying.

I'm not sure I'd want to use that for potable water -- esp if "used".

[stj]

Re: Need an idea to connect a pump

well your probably right, but in a hot country they probably dont use any chemicals in the water.
another thing that comes to mind is fixing the general house pressure with a booster pump.

[sam_sam_sam]

Re: Need an idea to connect a pump

I am not sure how to connect your idea, @sam_sam_sam.
How would your scheme work to activate the 4-pole relay when either solenoid activates?
The pump doesn't have a pressure switch. It would simply stop when the solenoids doesn't receive any power so no worries about over-pressuring, I believe.

I will try to draw one either later today or tomorrow when I get some time to do it

[goontron]

Re: Need an idea to connect a pump

I'm not sure I'd want to use that for potable water -- esp if "used".

Why not? If they are new then material wise they are perfectly foodsafe. They are made of either PVC or Nylon plastic. I can't see the shaft being anything but stainless steel, brass, or nylon in an ammonia environment like wisher fluid. Maybe the grease used on the shaft seal, but thats all i can think of.

[Curious.George]

Re: Need an idea to connect a pump

Why not? If they are new then material wise they are perfectly foodsafe. They are made of either PVC or Nylon plastic. I can't see the shaft being anything but stainless steel, brass, or nylon in an ammonia environment like wisher fluid. Maybe the grease used on the shaft seal, but thats all i can think of.

Plastics often contain lead. It can help make the plastic more "giving" (flexible) as well as a stabilizer for heat exposure -- like under a hood! In a windshield washer application, there's little concern over the lead leeching out of the plastic as it's just windshield washer fluid being applied to a sheet of glass.

Given that most of this stuff is sourced from China, you can almost EXPECT it to have lead in it if there's no contractual reason why it CAN'T.

I spent a lot of time searching for an NFS61-compliant motorized shutoff valve for the domestic water supply at the house. Lots of "valves" (inexpensive!) but when you want them for potable applications, a different market, entirely!

When talking with chinese suppliers re: having some plastic parts injection molded, "lead" is a four-letter word :-/ that they really don't like becoming part of the conversation (I think they like to rely on soft tooling and other process variations that expose the finished parts to "significant" levels of lead)

[Another colleague ended up moving his production OUT of China for this same reason]

[stj]

Re: Need an idea to connect a pump

why are motorised valves different?

the ones here are just regular brass with a solenoid or servo externally attached.

[Curious.George]

Re: Need an idea to connect a pump

why are motorised valves different?

the ones here are just regular brass with a solenoid or servo externally attached.

My initial (naive) hope had been that I could simply use a $20 (piloted) "irrigation valve" to gate the domestic water. It was the right sort of "action" (a ball valve takes far longer to transition from on<->off).

[Irrigation valves are similar to the valves used in ice makers, dish washers, refrigerators, washing machines, etc.]

The "potable water" specification killed that idea.

Gate valves suck -- esp in hard water areas. So, ball valve seemed the answer.

Manual ball valve: $20. Add motor and limit switches: $100 - $300.

My only explanation is they are probably sold in so much smaller quantities. (Or, the motor mechanism has to be "extra reliable" in the sorts of applications for which they are designed?)

I've had to rethink where I use them as I originally wanted to use them in several places around the house... :<

[stj]

Re: Need an idea to connect a pump

well a ball valve should cost about $5-10
as it is a 90' action, i imagine with a lever of the right length you could run one with almost instant action with a pair of beefy solenoids.

[Curious.George]

Re: Need an idea to connect a pump

well a ball valve should cost about $5-10
as it is a 90' action, i imagine with a lever of the right length you could run one with almost instant action with a pair of beefy solenoids.

For 1" ID and "lead free" (!), it's much closer to $20:

https://www.homedepot.com/p/LEGEND-V...01NL/203580994

It's tough moving the actuator by hand, let alone with a solenoid.

And, you have to add limit switches to verify the valve is fully open or closed (incompletely open/closed will eat the valve's lunch in short order).

So, motorized with limit switches -- and a backup power source (useless if you can't run the motor to fully open or close the valve in the event of an outage!).

[The motor actually makes the power source easier to support as the effort is not expended in a single "stroke". OTOH, the power source must stay up long enough for the motor to complete its action!]

[petehall347]

Re: Need an idea to connect a pump

how about a simple on demand pump and pressure vessel plumbed into the water supply ? it gets me a 60 psi shower here .
might have to adjust pump pressure to suit fridge .