Booster Pump Pressure Switch

[Rockrila]

In the process of building an RO. I am using a shallow well 3/4 HP pump for a booster pump. Not sure is I should incorporate the pressure switch that came with it. Thinking that there would be a lot of off and on while processing sap. The pump's manual says not to exceed 50 psi. Not sure what psi will result as I run it against the 5 micron filter / 330 gph procon / XLE 4040 membrane.

Rockrila Mapling
2014 - Build 2x6 evaporator
2015 - 117 taps
2016 - 154 taps
2017 - Building RO, planning for 220 taps

[Wanabe1972]

I have added a pressure switch to my RO pump as i use the pump for all operations in the sugar house to move sap/permeate. I have a switch tied into pressure switch so when the switch is on the pump runs continuous. I use this for moving sap, filling head tank and running the RO. When the switch is off the pressure switch takes over and I can run my sink for cleaning using permeate and I have a hose with a spray nozzle for cleaning evaporator or tanks. This works pretty slick and the pump is only running when needed

[Bricklayer]

Don't quote me on this but I think with the pressure switches that come with wells are for the most part set at 30-50. ( Pump on at 30 or below and off at 50 psi
I think on most of the pressure switches the top end pressure in this case 50 is adjustable. But not the low pressure. It's the big screw with the spring on it I think. If you were able to crank it up all the way say to 65 or 70 I don't think the pump will start and stop. And then you have a low pressure cut out also. Would have to make sure it stops your Procon also somehow. I do remember reading on here in a thread that you can pinch one of the lines off also to fool the pump. Might be the high pressure (50 Psi line) I could be wrong on this so hopefully someone that has used a well pump with the pressure switch attached will chime in.

[Clinkis]

Don't quote me on this but I think with the pressure switches that come with wells are for the most part set at 30-50. ( Pump on at 30 or below and off at 50 psi
I think on most of the pressure switches the top end pressure in this case 50 is adjustable. But not the low pressure. It's the big screw with the spring on it I think. If you were able to crank it up all the way say to 65 or 70 I don't think the pump will start and stop. And then you have a low pressure cut out also. Would have to make sure it stops your Procon also somehow. I do remember reading on here in a thread that you can pinch one of the lines off also to fool the pump. Might be the high pressure (50 Psi line) I could be wrong on this so hopefully someone that has used a well pump with the pressure switch attached will chime in.

That's exactly what I did. You crank up the high pressure shutoff and then the pump will run steady and if you run out of sap it will shut the RO down. You just need to wire it so both pumps get power through the pressure switch and put another switch in between so you can turn high pressure pump on and off as necessary.

[Bricklayer]

Don't quote me on this but I think with the pressure switches that come with wells are for the most part set at 30-50. ( Pump on at 30 or below and off at 50 psi
I think on most of the pressure switches the top end pressure in this case 50 is adjustable. But not the low pressure. It's the big screw with the spring on it I think. If you were able to crank it up all the way say to 65 or 70 I don't think the pump will start and stop. And then you have a low pressure cut out also. Would have to make sure it stops your Procon also somehow. I do remember reading on here in a thread that you can pinch one of the lines off also to fool the pump. Might be the high pressure (50 Psi line) I could be wrong on this so hopefully someone that has used a well pump with the pressure switch attached will chime in.

I thought about this more. If using a regular 30-50 well pump pressure switch it will not work for low pressure cutout switch. The pump will want to stay on on anything below the highest pressure setting. So you will have to pinch off or cap the low pressure tube from the switch. This will trick the pump into thinking it's always operating under low pressure and will only cut out on the highest pressure setting maybe 65-70 psi I would assume.
It is possible to just take the pressure switch off and not even use it. Use a contactor instead.

[Brian]

They make another pressure switch with a lever on it, this switch will shut the pump off if the spring runs out of water, but to start them you have to hold up on the lever until it takes prime and reaches the kick on pressure.

[Bricklayer]

That's what I have on my well. Never even knew what it was. Good to know. Would work on an RO I guess as long as you don't mind holding it down when it starts.

[Clinkis]

This is the type of pressure switch I use. Just hold lever up until the feed pump primes and your good to go.