Pressure reducing valve, should be put before water presure tank or after pressure water tank

[jianhuayegreentree]

Hi, I am new here. Try to install new booster pump to add water pressure to my city water. City water only have about 30psi and I need to boost up to 60 psi. I sized a pressure tank of 20 gallon and pump booost the pressure to 60psi or more. So I want to add a pressure rducing valve. should I add between the pressure tank and booster pump or put after pressure tank? Thanks for your help.

 

[Valveman]

Why would you want to boost the pressure then use a valve to reduce the pressure down again. To get 60 PSI at the house you need a boost pump with a 50/70 pressure switch. The switch will shut the pump off at 70 PSI and you don't need a reducing valve. The pump also doesn't care if there is 30 or 60 coming into it, so a reducing valve on the inlet is also not needed. A 20 gallon size pressure tank is also a waste of money and space. What you do need a a regular shallow well jet pump and a PK1A for a booster system instead of any of those variable speed or flow controlled units that are made to sell, not to last.

 

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[jianhuayegreentree]

@Valveman , thanks for your response. I did not know you repsonded to my post earlier as I could not find my post. Finally today I use advanced search to find my post. My neighbor use the Davey BT14-30 pump and I see how his setup. The reason I use the reducing valve is I don't want the pump to boost too much pressure. My city water is at 28psi. I have installed the system today and found the pump does boost the pressure over 60psi. And my reducing valve does the job to control the pressure. I found 55 psi is best for my tankless toilet, not too strong and too weak. The reducing valve does the trick to keep pressure stable and pressure tank works to keep pressure not fluctulate that much if not much water use. But it seems that Davey pump is not doing what it is suppose to do. It supposed to have 20% pressure cutoff to start the pump. But my test shows that less than 2 quart of water used and no noticeble pressure drop will trig the pump to start. And after the pump starts it will run about three miniutes then stop which is different from neighbor's Davey pump. Not sure why it has to run three minitues as there is no noticebale pressure change. Maybe the controller is defective.

Valveman, you are right I probabaly just need a shallow Wet Jet pump with 40-60 psi pressure switch. Hope to know you better to just get the P1AK. Any suggestion for a Wet Jet pump at this moment as I already build up the piping system ( I can switch one of the water pressure meter with 40/60 pressure swith that comes with the tee) (see inserted photo). Thanks.

 

[Valveman]

Yeah almost every pump manufacturer has one of those little "tankless flow control" devices that stick up from the discharge of the pump. They are made to be easy to install, as they shorten the pump life and need to be installed often. Installed often is the most important design characteristic pump companies use today.

The reason is has to stick up from the pump is it has a flow switch inside. Anytime the flow starts there is enough to lift the little flow switch and the pump comes on. It doesn't matter how big a tank you have. If it leaks down slowly, there is a pressure switch that will also start the pump, but it only works with a very small leak, not an open faucet. Then once the flow switch drops when no more water is being used, there is a timer that makes the pump stay on for another minute or three, to keep the pump from cycling on and off rapidly. These devices have no control over the pressure and the house pressure is just the max the pump can build, PLUS the added pressure coming into the pump. Adding a relief valve is a bandaid for this problem, but also keeps the pressure tank from doing anything. Only low head cheap pumps will work with that device as a good jet pump will build too much pressure and a relief valve would ALWAYS be needed.

Working a pump at deadhead pressure with a timed off setting is not good for any pump. But just like all the others with a "Presscontrol" type device as control, they are easy to replace and you can just pick up a new one every year or two.

A good jet pump like a J10S with a PK1A to control might last 30-50 years, and that is certainly not good for the pump
business.

 

[jianhuayegreentree]

Thanks Valveman for your help. I will keep in mind your suggestion and may proceed with the plan.