Booster pump after pressure tank

[tico007]

Hello,
New to this forum and new to wells, will try my best to explain. I live in Hudson, NH. All the houses in my area are on well water, most deep (100'+) My house has a monodrive (w/20gal pressure tank) installed 10+ years ago. 3k sf house w/2.5 baths, irrigation system on a half acre of grass. Pressure is a constant 65psi. All seemed ok until this year..

This was a bad year in the northeast, especially my area of southern NH. Severe drought like I've never experienced. Rained twice all summer. To this date we still have a rainfall deficit of almost 9". The grass was getting pretty bad so I added a cycle to the irrigation routine. Then it happened.. No water.. Lasted 5 mins. Then again the next day accompanied by what I guess you could call a hammering at a valve. We were running out of water.. Oh no!

I studied up on how that monodrive actually works. "replace this big tank with this tiny tank" all over the internet. Raving about constant pressure systems. Yes love that 65psi water, but further reading explains why you only need the tiny tank. Because its a cycle buffer, thats all it is. Using one of the constant pressure systems means no water storage (in my configuration). Completely well and pump reliant. Flush a toilet, get a glass of water, on comes the pump. This also means the 20 gal pressure tank that is there is basically useless. And after the threat of running out of water this setup needs to go.

What I want to do is..

- get rid of the monodrive
- go back to conventional 60/40 ps w/119gal pressure tank
- add something like this pic below on the house side to replicate existing 65psi
( https://www.amazon.com/DuraMAC-2HP-...e=UTF8&qid=1479818326&sr=8-1&keywords=DuraMAC )

The pressure reducing valve will mask the cycling of the large 60/40 pressure tank, simulating city water @30psi. Then the booster pump will bring pressure back to 65-70psi.

Is this setup possible? Please advise, thanks!

 

[Valveman]

You have always been and always will be "completly well and pump reliant". Pressure tanks don't magically supply water. Evan a huge 119 gallon size pressure tank only holds about 30 gallons of water. And that 30 gallons only gets in the tank when the well and pump supply it. All a pressure tank has ever been for is a "buffer" to keep the pump from cycling on/off too much while the well and pump are supplying water. When you have a constant pressure system to reduce the cycling, a pressure tank is almost a moot point.

However, you are correct that with the Monodrive system the 20 gallon tank is not supplying anymore water than a 1 gallon tank. The wider the difference in pressure betwween the pump starting and stopping the more water any size pressure tank can deliver BEFORE the pump has to start. The Monodrive system only has 1 PSI between on and off. That means the tank will supply basically nothing and the pump will have to start for every glass of water needed.

Constant pressure systems like the Cycle Stop Valve still use a regular 40/60 or in you case 55/75 PSI pressure switch setting. By having 20 PSI between on and off, a 4.5 gallon size tank can supply a gallon of water, a 20 gallon tank can deliver 5 gallons, and a 119 gallon tank could spit out 30 gallons before the pump starts. But make no mistake, you are still completely reliant on the well and pump for water, as even 30 gallons in a huge pressure tank won't go very far in a house that uses 300+ gallons every day.

Now having said that you have already gotten more than twice the average life out of that Monodrive. That is the point of any of the variable speed type constant pressure systems. Get great 65 PSI pressure for 5 years or so, then pay the Piper to get a new one to last another 5 years or so.

As you said, you had great pressure until recently. So 65 PSI is the pressure you need and want, so the system with the Burcam thing that only gives 30 PSI will not make you happy. Plus the Burcam is a flow off/pressure on "constant pressure" type system. These are also designed to give you constant pressure, use a small tank, and to be replaced along with your pump on a regular basis.

There are many devices on the market that are designed to give the same constant pressure performance as a Cycle Stop Valve, without making the pump last as long as it does with a CSV. Constant pressure is a good thing, but it is only good for the manufacturers if it doesn't also take all the cycling out of the system and make the pump last longer like a CSV does.

You need to firste determine if the well is really dry, which I doubt, or if the Monodrive is the problem. At least you have a single phase motor, so you can just go get a regular single phase control box. That will probably get the pump going again. If not, then you have a problem with the pump as well. But even if the well is dry, it will produce water for a minute or so if the pump is functioning as it should.

 

[Sponsor]

 

[tico007]

Thank you for the reply. Sorry if I'm not explaining correctly. Living in the city I took water for granted. Being on well water is a new experience. What I was attempting to explain was... this year the water pressure was good right up until there is no water at all. 65psi then boom nothing. No water. The monodrive error code says recovery mode.. (for 5 mins). The monodrive cuts power to the pump while the well recovers. So i was close to going dry, maybe catching air at the pump, don't know how the monodrive knows. Then after recovery pow! 65psi hammers the pipes. Whatever pump is installed is powerful.

Why this year? Partly a severe NE drought. The other is a well that likely has some buildup of minerals and has slowed. So i'm using water faster than the well can recover at peak times. The monodrive is working fine. I just don't have enough water for everything at peak hours. Not enough water in the well, does not recover fast enough. It used to. Short of replacing or repairing the well for a fortune I was thinking that pumping some reserve water off peak and having it on hand is better than going dry. that 30 gals of a 119gal pressure tank in reserve + whatever is in the well may get me through an irrigation cycle without losing all water. Protect me in a drought.

Does a CSV conserve water via pressure? I'm reading that similar to a monodrive the CSV eliminates the reserve tank of water. And what if I use a CSV in conjunction with a larger tank? Will i still get the benefits of 30 spare gals?

 

[ThirdGenPump]

30 gallons lasts about 2 minutes of an irrigation cycle. There is no easy fix for not enough water, you're just throwing good money after bad. Shorten your irrigation cycles and allow more time for recovery in between.

If your well is being impacted by drought it's not deep enough and you should seriously consider deepening it or drilling a new one. Or live without green grass and save your money.

 

[Valveman]

I am not sure you are running out of water. VFD's like the Monodrive are notorious for glitches. I would replace the Monodrive with a standard 3 wire control box to fit the horsepower of the pump you have. Then I would do a test on the well to see how much it can produce and for how long. The pump will produce a lot more water when running out a wide open pipe with no pressure against it. If it pumps the well dry running wide open, I would throttle it back with a valve and try running it at 40 PSI. If it still pumps dry hold back 50 PSI, then 60 PSI, and so on until the pump stays running and doesn't pump the well dry.

It could be that your zones are set up for 20 GPM, and the well is only making 19 GPM. This will cause the well to make air in short order. But if that is the case and you reset all your irrigation zones for less than 18 GPM, then you will not be pumping the well dry.

If the Monodrive is working properly it should vary the flow from the pump similar to the way a CSV does. So you can reset the zones to a smaller flow rate, and the Monodrive should keep the pump running continuously. If the Monodrive is the problem as I predict, then use the standard pump control box and a CSV to vary the flow to match the zones.

A well will not just go from making 20 GPM to Zero. It may drop from making 20 GPM to only making 18, 15, or a lesser amount. So when you figure out how much the well will produce the CSV will allow you to reduce the sprinkler zone sizes. That way the pump does not cycle on/off for the lower flow rate zones, and you can match the amount the sprinklers put out to the amount the well will produce.