Required Pump Size with CSV

[Rory]

Hello,

Can one use any size pump with the CSV? The reason I ask is due to the fact that I have a 1 1/2 HP Sta-Rite jet pump  that has twice broken the PVC T-connector on the outlet side (a male pvc threaded connector goes into the pump and the T-connector is joined to the male connector). I used the T connector for a pressure gauge right on top of the pump outlet. I finally removed the T-connector and replaced with just a 90 degree elbow (also PVC) and I have had no issue since. While the pressure gauge was on I noticed that the pressure would be between 80 and 100 psi when the pump was on. This higher pressure makes me think the pump may be too large. Is this higher pressure normal?

The reason I got the 1 1/2 HP pump is that the pump has to push the water 23' above where it sits. With the possibility of having up to 7.5 gpm demand for showers (3 showers that have 2.5 gpm showerheads) I thought it best to get the 1 1/2 HP pump.

Thanks in advance for your response.

Rory

[Cary Austin]

The highest pressure Sta-Rite I can find is the model HMSF, and that only builds 73 PSI.  Your gauge maybe reading a little bit high.  Those plastic fittings are rated much higher than 100 PSI.  It is usually vibration or water hammer that breaks a fitting, not high pressure.  Yes the CSV can be used with any size pump, provided the CSV was sized to fit the pump.  That higher pressure on the inlet side is OK, and is how the CSV works.  The CSV makes the pump think it is in a deeper well or has farther to push when you don't need the full flow from the pump.  The CSV puts artificial head, (more backpressure) on the pump to reduce the volume of water when a small volume is all you are using.  That back pressure reduces the amp draw of the motor, making it run cooler, so it is actually good for the pump/motor.

[Rory]

Thanks for the response Cary.

In case it may shed some light, note that the pump I have is the CJ90F. I don't think the pressure gauge is reading high as it worked well on previous installation.  I thought the same thing about the vibration but it doesn't seem to vibrate at all. If anything there is pulsation which I think is normal but I wouldn't know. As to the water hammer, I hear nothing when the pump shuts off. Question, what do you mean by sizing the CSV to fit the pump?

I also have another issue I am unsure off. I have checked the time to for the pump to shut off after there is no water usage. The pump shuts off in about 20 seconds. From what I have read this shouldn't be the case. I have the pressure gauge set at 58/38 (due to an adjustment I made and left instead of setting it back to 60/40). The CSV is set at 50 PSI. Why would the tank be filling in just 20 seconds? Is this because the flow may be low and the tank is already filling even before the water pipes are completely turned off?

[Cary Austin]

OK I found the CJ90F.  Strange it isn’t in my old Sta-Rite catalog, and I couldn’t find it in the BEC program either.  Anyway the curve shows 80 PSI max, which you will see in front of the CSV when there is only 1 GPM being used.  There should not be any pulsing.  Makes me think you have a small suction leak.

You haven’t said which CSV or what size tank you have.  But the 20 seconds is how long it takes to top off the tank from 50 to 58 PSI while getting 1 GPM from the CSV. So I am guessing you have the 4.5 gallon size tank, which stores 1 gallon of water.  The tank is already half way full at 50 PSI, so it should take about another 30 seconds to fill from 50 to 60 PSI.  Stopping the pump at 58, is probably why you are only getting 20 seconds instead of 30.

There are all sizes of CSV’s.  You don’t want to put a 1-25 GPM CSV on a 50 GPM pump.  So the CSV should be sized correctly for the pump.

[Rory]

Thanks very much for the info. I appreciate the time you take to answer the questions on the forum.

I think the pump does reach its max when it's working. What I noticed was that the gauge's needle would bounce around when the pump was on. Does this mean there was vibration?

I don't know if I used the right term when I said pulsing, but what I mean is that if you hold the pipe you will feel some trembling. I thought this would be normal considering that a motor is on and water is moving through the pipes. The motion is nothing that you can actually see.

The valve and tank are the ones in the pside kick kit. I'll work on setting that pressure switch back to its original 40/60.

[Cary Austin]

You should have metal pipe and fittings (brass or SS) between the Pside-Kick and the pump, unless you have the Pside-Kick mounted to the wall.  The “rumbling” of the water flowing through the pipe is enough to break PVC pipe, when you have something heavy on both sides of the PVC pipe or fittings.  You can use the wall mount kit and mount the Pside-Kick kit to the wall, then you can plumb with PVC between the pump and the CSV/tank.

The gauge will flicker a little as water “rumbles” past in the pipe.  But if you use the restrictive orifice as circled in the picture, it takes out a lot of the flickering.  You can also go up to 45/65 or so of you want to increase the run time a bit.

[CamKrist]

Similar matter has already been discussed at yahoo answers. I can post the link if needed

[Cary Austin]

I would like to see that link please.

[Jack Austin]

I'm experiencing this same phenomenon with my new PK1A installation. 

I re-used an existing Flotec 4332 pump that had no pressure tank, so it only worked without constantly cycling (at 30/50 psi) with a precise number of sprinkler heads turned on.  This was inconvenient to say the least and useless for hand watering or anything else.  I mounted my Pside-Kick on the wall, tank hanging below and plumbed to the pump with PVC and removed the Flotec pressure switch completely.  Seems to work well so far in limited testing.

At low flows the pump gauge will often read up to 85 psi and when I shut off the sprinkler the pump will exceed 90 psi as the tank is filled.  The pressure switch will cut off the motor correctly and the two gauges will agree within a couple of psi that the system pressure is roughly 60 psi.  So I think the pump gauge is approximately correct.  I've never have the 75 psi relief valve open.

This sounds like normal operation but my concern is that I'm sort of dead heading the pump beyond its ratings.  I can't find anything in Flotec's documentation that confirms this, though, so I just don't know.

[Cary Austin]

The CSV1A valve cannot close completely, so it can never deadhead the pump.  The 90 PSI on the pump is normal.  With the pump shutting off at 60 PSI, that means there is 30 PSI differential across the CSV.  With 30 PSI differential across the non-closing CSV, that means you have a minimum flow of about ¾ of a GPM.  This is plenty to keep the pump cool, no deadheading.  I don’t usually leave a gauge on the pump side of the CSV, as that just seems to confuse people.  When you close off all the faucets, the pump builds up to 60 and shuts off, which means it is still moving enough water to stay cool.

Don’t sweat it.  Just enjoy the constant pressure and lack of pump cycling.

The relief valve needs to be installed after the CSV, and it need to pop open if the pressure ever get to about 75 PSI.