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I know it's a carry over from city life, but I hate the low water pressure we have. The pressure tank works at 30/50. I checked the bladder; it's fine. The pump delivers enough volume when the tank calls for it that the pressure shoots back up to 50 pounds in about 10 seconds. Since it delivers that kind of volume, why can't I find a pressure tank that would give me the higher water pressure I prefer?
Is it a time honored tradition that the those things would burn up the pump?
Don't you have an adjustable pressure switch, that you can re-set to the low-high pressure that you want? Mine is that way, and I go 40-60, or thereabouts.
The tank has nothing to do with it is the switch. Home Depot Ace hardware, Sears all sell 40-60 switches that can be set higher if you desire. But 10 seconds is a fast fill. Either you have a small pressure tank or I suspect that it is water logged and does not have enough air in it. A 50 gallon bladder tank should take about 35 gallons to fill I can.t believe you are pumping even half of that in 10 seconds.
Hi,
I think I can help with your question. As mentioned, it's the pressure switch, not the tank, that determines your hi/lo pressure. These switches are typically factory set at 30/50.
Why not 60/80? Well, like most things in life, there are trade-offs. In short, you'd have to get a much larger bladder tank (or be prepared to replace your pump every few years). Also, at 80 lbs cut-off, you'd risk damaging fixtures with flexible tubing and/or pumps (e.g., icemaker, dishwasher, clothes washer, toilets). Having said that, one can usually get away with 40/60, depending on the relative size of the tank vs. the pump discharge rate (based on your 10-second run-time, either your tank is bad or the installer didn't know what he was doing).
The most common pressure switch has two spring-loaded adjustment screws (if not, you can buy one for under $20). One controls the cut-out pressure setting while the other controls the pressure differential. (NOTE: BE SURE TO KILL THE POWER BEFORE MAKING THESE ADJUSTMENTS!!!). There should be a diagram inside the lid that shows which screw is which. Leave the differential set at 20 psi. Even still, you need to check the pump run-time to make sure you aren't short-cycling the pump. Here's why: the tank's usable volume will actually be lower at 40/60 than at 30/50. This in turn decreases run-time, which will shorten the life of your pump.
The installer is supposed to choose a bladder tank large enough to keep your pump on for at least two minutes as it fills from 30 psi to 50 psi (most folks consider one minute adequate for pumps less than 3/4 hp). Tank manufacturers provide charts to help the installer choose the correct tank. These charts are based on the tank's "usable capacity". In case you're curious, the general formula for usable capacity is:
tank total volume * (1-((cut-in + 14.7)/(cut-out + 14.7)))
But in order to calculate run-time, one must also know the pump discharge rate, which depends on the particular pump's performance curve vs. the depth of the water table (not the depth of the pump). With this information, run-time is simply the tank's usable volume (gal) at given pressure setting divided by the pump discharge rate (gpm).
Even at 40/60, the pressure drop will still be obvious to most folks, especially during a shower (though not as bad as at 30/50 lbs). One thing I did in my previous home was to drill out the water restrictor in my shower head. I also tried a few several shower heads until I found one that seemed to work best.
Theoretically, you could set your pressure switch at 50/65, but you'd need a larger tank to maintain the minimum run time, especially if you have a big pump.
In my new home, I installed a variable speed pump designed to be short cycled (Emerald Elite by Myers). The electronic controller has a built-in differential of just 2 psi! I set the overall pressure at 57 psi so the cut-in is 55 psi. This is also known as a constant-pressure pump. It starts gradually, and builds up speed over a few seconds, until shut-off. Unless I'm irrigating, it never runs more than four or five seconds at a time and therefore doesn't achieve full speed. The EE is very pricey (over $1k?), but IMHO, worth the money. BTW, it shouldn't require a bladder tank (at least, in theory), but you have to have a small one to offset the lag in the system. Other than the price, the only disadvantage is that it has very low torque (naturally, due to slow-start design), so it's more susceptible being damaged by sediment. I was a beta-tester for this pump and burned out the first two until the distributor figured out that fine particles were being ingested, causing the pump to lock up. They installed a fine sediment filter and it's been operating perfectly ever since (4 years now).
DB
That was very helpful pressure information, from many aspects (especially the "disconnect the power" safety reminder). Thanks for taking the time.
There are pumps sold already set up with pressure switches etc expressly for "boosting" low water pressure. Even Harbor Freight sells them. Look at the on-line catalog.
www.harborfreight.com
[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]
Thanks for all the suggestions. We got relief in a way one wouldn't expect.
The whole house filter casing on our 3/4 inch line broke.
Since I then needed to replace the filter, I looked into a larger filter that used a 1 inch line from the pressure tank to the filter. The guys at Home Depot assured me that 3/4 inch should be adequate, but it only required $2.00 worth of new pipe to put 1 inch to the filter.
Coming out of the filter we step down to half inch, because I am not yet ready to re-plumb the whole house.
Nevertheless, this one seemingly minor change "doubled" the perceived pressure at the shower head. Even with the tub and toilet running at the same time, we have plenty of pressure.
Who'd a thunk it? [img]/forums/images/icons/grin.gif[/img]
It is very unlikely indeed that the change from 3/4 to 1 inch for that short of a run was the answer. Much more likely is the new filter is not nearly so restrictive to the flow. The old filter was probably either plugged up with fine materials or possibly was just too fine and restrictive.
Most importantly, for whatever reason, you get a good shower now!
[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]
I'm familiar with the Simer booster pump you mentioned (Harbor Freight item #9670). It has an input limit switch at 45psi, so the bladder tank must be set to 20/40. This will yield a house-side pressure of approx. 60/80. It requires a 1" hook-up line and a check-valve. They're about $400 installed.
Perhaps a less expensive option would be to add another bladder tank in series. This will increase the usable capacity allowing you to either increase pump run time or increase tank pressure (and/or reduce the differential).
BTW, as a followup to my previous post, one should never set differential to more than 20psi (e.g., to increase pump run time) unless the tank is designed for that. This will fatigue the bladder and void the tank warranty.
DB
Which would work better?
A super large pressure tank (or two in series)
or one of those harbor freight "booster pumps"
I really would like to have BIG water pressure in the new house. We currently have a point for a well, I have a large bladder tank.. but it's still minimal pressure.
Thanks
JP
Actually there is no good reason I can think of for putting 2 or more bladder tanks in series. Placing the tanks in series may cause the pump to repetitively short cyle. Placing them in parallel will work OK. I got quite a lecture on this topic from an engineer at a sumersible pump manufacturer when I was exploring alternatives for my well/water distribution system.
Placing tanks in series or parallel will not increase your pressure, just the volume you can draw before lowering the pressure to the pumps cut in pressure. A booster pump will increase your pressure IF it doesn't, over time, outrun your well's production rate. If you don't have a problem supplying the volume you are interested in but just need more pressure then the booster pupm is a good choice.
[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]
One possible reason not to have 2 or more tanks is pump run time. It would have to run longer and may not be designed for lengthy running.
Harry K
Ok.. so it sounds like a resonable size tank would keep a good volume of water (assuming my drilled well comes in with a good amount of GPM)
But it seems like 4 hundred bucks would be well spent at harbor freight to boost up from 40 to 60psi.. to up around 60 to 80.
Not quite "hotel water pressure" (I travel a lot and a REAL good shower at a high quality hotel is one of the few things I wish I had at home) but as close as I will get.
JP
With submersible pumps there isn't much of a heating problem and in general long run times with a big tank are easier on the pump that lots of short runs. The number of starts is important to pump life as a start is as wearing as a considrable run. Even with small tanks, water usage at a fairly high rate over a protracted time results in a long pump run unless the pump has an extremelly high GPM rating.
[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]
I think you are already know this and are planning on it, but you really need 3/4" lines feeding the 1/2" lines that run to individual faucets, etc.
You should have a pressure stem on your tank, you might check that the pressure in the tank is set about 2 pounds less than the pump cut in pressure. So if your pump turns on at 30 psi, your tank needs to be at 28 psi.
If your tank is filling back up in 10 seconds or less, it sounds like there is not enough pressure in the tank, or the tank is way undersized.
Dear Mystic Coke, [img]/forums/images/icons/laugh.gif[/img] I am surprised that none of the readers and posters to this informative thread have commented on the very short "fill" time that you have listed in your initial post. [img]/forums/images/icons/shocked.gif[/img] TEN SECONDS is way too short for a normal pump-up time, [img]/forums/images/icons/tongue.gif[/img] and one of two things is wrong: the tank air charge is not correct, [img]/forums/images/icons/frown.gif[/img] or the tank is hopelessly undersized. [img]/forums/images/icons/mad.gif[/img] Good pressure and delivery depends on the HYDRO-PNEUMATIC aspect of the water system being perfectly designed. [img]/forums/images/icons/tongue.gif[/img] It sounds like you have the HYDRO part right; with good pumping volume and head; but the PNEUMATIC part isn't working for you. [img]/forums/images/icons/crazy.gif[/img] SOMEHOW you need to increase the "squish" area in your system, by adjusting the air volume in the bladder tank or adding a second tank. [img]/forums/images/icons/tongue.gif[/img] Machinery is nice to look at, and machinery WILL overcome some of the problems associated with low delivery pressures, [img]/forums/images/icons/smirk.gif[/img] but there is actually no substitute for a BIG FAT tank. [img]/forums/images/icons/crazy.gif[/img]
I think you are right on (but it was mentioned a couple times, the first being the 3rd poster and once later). Hope it was resolved without too much expense buying additional equipment. [img]/forums/images/icons/wink.gif[/img]
Beenthere is correct. It has been mentioned several times not including yours. I do agree that the more or larger pressure tank(s) you have the better. As mentioned, be sure your "precharge" pressure is correct. Again, that is about 2 pounds under your cut in pressure which you can determine yourself with a pressure gauge. I find it easiest to turn the power off, open a faucet and go to the pump controls and listen for the click of the cut in relay. Note the pressure at that point. A small air compressor with a schrader fill valve is all thats needed, its the same you use to fill your tires. The importance of the precharge is to help in the longevity of the bladder.
PS How could you install pressure tanks in series? There is only one opening. I can only think of one way to install them and that is in parallel.