developing a spring/ water hammer

uarelovedbygod · #1 06/28/05, 08:55 PM

OK, I ran out of water last week..rainwater cistern. Works good in the rainy season, but....

So I found a spring to develop. Despite the dry weather here in KY, it is putting out about 3/4gallon per minute. It is about 180 feet above ground level. I am running a 1 inch black pipe from the spring to a 325 gallon holding tank about 110 feet of elevation. I plan to run a 1.25 inch line from the tank to the house, and hook up with the plumbing between my jet pump and 36 gallon pressure tank.

A dear friend was concerned that I might have a problem with sudden surges in pipe pressure inside my house due to a water hammer effect. He suggested putting in an air column with 4 inch PVC pipe or putting in pressure release valves outside the house. Is this necessary, or will the air bladder in the pressure tank act as an air column?

Thanks.

agmantoo · #2 06/28/05, 09:00 PM

Your storage tank on the jet pump will buffer the pressure from the well cycling. With the pressure switch on the jet pump set on a 20/40 or 30/50 for the on/off range I doubt that you will have a problem. Water hammer is typically brought about by an inrush of high pressure water such as one may have on a city water system.

uarelovedbygod · #3 06/28/05, 09:06 PM

agmantoo,

I don't plan to put the spring water in the cistern. I plan to hook it up to my existing plumbing and turn the jet pump off. I should have 50-60 psi of water pressure with gravity feed without needing to use electricity. My concern using gravity feed is the inertia of the water coming down from the holding tank 110 feet up. Does the inertia of the water increase the severity of water hammer effect?

boxwoods · #4 06/28/05, 09:11 PM

If you can, you should put the tank close to the spring feed, and you might have enough pressure without a pump and tank at 110 feet. Try it first! use overflow a tad below feed to tank. bury the one inch from near bottom of tank to house below frost level. That way the tank won't freeze because of moving water. Spring was a good find if it will produce that flow year round.

agmantoo · #5 06/28/05, 09:19 PM

I am sure you have your reasons for connecting in the manner you described but that is not how I would do it for the following reasons. At 3/4 gallons per minute that is not much of a supply. Showers are going to be a problem with the low delivery. It will take a long time for the washing machine to fill, roughly an hour for a wash and 2 rinses. The gravity water going to the cistern would let any debris settle and it would permit you to have a reserve. The cost to run the pump is minimal and obviously you already have electricity. I suggest you rethink your change.

uarelovedbygod · #6 06/28/05, 10:09 PM

Agmantoo,

I think this setup will work. At 3/4 gallon per minute from the spring I should get up to 1000 gallons per 24 hour period. Yes that is a slow spring, but it is the dry season and I think it will pick up in the fall and winter. The line from the spring goes into a 325 gallon holding tank, which is 110 ft above the house. Water will only leave the tank if it fills up ( overflow pipe to the pasture/pond) or if I turn a faucet on in the house. I should only need all 325 gallons to fight a fire or fill up a pool. So there will always be some in the holding tank, and the flow to my house should never be 3/4 gallon per minute.
--Chris

fernando · #7 06/29/05, 05:15 PM

bump - advice needed -

Orville · #8 06/29/05, 10:34 PM

I'm no expert in this area, but I know plumbing with wells and pressure tanks can have the water-hammer effect. I have seen, in such homes, a piece of pipe sticking up perpendicular to the line, and have been told it is to modify the hammer effect.

LittleJohn · #9 06/29/05, 10:46 PM

3/4 gallon a min is plenty for all but a car wash or dairy farm. Just wont give you a lot for your garden thats what takes a lot of water. But I realy dont see why you need a pump with 110' of head? I doubt our spring puts out any more than that mid summer and its plenty for a fairly large house. But like I said its not enough to water a garden. Though it might be if you had a larger tank. Remember it runs 24/7.
Unfortunately ours is below the house and garden so we did need a pump.

BobK · #10 06/29/05, 10:57 PM

Water hammer can be a problem but one that is easily dealt with. It basically comes from the sudden cessation of flow....if you turn the valves in the house off quickly you'll get water hammer...if you turn them off slow no problem. '

The amount of water you are talking is huge.....but you need a tank big enough to catch it for use. We have a homestead that runs off of less than 1/2 gal per minute and we have a very alrge garden, orchard, animals, and the house. Only problem comes if a faucet gets left on in the garden and the tank drains. But this is only temporary. If your really worried about the water hammer reduce the size of the line to the house which will decrease flow and the magnitude of the hammer.

One thing on the spring I know people who have tried to dig a spring out to improve flow and have lost the spring....if it were me I would use the minimum to clean out the spring and put in a small spring box.

uarelovedbygod · #11 06/30/05, 06:36 AM

Thanks BobK,

I think I will reduce the pipe to 1 inch..considered 3/4 inch but I am not sure that can supply all the demand I may have with the house, farm animals, garden, etc.

I have been told that a washing machine causes the most water hammer problems, as it demands a large flow of water and the internal valves shut off quickly when it is done filling up.

BobK · #12 06/30/05, 09:48 AM

For the washing machine you can attach a air damper right at the faucet which wll minimize the hammer. All it is is a section of pipe capped and attached vertically so a air head space is held there to dampen the hammer. It (the hammer) probably won't be that bad since most faucets are limited to 3/8 inch diameter outlet. If you have a gate valve at the washer you might want to change to a water spigot or faucet.