Pressure booster pump

[rottenray6402]

I bought a cottage about a year ago and have been remodeling and rebuilding the place ever since. One of the problems is extreme low water pressure. This place is in a recreatioal area and is hooked to city water and all of my neighbors have the low water pressure thing also. I bought a booster pump from Northern Hydraulics which works really well with one exception. After the pump shuts itself off soon you can hear a hissing from the hot water tank. If let alone it will often build up steam and burp a small amount of water out of the pressure relief valve. To eliminate this happening all I have to do is open the hot and cold water at any faucet and you can hear air bubbling out of the hot water tank and then there is no problem. I replaced the relief valve with no change in symtoms.Has anyone out there had experience with these pumps? Due to space constraints I had to mount the pump above the hot water tank but there was nothing in the installation directions warning against that. It is obviously aerating the water into the tank and I wondered if anyone knew of a cure for this.

 

[Boomyal]

Re: Pressure booster pump

Without knowing anything about the pump you got, it is hard to say. There could be several variables but a pump should not be aerating the water for starters. At minimum you may need to put a little plumbing surge tank on the inlet line to the hotwater heater. In many areas that is now code anyway.<br /><br />What is the static line pressure and what range is the pump set to turn on and off? And did you install a spring check valve between the street and the pump?

 

[rottenray6402]

Re: Pressure booster pump

The pump's range is 35 to 50lbs boost above existing water pressure. I have it set on 40 right now. I haven't measured the existing pressure with a guage but I would guesstimate about 20lbs. No I didn't put in a spring check valve. Is that like a one way valve? The surge tank sounds like it may be what I need. I put a stand pipe about 2ft long in the system below the pump but it made no difference. Would it make any differnce that the line coming into the house is 1/2 copper and I plumbed the inlet with 3/4 in anticipation of redoing the inlet someday? This is an old cottage area where the originals probably didn't even have plumbing. Thanks for your help. I'm leaving for out of town so will check Monday for any replies.

 

[JB]

Re: Pressure booster pump

Booster pumps should require a pressure tank, Ray, just like a well pump. You don't say if you have one. What you seem to have is a hot water tank acting as a surge tank.

 

[Boomyal]

Re: Pressure booster pump

Originally posted by JB:<br /> Booster pumps should require a pressure tank, Ray, just like a well pump. You don't say if you have one. What you seem to have is a hot water tank acting as a surge tank.

JB, some 'booster pumps' are made to operate without a traditional pressure tank. That is why I mentioned that there could be 'variables'. All that being said, you are correct in the assumption that the hotwater heater is trying to act like a surge tank. What I do not understand is why he is getting air unless the pump is cavitating while it is trying to 'overdraw' from the low pressure or restricted supply line.<br /><br />Without knowing the specifics ie, pump type and capabilities, it would be hard to give good, sound answers.

 

[rottenray6402]

Re: Pressure booster pump

Thank you both for your replies and possible solutions to this problem. I am going to try the surge tank to begin with as it certainly makes sense that the hot water tank itself is acting as a surge tank. My other question was as Boomya said about areation due to trying to overdraw the 1/2 inch line. I will post again when I get it taken care of, once again I really appreciate the help.

 

[POINTER94]

Re: Pressure booster pump

Ray,<br /><br />shooting a guess, I would have to say that your pump is probably cavitating (boiling the water)and creating air which may be getting trapped in your pressure relief. Your upsizing of the pipe can only help as it will reduce the velocity the water is traveling. You can boil water at room temp if your pump is creating a suitable vaccum. The other option is you might have a small pin hole on the suction line and it is drawing air threw it. Try wrapping the new suction line and fittings with saran wrap and run a few cycles. This will cover any small holes temporarily and cutting it away until you recreate the condition. You found your leak!!!<br /><br />A pressure tank will decrease the number of cycles the pump will experience in the course of a day and extend the life of the pump. A pump is like a car, all/most the damage is at the start. Most pumps lives can be measured in cycles not years. And duty cycle on some of the ODP motors can be as long as 6 minutes. It will also limit the amount of water hammer you can or might experience. Use sweeping 90's or better yet two 45 degree elbows. And always have at least 4 times the diameter of the pipe going into the intake on a straight line. No quick 90s on the inlet. <br /><br />Make sure you are using a solid check valve on the line into the pump or you will be pressurizing the entire neighborhood. If the pump has a built in check they usually suck. Usually a cheap plastic spring loaded with a poor seal.<br /><br />Knowing what model pump you have would be of great assistance. I can't imagine you would need anything larger than a 1/2 hp. Anything larger will result in a shortened life of the pump. Bigger is not better in the world of pumps. In fact they are worse.<br /><br />Mounting above the water heater is not a big deal as long as it doesn't leak and your plumbing isn't a speghetti dinner. Most water heaters don't emit enough heat to trip the thermal overloads in the motor. If the motor shuts off unexpectedly it is frequently the termal overloads in the motor. Get a gauge on the system so you know where you are operating. Without it you are kind of fishing in the dark.<br /><br />Be careful with old pipes, they don't like change especially quick change. Increase system pressure about 5lbs a week until you reach your desired operating pressure. This may help prevent your old pipes from blowing out unexpectedly.

 

[rottenray6402]

Re: Pressure booster pump

Wow Pointer, you have just increased my knowlege of pumps by about 10 fold. I will try these suggestions. When I re-did the plumbing I replaced everything on the supply side with copper so I should be good as far as pressure goes. I will get make, model, and hp of the pump to post. I have the pump on a switch and only run it during showers and laundry. It runs all of the time the water is on rather than cycling like a well pump will do and then shuts off about 15 seconds after the water is shut off. I believe that everyone here that has replied is correct in the fact it is areating the water to the tank. I did not use a check valve so I am going to install a check valve and the small surge tank and see if that helps. Once again, thanks to everyone for your suggestions!

 

[Boomyal]

Re: Pressure booster pump

If you are not using a large 40, 60 or 80 gal pressure tank in conjunction with the pump, you better have chosen a booster pump that was made to operate without one. You also need to make sure that the HP/GPH rating are/is not larger than the available water supply.<br /><br />A hot water heater inlet surge tank may help matters but if the above were not taken into account, it would only be a bandaid, at best.<br /><br />In addition you should not have to have a boosted water supply that you have to manually turn the pump on and off for.

 

[SS MAYFLOAT]

Re: Pressure booster pump

Yep on what Boomyal said. If you can't supply the pump with water, it is going to cavitate creating air. That is what the tank is for. If you use up the capacity of the tank you choose, you will then experience the air again.<br /><br />The longer you need to draw water, the bigger the tank you will need. Washing machine, baths, showers, and dishwashers are your main users. Also don't forget if you use muffs on your boat motor, it also can use up a lot of water.<br /><br />Using water savers/restrictors can possibly remedy your situation and allow use of a smaller tank.<br />Good Luck

 

[POINTER94]

Re: Pressure booster pump

Ray,<br /><br />Just a couple more points, the tank should have a drawdown equal to the gpm of the pump. If the pump is designed for around 10gpm then you need to get a 10 gallon drawdown tank. In this case a 35gallon tank or what is known as an 82gallon EQUIVALENT tank. (two ways to say the same thing) The manufacturers of the tanks don't have a standard size chart/nomenclature. If this is a cottage don't go to crazy in oversizing the tank although bigger is better. As the water will sit in the tank between your visits and get stale.<br /><br />I would also turn on the pump and leave it on. Most pumps are designed for a minimum of 250,000 cycles. Thats quite a few years. Our old cabin up north has a jet pump on it from the 60's. They hold up pretty well.<br /><br />Hope this helps.

 

[rottenray6402]

Re: Pressure booster pump

Once again thank you all for your help. I looked briefly at the pump last night and it is a Flowtec 3/4 HP booster pump with an attached plastic box on top with the pressure regulator dial. I bought it from Northern Hydraulics and this is the only pump I have ever seen adverised as a pressure booster. I will get GPM and other info tonight.

 

[POINTER94]

Re: Pressure booster pump

Well Ray,<br /><br />You picked the best pump I know. I think that has a stainless body with a smaller like motor with vents all around it. Some may call it a watts motor because they are rated in watts and I believe they are made in Italy. It is incredibly quiet and it is very efficient in terms of power consumption for the horsepower. This thing will pressurize to whatever pressure you would like in your application. That is a multistage pressure booster pump. The only weakness of this pump is the box on the top. It doesn't work very well. Try adjusting it and I think you will find it does very little. If the box ever leaks, just remove it as it is only screwed into the top and plumb it straight in. Add a 10 dollar pressure switch and you will have more accurate and adustable pressure control. If you add a tank it will help smooth it out and add to the lifespan. In fact I believe it uses a TEFC (totally enclosed fan cooled motor) so mounting it upsidedown or sideways or anyway won't matter one bit to this motor. It is actually made by a company in Italy called Nochi but sold under the Flotec label. Power branding.<br /><br />Great selection. I think you will be very happy.

 

[rottenray6402]

Re: Pressure booster pump

Thanks Pointer, it was just luck on my part that I got a good brand. As you have probably surmised by my posts that pressure booster pumps are not my strong area! I intend to try the tank as soon as possible and see if that eliminates the cavitation. One other question if I may: You mentioned several posts back that without a check valve I may be pressurizing the neighborhood. Since there is suction on the intake and pressure on the out flow this wouldn't pressurize anything but my system inside the cottage would it? Or are you talking about when the pump cycles off and the system is still pressurized it has equal pressure on the intake side also? I'm sorry to be dense but I am the kind of person that tries to understand how everything works together. As always, thanks for the help!

 

[Boomyal]

Re: Pressure booster pump

RR, if you had that pump hooked up to a pressure tank and just let it operate automatically via the switch setting you would see the following on a pressure guage without a checkvalve.<br /><br />Pump runs to pressure and shuts off. Guage drops to pump cut in and it just continues to cycle repeatedly. The pressure will bleed back thru the pump and try to equalize with the incoming line pressure.

 

[POINTER94]

Re: Pressure booster pump

I am being a little disingenuious. My company manufacturers that pump. (1 of about 5000 different pumps) And unless you run greater than about 8 gpm this unit will cavitate. I also used this exact pump in my brothers home as he has low pressure and as I can have any pump I want I still chose this one. I modified it as outlined above.<br /><br />For about 90 bucks you can get a nice little 6gpm drawdown tank at any home depot or menards. Not having the check valve will allow the water pressure to flow back into the main and if the difference is great enough, make the impellers run backwards which could damage the unit, not likely but possible.

 

[rottenray6402]

Re: Pressure booster pump

Thanks Pointer and Boomya, I was thinking about when the pump was running but it makes perfect sense when the pump is off for the pressure to bleed back into the inlet since that pressure is so much lower than the boosted pressure. I am going to get a check valve and a tank for the system. I will let you know how it all comes out. It may be a month or so before I do that because I just got my new (to me) Crestliner 196 Eagle and it needs a lot of cosmetic tinkering before serious boating / fishing. Thanks guys! By the way Pointer confession is good for the soul but you never really fibbed, you just omitted some information! No harm done.