We have one well feeding a house and a church building. The pressure tank is in the basement of the house. It is then piped to the church. When a toilet in the church is flushed, the pressure in the second floor bathroom of the house drops to near zero. Can we install a second pressure tank in the house basement for the church? If not, how can we solve the problem without digging another well?

Describe you piping. It is most likely that the piping to the church is tied into the piping to the second floor and the piping between that point and the tank is under sized.

I would add a large pressure tank in the church itself. This should take care of your problem. Good luck and please let us know what you think. Lee.

To hkstroud, piping: From the well, 103 feet to house, 33 feet across basenent to pressure tank, to an ultra violet sterilizer, to a water softener, then one pipe to the rest of the house and one pipe 75 feet to the church building. The pressure tank is a Well Mate model WM14-WB, max operating pressure 125 psi, factory precharge 40 psig. A local plumber said we could not put a second pressure tank in the basement for the church building, but I couldn't understand his explanation of why.

Thwe plumber was concerned that you had combiuned the two systems.
Where you made your mistake was in not taking the church supply off before the house. I would move the church supply back before the house supply and install a check valve just upstream from it to isolate the house. Now your house is a closed system and you can treat the church as a new installation complete with check valve and bladder tank.
Bet your plumber likes this configuration better. Good luck, Tom

What is the pipe size between the tank and the point where the church is tied in, what is the house pipe size after that point and what is the pipe size to the church. Either the pipe to the split is inadequate or the water softener or the sterilizer is creating a flow restriction. Suggest bypassing the water softener just to see what happens. Do you need the water softener and sterilizer for the church? I see no reason why you couldn't have a second tank at the church. An additional tank at the church with a check valve should act just like a separate well and tank.

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An additional tank at the church with a check valve should act just like a separate well and tank.

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True that Herold! But only if it's taken off before the house system. Otherwise you'll be combining two systems and that's what the plumber was complaining about. To do it any other way would be making the house and church one system. Look at it this way. Leave the church supply the way it is and you're supplying the church from the house. Move the supply ahead of the house takeoff and you're supplying from the pump. Make better sense now? Tom

If he splits off to the church before the house, he will have to add another ultraviolet unit at the church, won't he?

Why not go: well to house to ultraviolet unit, then split to the house and church and put a tank/check valve in each location. The two systems would be separate from each other but still benefit from the sterilizer.

The problem I see with two tank/check valve setups is setting up the switch to the pump. Which tank pressure is going to turn the pump off/on? Can two switches be used for one pump?

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Why not go: well to house to ultraviolet unit, then split to the house and church and put a tank/check valve in each location. The two systems would be separate from each other but still benefit from the sterilizer.

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Works for me! But you're piling on a lot of labor and hassle. Did you read where le laid out the placement of the ultraviolet unit? What was that necessary for again? Tom

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Originally Posted by Waterboy05

To hkstroud, piping: From the well, 103 feet to house, 33 feet across basenent to pressure tank, to an ultra violet sterilizer, to a water softener, then one pipe to the rest of the house and one pipe 75 feet to the church building. The pressure tank is a Well Mate model WM14-WB, max operating pressure 125 psi, factory precharge 40 psig. A local plumber said we could not put a second pressure tank in the basement for the church building, but I couldn't understand his explaination of why.

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Cavitation in the line between the two is the reason why.

The drop in pressure could likely be reduced if you installed a booster pump at the main line coming into the last leg of the system.

OK, what wrong with my logic?

Well pump supplies house tank. House tank supplies church tank and house. Pump runs until house tank reaches cut off. At that time both tanks are at cut off pressure. Water usage in the house does not affect church tank because of check valve.

Water usage in the church does not affect house unless church tank pressure drops below house tank pressure. Because of the presumably greater usage in the house and the cycling of the pump to replenish the house tank, the church tank will be at pump cut off pressure a good percentage of the time. When and if church tank drops below the house tank pressure there will of course be a flow from the house to the church, but that flow would be at a minimum because of the small pressure differential between the two tanks. Should there be a demand for water at the house as the two tank pressures are equalizing the reduction in flow to the house would be at a minimum.

Where did I miss the gate here.

Rereading Waterboy's post, note that he said this occurs on the second floor bath, didn't say entire house.

Think we should have asked at what pressures he is operating and what the size of the tank is.

Also should ask, does this happen all the time or just when tank is at or near cut in pressure or when operating on pump pressure only. Could be that he only needs a higher cut in pressure to minimize occurrence.

SB, he said: "piping: From the well, 103 feet to house, 33 feet across basenent to pressure tank, to an ultra violet sterilizer, to a water softener, then one pipe to the rest of the house and one pipe 75 feet to the church building."

You then suggested: "Where you made your mistake was in not taking the church supply off before the house. I would move the church supply back before the house supply and install a check valve just upstream from it to isolate the house."

So, if the UV unit is after the pressure tank, and you tell him to come off the main line (to go to the church) BEFORE it gets to the house, then how is the UV unit going to treat the water going to the church?

Harold, you asked why this wouldn't work

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Well pump supplies house tank. House tank supplies church tank and house.

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That's why. Two bladder tanks on one system. Widdershins addressed that in a earlier postand the plumber refused to install it that way. You're insisting on making this one system and that's not going to fly.

Ron, If you're determined to include the house UV unit in the church system then you'll have to reconfigure the house system since both the UV and the softener are upstream from the house bladder tank. Both of you guys seem determined to combine the two systems and that's what got the nplunber uptightin the first place.
If you took off the church just upstream from the UV unit as you indicate the we would be back to two bladder tanks on the church line. About the only wayto use the UV unit for both ssystems would be to move the UV unit back downstream from the two check valves and just upstream from the pump. That way by having the pump and the UV unit ahead of where the two systems separated ,and they're going to hafta be separate to operate correctly, the pump would supply pressure and volume along with UV protection. Regards, Tom

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Originally Posted by hkstroud

Rereading Waterboy's post, note that he said this occurs on the second floor bath, didn't say entire house.

Think we should have asked at what pressures he is operating and what the size of the tank is.

Also should ask, does this happen all the time or just when tank is at or near cut in pressure or when operating on pump pressure only. Could be that he only needs a higher cut in pressure to minimize occurrence.

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I agree 100% Harold. Great thinking. Maybe we should be looking at simple solutions to this instead of redesigning the complete layout. Upping cut in pressure(and or cut out pressure) or installing a larger pressure tank may be just what the doctor ordered.

What am I missing here guys? Ya-all seem to think that leaving the church takeoff ahead of everything else would be just peachy keen if only you installed a check valve. That's not going to fly. The plumber refused to install a bladdrer tank in the church, Growler gave you the reason for it and what else do you need? The way it's set up now the church is being supplied by the house. I want to move it down to where the church is supplied by the pump. And use check valves to isolate the two systems. Why am I getting all this feed back? If I've made a bad call about this and my reasoning's faulty then someone please tell me where I went wrong. Tom

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Originally Posted by speedball1

What am I missing here guys? Ya-all seem to think that leaving the church takeoff ahead of everything else would be just peachy keen if only you installed a check valve. That's not gonna fly. The plumber refused to install a bladdrer tank in the church, Growler gave you the reason for it and what else do you need? The way it's set up now the church is being supplied by the house. I want to move it down to where the church is supplied by the pump. and use check valves to isolate the two systems. Why am I getting all this feed back? If I've made a bad call about this and my reasoning's faulty then someone please tell me where I went wrong. Tom

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I've pulled out and replaced well pumps that had the impellers blown right out of 'em from the shock of the water bouncing back and forth between two bladder tanks -- You also can find bits and pieces of the swing gates from check valves lodged in the well pump or the seat of gate valves -- Once the water starts bouncing back and forth, there isn't anything to stop it from picking up further momentum until something is opened up or something bursts.
Thanks Steve.

Not trying to be argumentative, but for the sake of clarity:

1. How can pressure bounce between two tanks that are separated by two checkvalves?

2. What difference does it make where you branch off to the church/house? One way or the other, the two systems are still going to be connected.

3. Since the system is presently: well... tank... UV unit... split to house/church, then why not simply put a tank in the church with a check valve to prevent water from flowing backwards? That would seem to be a fairly inexpensive and simple solution.

4. My big question, still unanswered: How do you control two pressure tanks, separated from each other by check valves, and only one pump? Can this be done with two switches?

I know that's a lot of questions. Ignore them if you'd like to, but I'd really like to know about #4. However, if the UV unit is really needed, then SB's solution would call for a second unit at the church. Again, not trying to provoke anything, but the homeowner would need to be aware of that.

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Originally Posted by jlisenbe

Not trying to be argumentative, but for the sake of clarity:

1. How can pressure bounce between two tanks that are separated by two checkvalves?

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The check valves would never actually be closed -- The ping-ponging effect would leave the gate of the check valves fluttering back and forth, most often in a partially open position.

If this were a system I was designing, I would put a storage tank with a ballcock assembly and booster tank in one or the other of the dwellings and remove it from the pressure tank.

First, my question of "What's wrong with my logic" was a real question. Not arguing for a position. While I've had some exposure and experience to well systems I'm certainly not in a position to argue about anything. While my logic makes sense to me (but then it always does, no matter how wrong I am), I realize that there is too much I don't know. Therefore I was really was asking where am I wrong, what am I missing.

With all that in mind, I'd like to ask another question. I'm not being argumentative here. While I can grasp the idea of cavitation, back pressures, reactions to pressures changes, pump surges, I don't know under what circumstances they occur.

So here goes the question. I can see how cavitation could occur, due to pump surges, if the pump is feeding two tanks . Two tanks shall we say in parallel. But do you have that problem if the tanks are in a series? One tank feeding the other. It seem to me that two tank in a series would act like one larger tank for the most part.

Remember it is a question, and only a question. Also, keep in mind that I only have one brain cell and its showing it's mileage.

For the sake of discussion, as to Ron's question about pump control. A pressure switch on the first tank, since its pressure would always be less than or equal to the second tank, assuming a check valve. Without a check valve with positive seal the tanks would always have equal pressure.

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Originally Posted by hkstroud

So here goes the question. I can see how cavitation could occur, due to pump surges, if the pump is feeding two tanks . Two tanks shall we say in parallel. But do you have that problem if the tanks are in a series? One tank feeding the other. It seem to me that two tank in a series would act like one larger tank for the most part.

Remember it is question, only a question. Also, keep in mind that I only have one brain cell and its showing it's mileage.

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We are talking about bladder tanks, right?

Two pressurized bladder tanks will always be fighting for supremacy, even a 1/2 pound difference in pre-charge can start a ping-ponging cascade.