I have two experienced plumbers telling me two very different things about my domestic well and water system -- settle the debate?

[Stan_N]

Hi there, I hope y'all can solve a debate, as I'm in the middle of an installation and getting two very different opinions from two experienced plumbers.

For some background, I'm on a well, and my system is below the frost line. To keep the pipe from freezing, I have Drain Back System, which includes an air over water tank with volume control, a drain back valve, and a snifter valve. The setup is very similar to this.

There was also once another pressure tank, a bladder tank, on the other side of the house, which broke a while ago.

This has been the setup since before I owned the house.

A few days ago, during a water softener install, the air over water tank broke, so we had to order a new one. The installation plumber insists that I also need a bladder tank in the same room, right after the air over water tank. I never had a bladder tank in that room before, just the one on the other side of the house that broke years ago. Another plumber, who has maintained my system for years, insists that we don't need another bladder tank and that the air over water tank with volume control is more than enough to manage the pressure and maintain a healthy water pump. They also have differing opinions on the setup.

So the two issues I need to resolve are:

1. Does a system with a air over water tank with volume control actually need a second pressure tank (like a bladder or diaphragm)? Or is the second tank overkill?
2. With the second tank installed, even if it is overkill, which one comes first in line? One plumber insists that the order is well ---> UT tank ---> bladder tank. The other plumber insists that the order is well --> bladder tank ---> UT tank. Which one is correct?

I'm hoping someone here can settle the debate, as I'm at a loss as to who to believe and how to move forward. I'm frankly fine with having two tanks, if it reduces load on the well, but I at least need to make sure they're installed in the right order.

 

[Reach4]

1. Normal is to not have the second tank. But if the air over water tank is not big enough, I guess I could see a diaphragm tank too. The pressure switch should be at the input to one of them, and the path between them should be not long and not narrow.

2. If two tanks, I would say the diaphragm tank would be second if you had two. Diaphragm is better than bladder. I would not want a WellMate pressure tank, because those have bladders rather than diaphragms. The air over water tank would get rid of the air. Are you looking at UT-80? That has a blowdown valve to let you blow out sediment.

I am not a pro.

 

[Sponsor]

 

[Valveman]

No, you do not need a bladder/diaphragm tank with a regular hydro tank. But many people add a diaphragm tank after the hydro tank. This is because hydro tanks are bad about becoming waterlogged, and having an extra diaphragm tank gives some protection from rapid cycling when the hydro becomes waterlogged.

However, if the hydro tank becomes waterlogged it is not draining back as it should, and the pipe will freeze. It is important to keep the control check valve, Schrader valve, bleeder orifice, and air volume control (AVC) working properly on a hydro tank system. If any of these devices fail the tank will waterlog and the lines will not drain back properly. If you maintain these devices and make sure the drain back system is working properly, a second diaphragm tank is not needed. But if like most people you have a hard time keeping these little devices working, adding a diaphragm tank might save the pump from rapid cycling. But again, in your case, the bleed back system is more important to prevent freezing than rapid cycling, so it must be maintained making the second tank unnecessary.

 

[LLigetfa]

I don't see any mention of tank size, pump GPM or water treatment system. The only reason to have a second tank is if the HP tank is not large enough to control contact time or to get at least a minute of pump runtime.

On my system I have two HP tanks in series to increase contact time and runtime. Having two AVCs also increases the removal of excess air. I don't have a bleeder/snifter/check valve drainback. I have air injection micronizer for iron treatment.

 

[Stan_N]

I don't see any mention of tank size, pump GPM or water treatment system. The only reason to have a second tank is if the HP tank is not large enough to control contact time or to get at least a minute of pump runtime.

On my system I have two HP tanks in series to increase contact time and runtime. Having two AVCs also increases the removal of excess air. I don't have a bleeder/snifter/check valve drainback. I have air injection micronizer for iron treatment.

Thanks for responding! The air over water tank is the Wellmate UT-40, and the bladder tanks is the Wellmate WM-12. These were not the installer's top choice, they were all that were available. For some background, the installer was installing a new water softener, and he broke my older air over water tank in the process. This sparked this as an emergency installation and these were the best tanks they could find that were available.

I believe the GPM on my water pump is 7 GPM. For water treatment, we have a sediment filter and a north star water softener.

 

[Stan_N]

1. Normal is to not have the second tank. But if the air over water tank is not big enough, I guess I could see a diaphragm tank too. The pressure switch should be at the input to one of them, and the path between them should be not long and not narrow.

2. If two tanks, I would say the diaphragm tank would be second if you had two. Diaphragm is better than bladder. I would not want a WellMate pressure tank, because those have bladders rather than diaphragms. The air over water tank would get rid of the air. Are you looking at UT-80? That has a blowdown valve to let you blow out sediment.

I am not a pro.

They used a Wellmate UT-40 for the air over water tank and a Wellmate WM-12 for the bladder tank. In his defense, this was an emergency install and most parts are not available, so I don't think this was his top choice. Should I try to change them out?

He installed in the order you recommended (well --> air over water tank --> bladder tank) so hopefully we're good there.

 

[Reach4]

Wellmate WM-12 bladder is in theory replicable. I think that seldom happens in practice. Sometimes people have tried the next size up bladder to try to get longer life. It is an interesting design. The bladder contains the air, and the water is in the tank outside of the bladder. I think that bladder is replaced from the top.

I suggest that you check your air precharge annually, or maybe even semiannually. Air precharge is always checked and set with the water pressure zero. I think the bladder would have more area for air to diffuse thru vs a diaphram.

That ET-40 is a 40 gallon tank. That could be sufficient. You could just leave provision for a precharged tank, and add it later if that proves desirable.

Yes, a lot of precharged pressure tanks were in short supply.

One quirk of the air over water system: if the power goes out, or you turn off the power, as you exhaust the water in the tank, it will send a blast of air thru your plumbing. That could startle you at the kitchen sink.