Shut off valve before or after pressure tank?

[bco2jco]

Hello,
I am installing a new diaphragm pressure tank. I purchased a pipe "T" kit as a package. It includes pipe T, connecting fittings, pressure switch, pressure gauge, drain valve, relief valve, and a shut off valve.

I will be installing it myself and I am pretty familiar with the system and confident i can do it correctly. My question is where should the shut off valve be placed? Should the shut off valve be before the tank (between the pump and the tank) or after the tank (between the tank and house supply)? Are there compelling reasons for one location vs the other? I am thinking it should be after the tank.
Thanks for your help.

 

[Reach4]

After the pressure tank!

The compelling reason is what would happen if somebody closed the valve while the breaker is on.

To shut off the water before the pressure tank, just open the breaker (or switch if you have one).

 

[Sponsor]

 

[bco2jco]

Yeah, that makes sense.
The somebody to close the valve and forget to reopen it would be me!
Thanks.

 

[Reach4]

Or a curious child.

 

[Valveman]

It is also good to have a shut off valve after the pressure tank and a hose bib on the tank. This is good for trouble shooting when there is a problem. While you are figuring all of this out you should study why a Cycle Stop Valve should be on the inlet of that tank tee you are installing.

 

[Reach4]

Hose bib on the tank is also important for flushing sediment. Flushing sediment I think should be initially annual unless you have a lot of sediment or almost no sediment.

Similarly, checking the air precharge annually is a good initial schedule, although you may find that can go longer if your tank has an all-butyl diaphragm.

 

[Sarg]

 

[LLigetfa]

IMHO it is a mistake to reduce the pipe size on the outlet side of the Tee. Also, right angles should be avoided where possible. Long sweeping bends are better. Don't get hung up on it looking pretty.

Low pressure cut-off switches are a nuisance and offer a false sense of security rather than protection.

 

[Reach4]

IMHO it is a mistake to reduce the pipe size on the outlet side of the Tee. Also, right angles should be avoided where possible. Long sweeping bends are better. Don't get hung up on it looking pretty.

I disagree on that first sentence. A 1-1/4 tank tee with one inch out, or even 3/4 piping (if a small house) out, is perfectly normal. A 1-1/4 tank tee typically has 1 inch FIP threads, in addition to 1-1/4 MIP threads. The tank tee offers very low resistance between the pressure tank and the pressure switch. Generally, if your precharged pressure tank is 34 gallon or larger, and if you use a tank tee, then that tank tee would be a 1-1/4 inch tank tee.

Up to 32 gallons, if you use a tank tee, it would be a 1 inch tank tee. That would have 3/4 FIP threads plus 1 inch MIP threads.

Right angle elbows in pressure piping are perfectly normal. I agree that a straight pex adapter with a pex bend would have a little less pressure drop, but I think the loss is fairly small. If the water will go to a backwashing iron filter, then you want to minimize pressure losses.

I do agree that if using PEX in a typical house, it would be better to use 1 inch PEX up until the water to the water heater splits off. 3/4 pex with crimp/clamp fittings is probably to be avoided out of the tank tee.

 

[LLigetfa]

I disagree on that first sentence. A 1-1/4 tank tee with one inch out, or even 3/4 piping (if a small house) out, is perfectly normal. A 1-1/4 tank tee typically has 1 inch FIP threads, in addition to 1-1/4 MIP threads.

I am not talking about the 1 - 1/4" out. The OP has a reducing bushing on the 1" out into which there is a 90 degree elbow into what looks like a PEX B nipple. If using PEX A or B but especially B, I would run 1" to the manifold and I would not use elbows. Why introduce flow restrictions just to have a tidy "look"?

 

[Reach4]

I think that is a MIP to F1807 (brass crimp/clamp) elbow. But I also agree that upping that diameter would be worthwhile if it was not already in service.

Your system needs you to minimize pressure losses more than most. Most users are not on as strict of a PSI budget.

I think you still use the venturi-type micronizer, right?