T-ing Two Water Supply Lines for Greater Water Pressure

[JZeld]

I am about to install a prefabricated steam shower (this one here -- http://www.amazon.com/dp/B003XZ60VW/?tag=skimlinks_replacement-20). If all goes well (famous last words) the steam shower should drop fit into the existing shower space. The existing shower has a shower head on each side so I have water supply on btoh sides. I was thinking that it might be beneficial to connect both sets of supply to the new shower to increase the water pressure a bit. Do you guys see a problem or any advantage to doing that? Otherwise, I'd just cap one supply side and keep the other.

Thanks in advance!

 

[johnjh2o]

If all it has is one shower head and one body spray you will be OK with one set of water lines. Cap the others. If you have access to the lines cap them below the floor, the less pipe you have in service the better off you are.

John

 

[JZeld]

Thanks John. It has many body jets, which is why I was thinking that having both lines hooked up might be beneficial. Is there any downside to hooking up both lines?

 

[Chris]

Hooking them both up will not give you any more pressure then what you have now but it may increase volume a bit. Also the larger the pipe size the greater the volume and I believe that is what you are looking for anyway.

 

[LiQuId]

Ask yourself.

do i want a shower with 80psi and 1 GPm

or 80 GPM ( gallon per minute ) and 1 psi ?

Pressure is used inly to get the water to where it needs to be, there is no real advantage in T ing the lines.

 

[JZeld]

The lines are already there. I understand what you are saying about pressure versus volume, but I'm thinking now that I might need additional volume too because of all the jets. Any disadvantage to T-ing them?

 

[speedbump]

Do you know where the second line comes from? Do both lines come seperately from a larger pipe somewhere near the supply or does one of these lines simply tee off the other? If it's the latter, they are both actually the same line.

If your old shower had two heads that used maybe 2.5 gpm each and this new one has more heads, your original plumbing probably isn't sized to handle the additional usage. You might have to run around in there just to get wet.

 

[LiQuId]

what was the other line used for originally ?

I couldnt really say there is a disadvantage in ting them other than the work involved which may be to no gain.

 

[JZeld]

The other line was for another shower head in the same shower, opposite ends of the 59" shower stall. I need to figure out if they are running off the same line. I don't remember water flow dropping when I turned on both shower heads though.

 

[LiQuId]

seems likely then that it is a separate line, If you can try filling a bucket with one line ( 10 gallon idealy ) and only one line flowing. then repeat this filling 2 buckets one from each line, if they are on the same line then the buckets should fill slower one the second attempt ( obviouslly only measuring one bucket the other is to catch the water and keep the line/lines flowing ) if they are on separate lines then they should fill the same each time... roughly.

I should mention that this is not something i've done, but I can see no reason why it wouldnt work. obviously It would be easier if you were able to physically see the 2 lines.

another thing that may work,

Turn the house water off, and then blow down one of the lines... if they are connected nearby then you should get water rising out of the opposing line.. again theoretically.

 

[chaseme5]

You mean installing 2 water lines in parallel to increase water flow.

You need to find out the flow rate (gallons per minute) the shower requires.
The manufacture should supply that information.

But yes 2 water lines in parallel will eliminate pressure drop if that is what you want to achieve. However if the shower requires 10 gpm for example, but the flow rate to your house is only 8 gpm, you are going to need more flow to eliminate pressure drop.

 

[LiQuId]

2 lines in paralel will not chang pressure drop since the pressure is constant and comes from one source. You seem to be confused as to the differances between flow and pressure.

 

[chaseme5]

To increase pressure the flow rate drops. However if you do not have enough flow you can not increase pressure.. Yes you are right the source needs to be looked at.

 

[LiQuId]

you seem to be thinking about pumps, but i assure you when you run lines in paralel you get increased volume yes, But you do not increase pressure the pressure in a domestic system is usually set by a Prv at the source and remains faily constant, this is where you CAN change the pressure in the Domestic lines if it were required. the flow rate however would remain the same through a given line in the system ( you cant get more out of a 1/2 " line than a 1/2 " line will supply. ) the only way to increase the flow rate would be to add another line ( and properly size the system I will add ) the only way that line IS going to supply more flow is if it remains its own line till It gets to the Point of use.

There is a relationship between flow and pressure but its not what your hitting on. remember what creates pressure in a Domestic System??

Head pressure,
and A pump.

 

[LiQuId]

http://mitchellscience.com/bernoulli_principle_animation

I think youre thinking of Berrnoullis principle, so in theory You can change the pressure in a system with the piping but this is really only used in a monoflow heating system which is seldom if ever used anymore... to my knowledge. And the pressure increases from a 3/4 to a 1/2" or such fairly minimal.

 

[JZeld]

Thanks to everyone for their input. I took down another wall for the shower only to find out that the lines already T-ed off of each other. I'm going to do as suggested and cap one of the lines and just use the other.

Thanks again.