Author Topic: pipe size  (Read 1184 times)

MChesmore

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pipe size
« on: November 27, 2016, 09:01:20 PM »
Hello,
I have a question on Line Size.

I just installed a new pside kick system on my plumbing system and found out that I had a bad check valve on my submersible pump. I replaced the pump with a new 3/4hp pump (8.8gpm) hung on 1" line to pitless adapter. from there it reduces to 3/4: copper and runs about 14' to inside the house. This is where I installed the pside kick kit. I reduced fittings to 3/4" and ran the 3/4" output to a PEX manifold. From there it reduces again to 1/2" circuits. ALL of this is brand new. I just installed a new bathroom (all fixtures are new) and I'm not getting very much volume out of the vanity faucet or shower/tub (Delta fixtures). I am getting 50lbs of pressure @ 3gpm. In fact I can get 55lbs @ almost 5gpm, but when just running say the vanity faucet something like 1gpm it running almost 60lbs just below cutoff, but it doesn't seem like I'm getting that much pressure or volume. A garden hose hooked directly up to the low point drain will lift itself up under pressure, so I know i'm getting good output pressure 18" from the CVS valve but beyond that I'm flustered.
So do you think my line size is actually reducing my volume that much?

Cary Austin

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Re: pipe size
« Reply #1 on: November 28, 2016, 08:03:56 AM »
The CSV is giving you good pressure at the tank location.  You are losing pressure between the tank and the low pressure fixtures.  Do you have a filter with a dirty cartridge?  Do you have a bad ball valve or maybe just partly closed?  It could also be the aerator in the sink and the shower head that are restricting the flow.  If none of these things are causing the problem then you probably just have too long and too small of pipe to deliver the volume needed.

You could up the pressure to 50/70 and set the CSV at 60.  This would help with the pressure loss after the tank.

MChesmore

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Re: pipe size
« Reply #2 on: November 28, 2016, 08:57:14 AM »
No filters between tank and manifold, only the Water Softener, Ball valves are fully open and I removed the low flow limiter from the shower head. That being said, the distance from the tank to the manifold is approx 8' and distance from from manifold to shower fixture is approx. 20'. So 8' of 3/4 and 20' of 1/2 PEX, that doesn't seem like too much pipe, but I agree I do have pressure at the tank, but before the softener. All of this plumbing is brand new, even the softener. Do you think the WS could be reducing the pressure/volume? I say volume because I think its a volume problem more than a pressure problem.

Cary Austin

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Re: pipe size
« Reply #3 on: November 28, 2016, 10:31:33 AM »
Sounds like a problem with the softener.  Does it have a bypass valve?  If so try it and see if the pressure is better.

MChesmore

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Re: pipe size
« Reply #4 on: November 28, 2016, 07:03:51 PM »
no diff. after by-passing water softener. Raised pressure to 50/70 and there is somewhat of a difference. I have identified another problem that it very well could be, although it should not affect the cold side of things. The problem is that the supply lines to and from the water heater are only 1/2" copper. SO to recap my current plumbing line setup. 3/4 from pump to CVS to Manifold. I tapped into a 3/4" copper cold line coming from the manifold (back feeding) to temporarily keep house running, but it reduces to 1/2 going to the water heater, about 12' then it returns 1/2" hot, around 40' before up sizing back to 3/4 to feed the manifold.
I can see a very noticeable pressure difference in the shower when messing with the hot side of the vanity faucet. So I think maybe my pressure loss is allot more on the hot side. I won't be able to find out for sure until the hot water heaters are relocated and I can up size the supply's to 3/4.

Cary Austin

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Re: pipe size
« Reply #5 on: November 29, 2016, 07:00:04 AM »
I think up-sizing the line will solve the problem.  You have a restriction in the line somewhere and that 1/2" pipe is probably the culprit.  You can only squirts so much through a 1/2" pipe no matter how much pressure you have.  Then the hot water side will have even more restriction because it also goes through the water heater.

KULTULZ

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Re: pipe size
« Reply #6 on: February 09, 2017, 10:33:58 AM »
Just a reminder, PEX has a smaller inside dia. of say comparable sized copper or CPVC. And adding to this is the size reduction of the PEX fittings, depending on the PEX system you decide to use..

Rule of thumb is if using PEX, is to plumb 1" where 3/4" copper/CPVC is normally used and 3/4" PEX where 1/2" copper/CPVC has previously been used.

I hope this helps.

Cary Austin

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Re: pipe size
« Reply #7 on: February 09, 2017, 04:03:22 PM »
Just a reminder, PEX has a smaller inside dia. of say comparable sized copper or CPVC. And adding to this is the size reduction of the PEX fittings, depending on the PEX system you decide to use..

Rule of thumb is if using PEX, is to plumb 1" where 3/4" copper/CPVC is normally used and 3/4" PEX where 1/2" copper/CPVC has previously been used.

I hope this helps.

Good catch!  Yeah those insert fittings in 1/2" pipe are probably only about the size of 1/4" pipe.

Thanks