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 Shower Valve Pfister Low Water Pressure
Author: HeathenHero (AZ)

Hi everyone,

New to the site and to plumbing. I am a superintendent building apartments right now. We have an issue with both water pressure and hot water at our tubs only. The shower valve being used is a PFISTER OX8- 340A. I have checked to make sure they are installed correctly, changed cartridges, cleaned the screens etc. When we increase water pressure at the valve it sends water out of the shower head without activating the diverter. Once we decrease pressure at the valve it takes away hot water and the pressure becomes unacceptable. How can we increase pressure but keep it from running out of the shower head and retain hot water? This is happening in every single unit. The plumber seems to have run out of ideas and I am at a loss of ideas. Any help would be appreciated. Thanks in advance.

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 Re: Shower Valve Pfister Low Water Pressure
Author: Tom130 (IL)

What kind of pipe is between the valve and the tub spout?

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 Re: Shower Valve Pfister Low Water Pressure
Author: HeathenHero (AZ)

It is a 1/2in PEX line

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 Re: Shower Valve Pfister Low Water Pressure
Author: bernabeu (SC)

THAT is the issue.

IMPROPER installation, said 'smallbore' piping is acting as a restrictor / divertor.

1/2 pex is equivalent to 3/8+ pipe and should NOT, repeat NOT, have been used for the spout.

see page 5: [pfisterstorage.blob.core.windows.net]


"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Edited 2 times.

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 Re: Shower Valve Pfister Low Water Pressure clap
Author: HeathenHero (AZ)

Thank you

Edited 3 times.

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