Kitchen sink low flow/pressure

Newish installation. The kitchen sink cold water is but a trickle, hot and mixed works as expected

Cpvc is roughly 50 feet. Hot is 1/2 inch and cold is 3/4. Pressure tank seems to be a few psi low, maybe 38 kickin.

I know up sized piping will reduce flow but I couldn't imagine this much.

Before I run new piping what or how could I test to ensure it's not a different problem? Or would it be expected that 50 feet of 3/4 supply be unable for sink plumbing?

TIA

walkeasy7 said:

Newish installation. The kitchen sink cold water is but a trickle, hot and mixed works as expected

Cpvc is roughly 50 feet. Hot is 1/2 inch and cold is 3/4. Pressure tank seems to be a few psi low, maybe 38 kickin.

I know up sized piping will reduce flow but I couldn't imagine this much.

Before I run new piping what or how could I test to ensure it's not a different problem? Or would it be expected that 50 feet of 3/4 supply be unable for sink plumbing?

TIA

Click to expand...

Can you explain why you think upsized pipe will REDUCE flow? I am not a plumber, but that seems illogical, and contrary to anything I have ever heard or read.

My guess is that you have debris blocking the line at the shutoff valve or possibly at the faucet.

jeffmatteters is right disconnect the line in question flush
it out into a bucket if no flow check flex supply

So far the advice is correct.

Start with flushing out the cold shut off valve. If its a brand new kitchen faucet, most of them come with the water supplies attached so you wont be able to use that.

You can purchase a 24" stainless steel water supply, connect that to the cold shut off, then turn the valve on and drain it into a bucket. If you have full flow there, that's good. Check the bucket for any kind of debris, pebbles, rocks, etc.


Now you can place the cold water supply coming from the kitchen faucet into the bucket, make sure the hot shut off valve is on and turn the kitchen faucet on, in the middle, between hot and cold, if its a single handle faucet. If its a two handle, turn the hot all the way on and turn the cold all the way on.

This will allow the hot water to flow through the kitchen faucet and back out through the cold water supply into the bucket. This is called back-flushing and will, hopefully, clear any debris in the cold side of the kitchen faucet.

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