Low pressure on hose bib

[marvingreenberg]

On one side of the house, the hose bib has great pressure. On the other, it's just a gentle flow. I took apart the external valve, and the internal shutoff and everything "looked" ok. I had some free time, so decided to replace the ancient (75 year old?) external valve and the internal shut off. And the pressure got slightly better.

The side that has good pressure is fed from 3/4 galvanized. This then goes to the other side of the house, about 25 feet and three or four turns. Then at the very end, it goes down to half inch pipe, with a few more turns.

Is this last little bit of half inch pipe enough to drastically reduced the pressure? Or is something else going on?

 

[CountryBumkin]

It sounds like there is a restriction in the piping. Probably scale build up from age. If you put a pressure meter on the hose bib with the low flow, I bet it will have the same pressure as the other bib - just not the flow.
Have you checked the pressure? Do you have one of these http://www.homedepot.com/p/Eastman-...gclid=CM7s7aDhttQCFQUEaQodt7MDyg&gclsrc=aw.ds

 

[Sponsor]

 

[Jadnashua]

Galvanized piping starts to degrade from the moment it is exposed to water. The ID of the pipe is probably reduced to something like a soda straw. It usually is worse on hot water supplies, but can easily happen in cold as well over time. You should start planning and saving to consider a repipe of the house. Until then, you live with what you have.

FWIW, when new, a 3/4" pipe's interior volume is 2x that of a 1/2" pipe, so should flow lots more water with fewer restrictions than a 1/2" pipe. Galvanized pipe after it starts to rust on the inside can become both quite rough (increased friction will drop the working pressure, not the static pressure), but also because rust is bigger than iron, narrow the passageway as it progresses. Eventually, if things get bad enough, it will rust through. Then, you won't have a choice about replacing things. I see pex or copper pipes in your future.

 

[MACPLUMB]

Start with Black Iron street 90 and the black iron nipples all the way over to the Galvanized union what
Jadnashua posted holds double for Black Iron, which is for Gas or Steam piping "NEVER" for water

 

[marvingreenberg]

So, maybe just replacing the last bit of 1/2" pipe with copper will help, since it may be the worst restriction. The 3/4 run is supplying the hot water heater too, and there seems reasonable hot water flow in the whole house.

Thanks for the explanations.