View Full Version : Goodbye PB hello PEX + manabloc

08-20-2012, 09:14 PM
I have a 1989 poloron mobile home that has Qest PB. Fitting have been failing, and it's time for a re pipe. So, I have installed a 14 port manabloc and am running PEX lines to each fixture. I know many of you do not really like the manifold home run set up and say branch and tee is cheaper in the long run. My reason for doing the manifold is primarily to remove any connections that will not be exposed (mostly in the underbelly).

My main question is regarding water pressure, as it is not the best with the current PB set up, and I am hoping it will be better with the new design. In the existing design there are seven PB elbow fittings in the main 3/4 supply line before it hits the tee and supplies the water heater and main trunk. Then there are some more elbows going to the water heater and a weird short bottle neck of half inch copper (who knows why, it was a repair done while the previous owner lived here...) Also, the main 3/4 cold trunk only runs a few feet and then most of the tees are off half inch PB line...

My new design only uses one 90 to bring the 3/4 supply up into the water closet, straight into the water meter, then tees off to the water heater and runs up in a sweeping bend to supply the manabloc. The total length of the 3/4 supply from the elbow up to the manabloc is around 8 feet. The hot supply for the manabloc will also be supplied with a sweeping connection to the manabloc free of any connectors or elbows. From there, it's half inch lines out to each fixture.

Do you think I will see a nice increase in water pressure/flow in the shower, garden hose, etc... By removing the restricting elbows from the current supply line setup?

08-21-2012, 04:58 AM
you probably won't notice much a of a change i would think.. PB also has a larger inside diam than PEX.....so you're losing there....but its stil a good swap...PB is JUNK for sure

08-21-2012, 07:56 PM
Oh well, I was hoping for a bit of pressure increase in th shower. It's no horrible, but would lie it to be a bit stronger. Coud I run two hot 1/2 in and two cod 1/2 in lines to th shower and tee them to increase it? If so, would check valves be required to prevent the teed lines from back flowing into one another?