Pex, Bathrub and Water Pressure

Let me start off by saying that this forum has provided me with some very great advice thus far and i appreciate having a place to find information from pros and other DIY's.

So here is my dilemna.
I recently purchased a 3 bed 1 ba house and knew going into it that the bathroom tub had a leak in the p-trap and in the faucet. Turns out the problem was very extensive and i ended up tearing the entire wall out behind the tub as well as replacing the other 2 alcove walls with new backerboard and tile.
While i had it all taken apart i thought i should probably upgrade the 40 yr old galvanized as it leaked in a few other parts of the house. I'm not one to leave well enough alone so i researched and ended up installing a PEX home run system throughout the house. The main line underneath the house was converted to 3/4" pex to a manifold where i have 2 hose bibs, the full bathroom hookup, dishwasher, sink, and washer. These fixtures are all 1/2" pex lines so far (i haven't run the washer lines yet)

I had good water pressure before the install and i still do at every fixture except the shower valve. I can't get enough water output out of it. The lines are not very long as my manifold is about 10' away horizontally and the lines ran through the insulated attic and back down again so i don't think the length is the issue. The valves on the manifold are fine. The shower valve is a pfister 808m0bk.

I need to solve this quickly and any and all help and input is very appreciated.

Thanks again!

-Devin

upgrade from 1/2" pex to 3/4" pex for that shower line. It doesn't matter if a piece of it remains at 1/2", just make the longest part 3/4" in diameter, as much as possible.

That is what I might do, but I'm not there, and there are still many things I don't know about your situation.

You have said your 1/2" pex line to the shower is about 10 feet long.


How bad is the shower flow?

david

Tile is done at this point it would be a real pain to upgrade. I don't think that the 1/2" line is the issue though. The pressure to other fixtures that follow the same runs and go further than the shower are better than the shower. This leads me to think there is something on the valve that i missed when installing. i adjusted the temp range cap, but was there something else i'm missing??

more info:
Manabloc Manifold
3/4" supply to base inlet.
3/4" cold inlet/outlet services the water heater and then 3/4" line returns to the hot inlet/outlet for the manifold to service shower and sinks.

I will try to shut off all the valves on the manifold except for the shower and see if that helps tonight, any other thoughts or opinions?

Well in reading more on this site i have found that pfister is not necesarily a universally recommended brand here on this site. I just called their customer support and explained my problem. The woman was very nice and suggested a few things that i have already made sure to check. She then said she was going to send a new cartridge assembly at no charge to ensure that this was the problem.
Thus far i must say that is quite impressive to quickly try to solve an issue for the customer. after spending $144 on this fixture at lowes i must say i'm glad to see that kind of support as i don't always see it with other things i purchase.

If you guys have ideas on what else i can try please chime in, as this is mostly an insurance policy that the cartridge assembly works correctly and is not the issue.

Did you do the pex install yourself? I'm about to tackle ours and have the 18 port manabloc as well. If you did it yourself, how did you do your stubouts for the shower? This is the one area I'm still debating on how to do. I would like to keep it all pex and have seen some installs using the powerbars and metal bend supports to strengthen the stubouts.

i used drop ear supports for the shower and hose bibs. Attach them to solid 2x4 bracing and make sure you aren't pulling them tight and you should be ok.

I had already bought the drop ear metal bends so I think I'm good to go. I had planned on putting a 2x6 cross brace in and drilling a hole for the bend to slide in, seemed sturdier than some other pics I've seen like the one below.

Living4real,
How are you planning on venting that sink?

That's not mine Terry, I just found the pic online by google images "Pex Stub". I was just searching for pics of an all pex stub out without any copper, so I could pre-plan parts needed, etc.

That's funny you point out it doesn't look vented, because they're slogan on the website is something like "Building better homes" lol. In their defense maybe they haven't gotten to the venting part yet?

http://laurenhomes.net/index_files/Page305.htm


Brian