Monday, December 16, 2013

Plumbing with PEX and Tankless Water Heaters

Pex, pex pex, how do I love thee, let me count the ways.
1. Never a gonna light anything on fire plumbing with PEX.
2. No meth enthusiasts are going to rip it out of the walls to sell for drug money.
3. So, so much faster...especially with the cordless expander tool.

But seriously, PEX is freaking awesome, especially the Uponor brand.

Here's my super awesome and easy to read plan.
Can you see why my physic students hated my writing?

Tankless Water Heaters
We decided to go with the Navien brand. This is a Korea made unit with
some interested differences from the Rinnai and Aquastar brands we have
used in the past. These units have stainless steel heat exchangers (instead of
copper on the other brands) and a built
in buffer tank and circulation pump. That means, no cold water sandwiches'
and you can turn the flow all the way down to barely a drizzle. Try that with
a Rinnai unit.
The first gen of these units had problems but I've been convinced that these
second gen models have fixed all the issues. Lets hope.....
The unit on the left is for the basement apartment and the unit on the right
is for the main floor of the house plus the laundry room.
Yep, we are separating the water heaters. There will no longer be a single
crappy Home Despot water heater in the attic supplying hot water to the
entire house. BTW, at one point that was three kitchens and seven baths!

The tankless heaters are condensing units that required 3" venting.
It was a tight fit but we managed to get them all in one joist bay.

One of the pex manifolds.
For some reason I forgot to photo graph the other manifolds.
Remember that these are in-progress shots so no, the PEX tubing isn't
completely supported yet.

Those four 1/2" runs on that manifold run to the kitchen and guest bath
of the apartment.

Bath Tie In
I decided to not completely re-invent the wheel on this retro-fit plumbing.
Originally the two 1/2" copper lines fed the guest bath and the kitchen.
Now the kitchen has its own line.

Hopefully this means that someone can be taking a shower and someone
can be using the kitchen sink at the same time.

Above you can see the start of the utility chase.
Here's a better shot.
Water, gas, electricity all through out the house and nary a joist will have to
be drilled....I hope.
Yes, its starting to get ugly in the chase and the wires are all temp supported.
When we are done running all the utilities we will build out a wood frame for
the chase and attach everything for real.

The Tool That Makes This All Possible.
Man, if you've ever done a lot of hand expanding on 1" PEX you will view
this tool as a godsend. Annnnnd the great thing about this tool is, used models
sell for barely less than new ones.
Trust me, if you are going to do a lot of Uponor PEX you need one of these things.

The Dark Side of Uponor PEX
Like every pro will tell you. Don't use product lines that are not supported locally...
I ignored this advice and wow, now I've paid the price, twice...
Since the only way for me to get Uponors Products is from PexSupply,com I have
to order EVERYTHING online and wait......
As a first time Pex'er what are the chances that I'm going to figure out every
single PEX widget that I'm going to need?
Slim and None....
My PEX-ification of the house has had to stop twice now while I waited for

Up Next:
Yep you guessed it, more catch-up posts.


Anonymous said...

Are the Alameda inspectors fine with PEX?
I was considering PEX for a small bathroom remodel but stayed with copper since a guy at Paganos told me that it's not up to code in Alameda if hidden behind walls.

The MadScientist said...

It used to not be legal in CA at all .
PEX has been allowed officially in the CPC for at least 3 yrs now.
The city will probably make you prove your cert in whichever system you use though.

Farrell Mackennon said...

We are steadily using PEX products a lot more in our plumbing company and, on the whole, find it of a high quality and easy to work with, and good value for money. It’s used in all kinds of products, including underfloor heating and other domestic plumbing needs.

Anonymous said...

Hey MS! What resources did you use (or would recommend) to familiarize yourself with the ins-and-outs of design and installation of pex plumbing? Your post has me excited for the possibility of really customizing like you have. It'd be great to get rid of the icky galvanized this year.

Thanks! And you guys really rocked it at Halloween! Keep on keeping' on!


rosely said...

Hi I have a small 600 sq foot cottage that will be used in fair weather in MI. Was wondering if you had an opinion on what kind of tankless to use with pex plumbing?

rosely said...

any thoughts on what tankless to purchase for 600 sq ft cottage to be used only 6 months of the year in MI? We are plumbing with pex. thanks

The MadScientist said...

Hi Rosely,
I'm sorry this took so long to get back to you.
Okay with these assumptions. Its a warm weather only small demand situation in a tiny place. You are on propane I bet too?
I would recommend the smallest Rinnai heater that can be mounted on the exterior (so you don't take up any inside space). When you leave for the season you drain the water right?
I'd cover the TWH with a similar cover to what people use to cover their AC condensers during the winter.