Water Heater Help - No Pressure

[buckle97]

Anybody out there use the Sharktoorh Pex fittings??? It's my understanding that size wise they maintain the same ID as copper.. They are pricey, but they will work on copper tube too... Simple push on fit without a torch...

I have also invested in a PEX crimp tool so that is what I use. I have used SharkBite in the past, but my impression (based mainly on cost) is that they are useful for repairs but not practical for new installs.

 

[sawdust_maker]

I've replaced the plumbing in two houses with Pex. And I've learned a couple of things, although I don't profess to be an expert. 1/2" pex is not the same as 1/2 copper or cpvc. Because of the way they connect, the restriction comes from the fittings. They go inside the pipe, and then you have the thickness of the metal in the fitting. So it does really restrict flow. I didn't notice it as much with the first house I did because I replaced old galvanized that had restricted flow from rust, etc. But then I redid a house that had copper, and noticed it big time. (The copper pipes had to be redone, I don't just pull it out for the **** of it) Think about it, with cpvc and copper, your 1/2 pipe goes inside the fitting. And 1/2 copper has a thinner wall also. So pex, while great, does reduce flow. For me, next time it will all be 3/4 pex.

A few years ago, I ran an outside line for a hose under our deck to a new spot. I wanted a hose bib down at the bottom of our stairs so I could use it to water the lawn down there when necessary. It seemed like 1/2 inch pex was perfect for this, given that I would normally have plumbed it in 1/2 inch copper, this should be no problem. We have plenty of water pressure, and the hose bib was going to end up roughly 10 feet lower than our basement. So no pressure problems, or at least I thought not.

Surprisingly, the water pressure at the end of about 40 feet of pex line, with NO kinks in it, was terrible. And there were definitely no kinks in the line, only a connection at one end to copper, and the bib valve at the end.

No more pex for me.

John

 

[captaincrab55]

I've used them as repairs were I didn't want to solder but prefer the crimps a lot cheaper if you own a crimper like I do.

If you only have 3 or 4 fittings I'd forgo the cost of the crimper ad use shark bites.

tom

Just for the record, I have a crimp tool too... I use it for Hot Water Heat fixes...

 

[SPYDERLK]

There are ADVANTAGES to smaller lines in some cases - I am considering running 1/2 copper "trunks" to my upstairs bath in the new house so that hot water will get there quicker. The area (and thus volume) of 3/4 pipe is 2-1/4 times that of 1/2! I have plenty of available pressure, and the upper bath will probably not be used a lot.

- Jay

Sure, bigger is almost always better.

I agree with JRobyn. With copper, I have always used 3/4" cold water mains, with 1/2" to individual fixtures. 3/4" to the hot water tank, but all hot water goes in 1/2" just because the hot water gets to the fixture much faster.

Im with both of you. I was getting ready to say the same. 1/2" will flow plenty of hot water... and waste less.
larry

 

[bp fick]

I am gonna try this one last time.

One trunks, main lines, with 3/4" or larger so that one can feed multiple 1/2" riser lines to individual taps, showers, faucets etc. The purpose of trunking with 3/4" is precisely so that if 2 faucets, toilets, showers, whatever are open at once, there is no appreciable loss of pressure, because 3/4" can supply two or three lines drawing at 1/2" each.

Flow dynamics 101. Fluid power. Similar principle in steam piping, dry land irrigation systems, etc. Main Tree trunk down to smaller branches, down to little stems. This principle is even found in nature.

If you start out with 1/2" and expect to supply a half dozen tap points, that is far too many "divides" of the water to not expect a major drop off.

Fixing something up in a rental house, as the OP states is one thing. He just wants to get by. I empathize. Laying out a quality plumbing system in a new build or re-model is something altogether different.

 

[dave1949]

I am gonna try this one last time.

One trunks, main lines, with 3/4" or larger so that one can feed multiple 1/2" riser lines to individual taps, showers, faucets etc. The purpose of trunking with 3/4" is precisely so that if 2 faucets, toilets, showers, whatever are open at once, there is no appreciable loss of pressure, because 3/4" can supply two or three lines drawing at 1/2" each.

Flow dynamics 101. Fluid power. Similar principle in steam piping, dry land irrigation systems, etc. Main Tree trunk down to smaller branches, down to little stems. This principle is even found in nature.

If you start out with 1/2" and expect to supply a half dozen tap points, that is far too many "divides" of the water to not expect a major drop off.

Fixing something up in a rental house, as the OP states is one thing. He just wants to get by. I empathize. Laying out a quality plumbing system in a new build or re-model is something altogether different.

Makes sense to me. A 3/8" toilet riser can't take enough water away to starve a shower on 1/2". And they are both being supplied by 3/4" trunk.

With a quality plumbing design, it should be very rare to have any appreciable loss of flow at any one point, regardless of what combination of uses are going on at the same time.
Dave.

 

[SPYDERLK]

I am gonna try this one last time.

One trunks, main lines, with 3/4" or larger so that one can feed multiple 1/2" riser lines to individual taps, showers, faucets etc. The purpose of trunking with 3/4" is precisely so that if 2 faucets, toilets, showers, whatever are open at once, there is no appreciable loss of pressure, because 3/4" can supply two or three lines drawing at 1/2" each.

Flow dynamics 101. Fluid power. Similar principle in steam piping, dry land irrigation systems, etc. Main Tree trunk down to smaller branches, down to little stems. This principle is even found in nature.

If you start out with 1/2" and expect to supply a half dozen tap points, that is far too many "divides" of the water to not expect a major drop off.

Fixing something up in a rental house, as the OP states is one thing. He just wants to get by. I empathize. Laying out a quality plumbing system in a new build or re-model is something altogether different.

Obviously. But the 1/2" has too many +s in a normal house for hot water unless people try to make it unsuitable by conscious actions of stupidity.
larry

 

[2manyrocks]

Conscious stupidity? Is that like the Three Stooges?

I used to live in a house where the galvanized water lines were so constricted by build up that a garden hose would have been an improvement.

 

[Highbeam]

Or with that cheap pex you could just make a bunch of home runs to a manifold fed by a large diameter line from the water heater.

I should say that my house was built in the 1960s which is why it is all half inch copper. I doubt codes would allow that these days.

Haven't you guys heard of pressure sensitive shower valves. You will no longer be scalded when someone flushes the toilet and reduces the cold water pressure. There is technology to prevent that now. In addition, with the low flow shower heads that we should all be using the flow needed to run that shower and sink are very low. You'll notice that it takes longer to refill the toilet though if they are all fed from the same 1/2" pex line as my bathroom is.

Sharkbites do insert a gizmo into the pex so they do reduce the flow vs. not having a fitting or a completely external fitting. I like sharkbites and use them because I don't own the crimping tool.

 

[buckle97]

I looked under the house to see water coming out of a hot water line under the kitchen. This is the last bit of remaining CPVC that I didn't replace with pex.

I replaced this last run with pex over the weekend and now all my pressure problems have been solved. I have equal pressure on the hot and cold sides.

Thanks everyone!