Pex Leak Advice

Shoyrtt

Shoyrtt

Alamitos to Avalon
SILVER Sponsor
Jul 16, 2020
1,891
Alamitos Bay, CA
Boat Info
1999 450 Express Bridge, 9’ Achilles dinghy w/15hp Suzuki EFI
Engines
Caterpillar 3126TA
After I upgraded my water pumps, I believe what was once a pinhole leak in the Pex connection to the hot water heater decided after 22 years that it was time to give up. There is some rust around the bottom of the heater that suggests the leak has been there for a long time. I did notice that with both the old pumps and the new pumps, they would cycle occasionally, but I thought it might have been a toilet or something minor. I'm glad I caught this in the slip and not out on the hook.
Leak.jpg

My thought with the repair is to leave the T-fitting in place and put a coupling maybe half way down the line. I would then use a new piece of Pex to go from the coupling to the heater with a new connection to the heater where the current leak is. This is my fist time working with Pex. Any advice on my plan or the fittings I should use? Thank you in advance!
 
I had a small leak around one of my Pex fittings. Looking at it closely showed there was some scoring in the plastic under the fitting, probably from years of flexing while under way. I cut about 3/4 of an inch off of the end of the pipe and put it back together with no problems.
 
I replaced the same section of pipe several times. I’m guessing that the heat from the hot water out port on the tank takes it’s toll on the polyethylene pipe over time near the heater. I finally decided to try 2 inches of brass fittings and a whale insulated connector on the tank side and no issues since then.
 
LTD.330 said:
I had a small leak around one of my Pex fittings. Looking at it closely showed there was some scoring in the plastic under the fitting, probably from years of flexing while under way. I cut about 3/4 of an inch off of the end of the pipe and put it back together with no problems.
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Did you use a push to connect fitting or a crimp fitting? I'm also wondering if this was repaired at some time in the past? This appears to be the output line on the heater which should be a red line. Notice the lines after the tee are both red. Is there any difference in strength in the red lines vs. blue? Sorry for all of the newbie questions.
 
There's no difference in strength between red and blue (or white, for that matter).

Are you sure the tubing is leaking? The most common reason for leakage like this is that the tubing was not inserted all the way into the fitting. It needs to be pushed further than most people think. Just mentioning this in the hopes that you can fix this for free.
 
Yes, but I did stick 2 brass fittings between it and the tank, figured it would give a bit more protection against the heat.

The original out line would have been red so it probably blew out in the past. When I did my final repair, West Marine didn’t have any red 15 mm Polyethylene in stock, so I used blue.
 
Oh... check out freshwatersystems.com for fittings/line. Good company with knowledgeable people available to talk to.
 
For what its worth... I recently changed all of the copper water pipes in my house to PEX. The plumbing inspector told me that the PEX cannot connect directly to the water heater!? Neither the cold water inlet or the hot water out pipe. I had to install 18" copper pipe on both connections to keep the PEX away from the heater. I didn't ask why..... Very curious since 18" later, the PEX contains THE HOT WATER!! Go figure.
 
John Del Grosso said:
For what its worth... I recently changed all of the copper water pipes in my house to PEX. The plumbing inspector told me that the PEX cannot connect directly to the water heater!? Neither the cold water inlet or the hot water out pipe. I had to install 18" copper pipe on both connections to keep the PEX away from the heater. I didn't ask why..... Very curious since 18" later, the PEX contains THE HOT WATER!! Go figure.
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Interesting. I can't say I've ever come across a boat that used a short section of copper before going to PEX (not that means NONE do that, of course). The PEX always goes right to it. Same thing at my house... same thing at our cabins in Maine (going on 25 years like that, now).
 
I just re-plumbed my water heater in the boat. It was a new unit the PO never finished installing. I found several connections had been affected by what appeared to be hard water. Don't over think the connections. They "just" work. I've always been a copper guy. I love sweating/soldering copper pipes. PEX style plumbing is almost winning me over. Not quite sure yet.
 
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Lazy Daze, maybe the copper pipe requirement is a local ordinance? I live in Rhode Island. Not saying the PEX should be kept completely away from the water heater in the boat..... But maybe a short brass fitting into the water heater first. Also, please note that there is an orange PEX pipe that is designed to prevent air intrusion into the line which would cause rust in a heating system.
 
John Del Grosso said:
For what its worth... I recently changed all of the copper water pipes in my house to PEX. The plumbing inspector told me that the PEX cannot connect directly to the water heater!? Neither the cold water inlet or the hot water out pipe. I had to install 18" copper pipe on both connections to keep the PEX away from the heater. I didn't ask why..... Very curious since 18" later, the PEX contains THE HOT WATER!! Go figure.
Click to expand...

A lot of states plumbing codes don't allow pex to go directly on to the hot water tank. Has to do with the heat and expansion / contraction of pipe and fittings, different rates which leads to leaks down the road.
 
I finished up the repair today so I thought I should follow up with a postscript. Whale Pumps makes a braided line specifically for water heaters . Because the Pex fitting failed, I figured the braided line should be more stout. It then ends at another Whale brass fitting with a short piece of Pex before the tee fitting. I did a little cleaning and paint and it’s looking good.
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seaRayHeater.jpg
 
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Shoyrtt said:
I finished up the repair today so I thought I should follow up with a postscript. Whale Pumps makes a braided line specifically for water heaters . Because the Pex fitting failed, I figured the braided line should be more stout. It then ends at another Whale brass fitting with a short piece of Pex before the tee fitting. I did a little cleaning and paint and it’s looking good.
View attachment 101750
View attachment 101749
View attachment 101751
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One of the issues I had was my outgoing (red) pex was in a bind from the wood of the couch frame. I cut some out to allow it to enter straight, (or at least more straight). This braided hose would be better for that also, looks great!
 
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