Junk bypass water valves

My guess is that in all that winterizing, you wound up blowing/dumping just a bit of water into the tanks. The tanks being empty, of course, that water went to the lowest point, the drain valves, and there it froze, causing the valve or the pipe to crack. It wouldn't take but a cup or two of water to cause that, and there's surely that much in the sink/tub drains, let alone in the lines.

That's just a guess, of course.

Did you leave the ball valves open to remove the water between the ball valves and the hot water check valves. If you closed them then drained, there is still water behind the valve, Jerry

What 2 bypass valves?
Are you talking about the valves on water heater?

Are they attached to the PEX line using bands?

If banded......cut band into diagonally across band carefully. I know PITA to access. But if you cut almost all the way thru then you can twist them off.
Then go buy some Sharkbite shut-off valves......3 of them
Install one on cold inlet, one on hot outlet and one on line that connects cold/hot (bypass line)

Sharkbites just snap on, Don't leak and are very good quality. Home Depot.
Lowes carries similar called Gatorbite

The End of PEX needs to be clean straight cu and no burrs.

naturist wrote:
My guess is that in all that winterizing, you wound up blowing/dumping just a bit of water into the tanks. The tanks being empty, of course, that water went to the lowest point, the drain valves, and there it froze, causing the valve or the pipe to crack. It wouldn't take but a cup or two of water to cause that, and there's surely that much in the sink/tub drains, let alone in the lines.

That's just a guess, of course.

The OP said "by pass" valves. Not "drain valves"

Jack L

Those plastic 3-way bypass valves are pretty commonplace and not normally an issue. I would say it was either water trapped inside or potentially (although rare) compression clamps that were over-tightened at the factory which cracked the fittings. Perhaps it got cold enough for the anti-freeze to freeze? The winter was extra nasty this time. I assume the anti-freeze was undiluted.

You don't need to use 3-way valves. You could do it with 3 regular valves instead. If you need a little more PEX tubing after cutting out the old valves, regular household PEX is fine. I'd get a PEX tubing cutter - they don't cost much.

There are 6 different ways to connect PEX tubing. 6 ways to connect PEX I use copper crimp rings in our TT but only because I already have the crimper tool. For only a few connections, Sharkbite is the way to go plus they can easily be pulled apart if ever needed with the special tool.

You can also remove the compression clamps by using a pair of pliers (with flat nose) and wiggling the crimped piece that sticks out back and forth until it loosens up enough. You can use a small screwdriver if needed to pry it apart. Or just cut the tubing...

Sharkbite would definitely be the easiest but they're the most expensive and I'm not sure if available in a 3-way valve. Seatech makes a marine plastic version which is available at Dyersonline: Seatech 3-way valve Not bad at just $13 (before shipping) or $13.50 on ebay with free shipping. Likely available at local marine stores for 10 times the price, lol.

Thanks for the replys guys and gals, I was just a bit frustrated at having to replace plumbing after 1 year, ah well,all is good now.

Yes, RV plumbing is cheap, do doubt about it.
I've gone to flow-through brass and stainless ball valves, one on every supply line and the main supplies. The avoided headache of a valve replacement or a leak is worth the price.