Tankless Water Heater Valve Kit/Plumbing Help (Texas)

[FrozeninTexas]

Another one of the millions affected by the freeze down here in Texas. Have not been able to get a plumber out and cannot get moved back into our house until we get this issue repaired.

We drained all the water lines before the freeze so we were fortunate to avoid any broken pipes. However, we have a Takagi T-K4-IN tankless water heater and found that one of the valve drain caps apparently had some freeze damage and the valve was leaking very slightly out of the break in the drain cap when we turned the water back on (one drop at a time - see photo below). Out of an abundance of caution, went ahead and ordered a full set of identical valves rather than just replacing the drain cap in case there is any damage inside the valves themselves. I have experience with pvc plumbing/connections, pool plumbing and other plumbing basics but have not worked with these cpvc screw in type fittings before, making connections between copper and cpvc, etc. Can someone school me in what I need to be doing to get these new valves in? Is it simply cut off the old cpvc at a reasonable spot, unscrew the valves, clean the threads, apply new pipe dope/teflon tape, screw in new valves and then replumb the cpvc as before with a coupling added at the cut location? Is there a better way that I should be fixing this to avoid future problems like integrating pex plus (the rest of our house is pex plus) or using pre-fab hoses to make this easier?

My expected materials list includes - cpvc, 90's, pipe dope, teflon tape, adapters, couplings and the new valves (same as existing), cpvc primer and glue. What am I missing?

Is there anything to watch out for or anything complicated about this type of repair under the circumstances? Water is still off, house water lines are drained, gas cutoff valve to the tankless is off and don't plan to do anything with the gas line anyway.

Many thanks for any contributions you all may have. We appreciate it!

 

[Twowaxhack]

Replace all that with pex. Get rid of the cpvc and those flex copper things.

Or just leave it all alone if it’s working. You could get another cap for $3.00 at any hardware store.,

Leave the cpvc relief piping. Or you could change it and use a Brass mip x cpvc adapter instead of that all plastic one. Or Not . It doesn’t matttter.

 

[FrozeninTexas]

So I could just tear all that out and use Pex plus with shark bite male adapters on each end for both valves and the relief? Seems that would be pretty easy, no?

 

[Twowaxhack]

So I could just tear all that out and use Pex plus with shark bite male adapters on each end for both valves and the relief? Seems that would be pretty easy, no?

Technically pex insert fittings are not full flow so they should not be use on relief piping. See if I care.......see if it makes any difference, it doesn’t.

Just leave the cpvc for the relief there. Don’t waste your money replacing it. It’s fine unless its broken.

Pipe the rest with pex. Make sure of what type pex you have before you cut it. Get fittings before you start.

Don’t over tighten the service unions on the new valves. They have rubber washers to make their seal. Snug it up then check it, you can always tighten it a little if it drips.

I tighten everything tight but don’t be grunting with a 14” wrench.