Trying to replace this leaking heater with a tankless, please help.

[gnr5]

Just moved into this house, South Florida, two stories, the heater is leaking and I'm replacing it with a tankless. I'm not sure how to plumb it since now I realized I have more pipes coming and going from the existing tank than what I expected, and I don't see a pump. I'm suspecting there is some sort of recirculating but I don't see a pump anywhere.

I just realized that the cold/hot water lines are flipped, because if I shut off the valve then I lose hot water.

I have five pipes that go to/from the wall

• THREE behind the tank (top) - one pressure valve, one of cold water, one hot water
• TWO behind the tank (bottom) - another cold water, and one that wraps around the tank and connects to the drain valve in front of it.

So, this is the tankless heater I bought. How do I pipe this thing? My questions are:

1. For the cold water, there is a T right now, do I keep the T and basically plug what's going into my existing tank into the tankless?
2. Same question for the hot water, do I just do a one to one replacement and connect the output from the tankless to my existing hot water pipe?
3. What do I do with the pipe that wraps around the tank now? Not sure what it does? Should I just cap it and call it a day??

I also made this video that shows the whole thing.

 

[GReynolds929]

No offense but you should not be attempting this on your own....Hire a pro!

 

[Jeff Handy]

You are eager but not ready for this.

 

[gnr5]

Sigh....

 

[Jeff Handy]

Better to sigh than to die.

 

[sarg]

I do not have any answers because the tankless units are a mystery to me ........ I do have comments and questions ..
The unit you purchased requires space for four 40 amp double breakers ... You have that much space in your service for the three additional double breakers ? ....... ( 160 amps to heat your water - wow ) Your picture shows the wiring in ..... Did you have to reconfigure the service end ?
I doubt your hot & cold lines are switched ... You are just turning off the "system" pressure.
I also suggest you take the advice of the experienced members here ..... getting things wrong by "fudging" could have serious consequences. Especially if it is a recirculating type system ...

 

[Twowaxhack]

Turn the power off.

Drain old water heater

Cut the pipes at the old water heater.

Determine hot and cold pipes at this point and pipe it to the new unit.

Leave the lower pipe turned off and cap it. Shorten it and cap it, whatever. If it circulated before, it won’t be now.

Make sure you’re getting water flow through the new water heater before you turn the breaker on.

Good luck

 

[gnr5]

Turn the power off.

Drain old water heater

Cut the pipes at the old water heater.

Determine hot and cold pipes at this point and pipe it to the new unit.

Leave the lower pipe turned off and cap it. Shorten it and cap it, whatever. If it circulated before, it won’t be now.

Make sure you’re getting water flow through the new water heater before you turn the breaker on.

Good luck

Thank you, really good answer!

I do not have any answers because the tankless units are a mystery to me ........ I do have comments and questions ..
The unit you purchased requires space for four 40 amp double breakers ... You have that much space in your service for the three additional double breakers ? ....... ( 160 amps to heat your water - wow ) Your picture shows the wiring in ..... Did you have to reconfigure the service end ?
I doubt your hot & cold lines are switched ... You are just turning off the "system" pressure.
I also suggest you take the advice of the experienced members here ..... getting things wrong by "fudging" could have serious consequences. Especially if it is a recirculating type system ...

I did have space, 160 amps if I have all the showers on, this is a big 5 bed/4 full baths house. If you don't need to have all the services on, then it will run on 40 amps.


For anyone else attempting this via DIYer, is really not that hard if you know how to handle the electrical. This is an "almost done" picture, everything is now capped.

 

[sarg]

Commendable.

 

[matt.mena]

Very nice outcome gnr5!

 

[JG plumbing]

Not a nice outcome.

Do not cap lines that are still hooked up to your plumbing system.

LEGIONELLA

Those capped lines are still hooked up somewhere. They will grow, and slowly distribute, disease causing bacteria throughout your system. You will turn your shower on and breath the mist. Then you'll get sick some time later. You'll develop a cough and go to the doctor. He'll give you some drugs that don't work becuse he doesn't know what you have.

People in the past died from legionella and people would say they died of pneumonia. They still say that unless someone looks.

I'm disappointed to see this forum not warn of this.

 

[Twowaxhack]

Not a nice outcome.

Do not cap lines that are still hooked up to your plumbing system.

LEGIONELLA

Those capped lines are still hooked up somewhere. They will grow, and slowly distribute, disease causing bacteria throughout your system. You will turn your shower on and breath the mist. Then you'll get sick some time later. You'll develop a cough and go to the doctor. He'll give you some drugs that don't work becuse he doesn't know what you have.

People in the past died from legionella and people would say they died of pneumonia. They still say that unless someone looks.

I'm disappointed to see this forum not warn of this.

That’s a tad bit dramatic. Sure it’s good to disconnect old lines but it’s not a death sentence.

At the temps that are recommended legionella can grow anyway. It can also grow in showerheads, especially plastic ones.

The Aria hotel had an outbreak shortly after it opened. It was caused by low water temps. They mitigate now every so often, it’s an ongoing problem. Usually only people with immune deficiencies get sick from the strain that grows in a treated water supply.

All legionella is not equal.

But sure, it can be deadly. But so can steak if you choke on it.

 

[havasu]

A serious question, but with chlorinated water, doesn't it mitigate your chances of Legionella?

 

[JG plumbing]

Chlorine no. If you've ever owned a pool you've seen bacteria grow in chlorinated pools. Legionella included

 

[JG plumbing]

No drama. It's just plumbing.

 

[Twowaxhack]

Everyone’s going to die......
https://legionellacontrol.com/legionella/dirty-shower-heads-deadly/amp/
Technically JG Plumbing is correct. Dead ends should be terminated. I’m just not willing to go as far as he does with the warning on this particular situation.

 

[Twowaxhack]

That might be part of a solar loop and he actually just eliminated it all from his system. He might’ve done himself a favor. Looks like he didn’t connect 2 lines, those could be an independent loop.

Both come out of the wall down low. One went to the top and the other went to the bottom. That’s a loop.

The OP also said the valves on these two pipes where turned off. So it’s essentially the same now as before he removed the heater except now they’re not connected to the heater.

 

[matt.mena]

If in doubt, solder on a male adapter. Thread on a cheap boiler drain to test if this line fills with water when the pressure is on. After the test, thread on a stainless cap.

If it was me, leave the price tags on the boiler drains and don’t scratch them up. After the test, return them to the store, clean.

 

[bartleyhs]

You need to add these components to the water lines so you can flush the system with vinegar. If you dont ever service it, it will be shorted lived.
note: I have heard the PRV is not necessary on a tankless (would like to hear what the pros here have to say about that), but the other valves are for sure because you have to occasionally flush it out.

 

[gnr5]

Wow this escalated quickly! I haven't capped them yet, that was my weekend project. I guess I'll leave it as is