# The things we do for friends...or hoping a used tankless heater will work!



## hroark2112 (Apr 16, 2011)

So I get a call from a friend, his basement is flooded. His 15 year old electric water heater is tripping the breaker, probably because the water is up to the upper thermostat inside the case. He found a used Rinnai tankless system on Craigslist, and has no clue how to install it. But, of course, he wants to help. Luckily for him, I had an electric water heater in my garage that I wasn't using, so I installed it for him to get him out of hot water (and in hot water!) with his wife.

The fun part is that the house is old, and the floor joists are all really dry, so I tried to do as little soldering as I could in the ceiling. The tough part was the tie in to the cold water, I didn't know how bad it was going to be and I set it up too close to the wood.

Here's the system as he got it. There's no way it was inspected before, it only had 1/2" gas run to it with a 3/4" x 1/2" reducer on the gas inlet.










Here's the tie-ins to the main & piping to the heater:



















Here's the system as I installed it. 










I've still got to run the T&P drain to the outside, and I hadn't yet installed the recirc line to the pump yet. I ran a 1/2" PEX recirc line to the far end of the house and he's putting the pump on a timer. Part of his "help" has been that he's doing all the electrical, hung the wood on the walls to hang the heater, and he drilled the hole in the outside for the vent. He still hasn't finished the electrical, so the old heater is still running.

Here's the gas piping and vent outside:











The system actually worked when I started it up, luckily!! I was concerned that the heater wouldn't work.

Let the beatings commence


----------



## rocksteady (Oct 8, 2008)

If that's a 48" flourecent light bulb, you might have your exhaust too close to both windows. 







Paul


----------



## hroark2112 (Apr 16, 2011)

That's the old pipe, not a bulb.

I had to look to figure out what you were talking about!

By the installation manual, you can't be less that 1' to the window in the US.


----------



## Protech (Sep 22, 2008)

What a waste of money. That first install looks like absolute garbage DIY.

What was the point of going gas tankless when you have all of that uninsulated copper recirc piping and electric tempering tank? You are loosing gobs of heat in that recirc loop that is being heated with expensive electricity. the standby losses and electrical costs will surely eat up if not exceed any savings that would have been realized by the tankless unit. I don't see the point.......


----------



## hroark2112 (Apr 16, 2011)

He's going to insulate the pipes himself. 

The first installation was by a plumber I know...he doesn't own a torch, can't solder, all he does is PEX. Even his shower valves are 100% PEX & sharkbites. I'm not against PEX, but I prefer copper, especially in this kind of case.

Once the pipes are insulated, that will help. The recirc pump probably will be off after a month, both bathrooms are right above the water heater, I can't see the guy running the tank & recirc pump for the kitchen & laundry. It's piped in though.


----------



## markb (Jun 11, 2009)

...Black street 90 on the 3/4 x 1/2 reducer caught my eye on the initial install lol


----------



## hroark2112 (Apr 16, 2011)

markb said:


> ...Black street 90 on the 3/4 x 1/2 reducer caught my eye on the initial install lol


...and no union between the shutoff valve & the unit...


----------



## OldSchool (Jan 30, 2010)

Looks like your termination is to close to the regulators


----------



## 1703 (Jul 21, 2009)

Isn't the return supposed to go into the tank heater and not the thankless?


----------



## GREENPLUM (Jul 27, 2008)

why didnt you run the recirc into the tank?


----------



## hroark2112 (Apr 16, 2011)

OldSchool said:


> Looks like your termination is to close to the regulators


It is 36", almost dead on. 

I still need him to paint the exterior piping. Don't need it rusting!


----------



## hroark2112 (Apr 16, 2011)

GREENPLUM said:


> why didnt you run the recirc into the tank?


Good question. 

I'll have to research that a bit. I've only done one other tankless system with a recirc line, but it was a very different system.


----------



## GREENPLUM (Jul 27, 2008)

vent pipe upside down


----------



## GREENPLUM (Jul 27, 2008)

no condensate drain/tee

looks like the floor joist got cut in half? 

i cant tell


----------



## smoldrn (Oct 4, 2010)

Recirc line on a Rinnai should be 3/4.


----------



## OldSchool (Jan 30, 2010)

hroark2112 said:


> It is 36", almost dead on.
> 
> I still need him to paint the exterior piping. Don't need it rusting!


That would make each brick over 18" long :blink:


----------



## Bayside500 (May 16, 2009)

hroark2112 said:


> He's going to insulate the pipes himself.
> 
> The first installation was by a plumber I know...he doesn't own a torch, can't solder, all he does is PEX. ..................................


sorry, but that "plumber" is not a plumber if he can't even solder LOL


----------



## Bayside500 (May 16, 2009)

we hard pipe the gas to our tankless installs


----------



## Plumb Bob (Mar 9, 2011)

hroark2112 said:


> Good question.
> 
> I'll have to research that a bit. I've only done one other tankless system with a recirc line, but it was a very different system.


You should request a schematic from Rinnai (or look in installation manual) on how to circulate hot water. Water should not circulate through tankless wh, it should circulate through slave tank on a loop and only draw hot water from tankless when there is a demand.


----------



## rvaughnp (Nov 19, 2009)

Keep in mind about the heat loss when using a 5 gallon 110v 1500 watt element water heater as your heat source... 


> Heat loss in un-insulated ¾” copper piping:
> 
> (30 BTU’s per hr x per ft) = (total BTU loss)
> 
> ...


I got this formula from Noritz. I have used it several times to see if a 5 gallon heater would work or do i go through the tankless. In a nutshell, the heater has to be able to keep up with the heat loss of the hot water system from the time it leaves to the time it returns. Insulating the whole line will help this tremendously.
I tried the 5 gallon heater on a (2) 100' run slab house and it wouldn't keep it hot. You may have shorter run.
Most manufactures will allow the recirc line through the tankless, they just drop the warranty to a few years. It beats the copper heat exchangers to death. Which is reason enough not to do it.

Also, the 5 gallon heater is used as a buffer tank on other manufactures install guides. It stops the cold slug that sometimes occurs with tankless.


----------

