Instant water heater - existing hot water line in - unit's hot line out to faucet

[Chuckiechan]

My problem is the hot water heater is quite a way from the kitchen. I don't want a tank less water heater as an additional "stand alone" hot water source.

My plan is to run the existing hot water line into the tank less's cold water IN side, and it's hot water OUT side to the faucet. Thus, hot water will immediately go to the "hot" side of the faucet. Eventually, the garage hot water will flow through it, and I presume a thermostat will prevent overheating.

My reasoning is this: I want hot water right away when I turn on the tap, rather than wait for the hot water to come from the garage hot water heater.

Can I do this? We keep our hot water at around 160 deg, I think... we don't have a need for scalding hot water.

Thanks in advance

 

[johnjh2o]

It will work. But the flow rate at the kitchen faucet will suffer. There are restrictors in electric tankless heaters to allow the water time to heat. You can get even better results by using a recirculating system that can give you instant hot water to all your faucets. Using your existing water lines.
Instant Hot Water Recirculating System - New Products - Watts

John

 

[Chuckiechan]

Ariston electric tankless water heaters point of use instantaneous 110 volt outlet hot water mini tank ...Click on proceed to link destination..

This seems to say you can use the "hot" as a supply line.

And how much do continuous hot water pumps cost to run for kitchen only? It's seems expensive to be continuously losing heat from your pipes all day long.

In the summer is really hot in Sacramento, and that heat is going somewhere in my house. That's my hang up with this, but I may still consider it.

 

[johnjh2o]

You don't have to run the pump continuously. They have a built in timer. Plus it is a very small motor that uses very little power. I would think far less then a electric heating element.

John

 

[havasu]

John is on the right track. A recirc system with a Grundos pump and timer will work perfect for your needs for pennies a day....well, maybe a bit more!

 

[green_machine]

I am in the same "boat" as Chuckiechan...I built a new home and plumbed for a recirculating system. I have two propane 50 gallon hot water heaters in series. The master bathroom is approx. 50-60 ft away. I was running the recirculating pump an hour in the morning and 1 hour in the evening. I had to cut the pump off due to the high cost of propane use. My solution was to install a small tankless hot water heater to provide instant hot water to the master bath. I have a two sinks, one tub and shower. My questions is how do i determine where to tie into in order to provide hotwater to all? My first thought is to turn on all faucets and see which one gets hot first...etc. I fear this may not be accurate as it is only me performing this task. Any help or insight would be much appreciated.

 

[johnjh2o]

My first question is why do you need two 50 gallon water heaters? The second question is do you have a dedicated recirculating line? I would think your high propane use would be more related to the amount of water your heating and not to running the recirculating pump for just two hrs. per day. As far a determining were to install a point of use heater we need to know how the home is piped. Can you see the piping or is your home built on a slab and the lines are under the slab?

John

 

[Chuckiechan]

I'd put it at the fixture you "get mad at" the most!

In my case, it was the kitchen sink. I determined I had 1.5 gallons of cold water in the lines, so I got a 2.5 gal unit.

 

[ua34plumber]

They're not "hot" water heaters, they're water heaters!!! Why would you heat hot water?!

 

[green_machine]

My first question is why do you need two 50 gallon water heaters? The second question is do you have a dedicated recirculating line? I would think your high propane use would be more related to the amount of water your heating and not to running the recirculating pump for just two hrs. per day. As far a determining were to install a point of use heater we need to know how the home is piped. Can you see the piping or is your home built on a slab and the lines are under the slab?

John

I run two 50 gallon water heaters in series to help reduce energy consumption. I need two because my wifes tub alone will drain 1 water heater. My house is built on slab with a recuilating system plumbed in. I figured out the routing of my plumbing by turning off the water at the house, drain water out at a sink shutoff valve, injected food coloring then turned water back on with all faucets open. I monitored which faucet the colored water came out first. So now that I know which sink starts with the hot water I will plumb that into my tankless unit and run the return back to the house...should work right?

 

[Chuckiechan]

So now that I know which sink starts with the hot water I will plumb that into my tankless unit and run the return back to the house...should work right?

Huh? I'm confused.

I think to get instant hot water at each outlet, you'll need an inline hwh at each outlet.

You are pushing cold, displacing hot in the inline hwh until the hot from the garage reaches the inline hwh and caused it to shut off.

Back to my example: I had 1.5 gals of cold water in my kitchen line, so I only needed a 2.5 gal hw system at the sink - enough to push hot water until the garage hwh water reached the inline hwh. The 2.5 was ~ $ 150.00 at Home Depot. This may be the way you should go.

Inline heaters are expensive and may not give you the flow you need, and most with a decent capacity are 240 volt.

 

[Chuckiechan]

I bought the Ariston GL 2.5 GL made by Bosch.

I hooked it up "in line", hot to faucet, cold in from hot water heater in the garage.

It works like a charm. Instant hot. It gradually drifts off a little to a little cooler as cold water mixes with the hot in the tank, but that's ok. Eventually, hot water from the outside heater takes over and it rises again.

I have it plugged into the same receptacle as my 5HP Badger garbage disposal. I have had no circuit breaker problems.

The hw heater pulls 12.5 amps @ 120V
The Badger pulls 6.9 Amps

I'd call the project a success and well worth the money ~ $ 160.00.

That is one major aggravation I don't have to live with any longer!

 

[jjansen28]

Hello,

I am too looking to install a 2.5 gal water heater under my kitchen sink..

I am curious how you connected the PT valve to an open drain?

I'd like to tie it into the dishwasher drain on the garbage dispposal, but I cannot install the tank high enough to get the proper slope..

 

[johnjh2o]

If your kitchen sink is on a outside wall you could pipe it through the wall to the outside. Don't connect it to any waste lines.

John

 

[jjansen28]

Unfortunatley, will not be able to cut a hole in my kitchen wall to drain the PT valve outside the house.

As many of these units have been installed under kitchen sinks, I would assume that there has to be a solution for draining them in to an existing waste line. Just like the dishwasher is drained.

Is there a reason you are saying to NOT drain into the waste line?

I have actually seen a picture on Amazon showing a bathroom vanity with a mini-heater installed. The PTV is just pointing to the bottom of the vanity!