Tankless Water Heater Recirculation Pump
 

Has anyone installed a Tankless water heater recirculation pump on their Rheem water heater outside? Looking for some options to get faster hot water. Is this a DYI or do you need a professional? Any recommendation on brands and how your experience was?

You need a special pump that has enough flow to start the tankless system. Call Mike Scott or another professional.

This recent conversation might help
https://www.talkofthevillages.com/fo...=recirculating

You do realize this will cause the tankless water heater to run much more often. IMHO, if this is a big problem, have another electric tankless water heater installed in the bathroom, figure on at least $1000. I saved a lot of money, I turn on the shower to full hot, count to 30, move the handle back to the normal shower position wait 5 seconds and the shower is ready.

Another thing you can do is to turn on the hot water sink faucet, which will reduce the 30 seconds to about 15 seconds or less.

The idea is to install the pump then have it controlled with a smart switch so you can turn it on or off with Google or Alexa with your voice.

The above 2 replies are excellent, I was thinking of the older timer based solution.

I have a pump on my old fashion hot water heater. The system circulates the hot water back to my tank in the cold water line. How would this work on a tankless system? The question is where does the cold water go that you are pushing out of the hot water line?

With a regular tank hot water heater you can buy and install the circulator pump on-line or at home depot. Very easy.

If you have a tankless system, this pump may not work because the tankless needs a certain amount of flow before it will turn On. That's why unless you know what you are doing, best to get a professonal to install it then you can add the wifi switch to control it with Google or Alexa.

Check the warranty. Mine says the warranty is void if a pump is installed. There are some that come with the ability to handle a recirculating pump.

2nd Small Tank Necessary
 

A Watts recirculating pump and a tankless water heater are not compatible for the reason there is no where for the water to "recirculate".

With a traditional 40-60 gal water heater, the Watts recirculating pump pushes hot water from the tank at low pressure through the hot water line. By reason of an innovative manifold that is installed at the faucet furthest from the water heater, the hot water being moved by the Watts pump goes into the cold water line and back to the water heater. In other words, it "recirculates" in a closed loop.

This only happens when all the cold water taps at all the faucets and showers are closed. If a cold water tap or shower is open, the valves in the manifold close and the water being pushed by the Watts pump does not enter the cold water line. It's an ingenious system and provides hot water at all the faucets and showers in the house within seconds.

To use the Watts pump with a tankless water heater, you will need to install a 2nd hot water heater after the tankless heater to serve as a reservoir of hot water which can then be recirculated by the Watts pump. Small tanks of this type are 7-10 gallons in size and are readily available at Home Depot and Lowes.

With a standard hot water heater, the Watts pump is an easy DIY or it can be installed by a handyman. Adding a second, small, tank after a tankless heater is more complicated and should, probably, be left to a plumber.

Buyers of tankless water heaters are often under the impression that they will have "instant" hot water. They will, but only at the outlet of the tankless heater. Just as with a regular water heater, the hot water from a tankless heater has to flow to the faucets and showers inside the house before there is hot water at them.

Install a Watts pump. You'll never regret doing so. One final piece of advice--in some houses in The Villages, such as our Magnolia model, the hot water line "splits" and goes in two directions after it enters the house. This requires a second manifold so that there is one at the end of each line. The extra manifold costs approximately $50.

You need much more than just putting a pump o the hot water line, you need all the plumbing that goes with it. If you stick a pump on the hot water line by itself, you will blow the line apart overtime time.
Also you don’t use the cold water line as the return line. If this was the case you would never have cold water.
A hot water recirculating system is 1 big loop of the hot water line with drops for each kitchen and bath. The water from the heater flows in a circle keeping the water at a temperature you program at the pump, not at the heater. If you set the water heater at 120 and the recirculating pump is set at 122, your water will run constantly because it’s trying to heat the water to something higher than your heater. Don’t do this. I always set my pumps to a temp of 3-5 degrees colder so the pump would shut off for periods and when we needed water, it was only a couple degrees off the max setting ofthe heater and we had instant hot water at every location

I have a friend in Fenney who has an instant hot water system and he had Mike Scott install a pump with the bypass device on his system. It's been working well for a couple of years now. It's conneced via a wifi switch connected to Google so it only runs when they need hot water.

You can’t do that because a tankless does not really store any hot water. It only works when you have a tank full of hot water.

Here’s an answer
 

Put one of these under the sink of your furthest faucet (usually the master). Fairly easy install for a DIY or simple for tradesman. I have installed these on all my homes.

The one below is an extra one I have advertised on Nextdoor.

Title should say, this may be an answer