How to a Tankless Water Heater

We at Tankless Ratings strongly suggest getting a professional to do the installation and make sure they are familiar with Tankless models. Many old school plumbers will be against Tankless models as they are worried about change and are not familiar. How wrong they are. Also make sure you shop around as we know how plumbers are when it comes to billing. We received quotes of 200-1000 on the same unit from miscellaneous plumbing companies so be careful. Remember you will probably recover any expense on a tankless unit in energy savings in the first two years and have endless hot water. We have included some general information on an electric installation but each unit is different and will have different breaker, wiring and plumbing needs. Many will require wood, screws and mounting hardware as well but the Titan Tankless includes these items as well as a mesh filter at the input (cold) of the unit. Most units will require and upgrade to your wiring (thicker with an average of 6-8 gauge), a more powerful breaker (40 – 70 AMPs double pole and sometimes two of them). Make sure your home can support the unit electrically as they have an initial high current draw.
THINGS YOU WILL NEED: Tubing or PVC cutter (most will require a length of copper piping at the inlet and outlet about 18 inches prior to PVC), pliers, adjustable wrench, plumbing accessories, proper breakers, proper wiring, water hose, screw gun, bucket and don’t forget the beer (kidding). MAKE SURE YOU SELECT THE RIGHT MODEL as colder northern climates and areas with cold incoming water or higher water demand require more powerful tankless units. Make sure your breaker box can support your Tankless Water Heater. Many now will install a filter with their units but remember to only get a sediment filter as you don’t want your water pressure affected. A sediment filter can help keep out debris and thus extend the life of the tankless unit.

Steps to install your Tankless:

1. Make sure you have all the required plumbing, electrical and essential tools before you start. Most units come with detailed installation instructions.

2. Turn off your water and power for your home at the main source. Drain your old antique tank and make sure you look at the slime, rust and sludge that comes out that has been hitting your body all these years. Properly dispose of your tank and that does not include your neighbors yard, but unfortunately most of these end up in a landfill (not great for the environment).

3. Properly mount your Water Heater in a convenient spot and make sure you have some clearance from the floor and ceiling (about 15 inches at least). The Titan Tankless does come with mounting hardware and some may choose to build a base with 2 x 4’s but many can go right in the drywall. Make sure the unit is mounted upright, level and not sideways, upside down (yes it happens) or anything like that.

4. It is important that you go through your home and remove your shower heads, aerators and clean out the mesh filter and it is best to use energy saving devices with low GPM (gallons per minute) for these devices. A low flow shower head gets you just as wet and will save not only energy, but gallons of water every time you shower. All of these water saving fixtures can be picked up cheaply at your local hardware store or home depot.

5. Now its time to connect the wiring. Again make sure the MAIN POWER SOURCE is OFF! You are best to have someone familiar when dealing with electricity. It is essential also that you have the proper wiring (most will need upgraded wiring compared to your tank, usually about 6-8 gauge) and the proper breaker(s) in place. Many units will require two or more separate double pole breakers, and some just one double pole breaker. For example the Titan Tankless N-120 model requires a single 60 AMP double pole breaker with 6 gauge wire. Remember a double pole 30 AMP breaker is just that…a 30 AMP breaker. Many think because it is double pole it counts as two 60 AMPs breakers and this is a common mistake. If you were to use that the breaker would blow every time you activate your hot water. Each unit has different wiring specs so make sure you follow the individual water heater instructions. Once finished remember – DO NOT TURN THE POWER ON at this point. You must first get the plumbing done. This is another common problem and could possibly burn the unit out if there is no water running through it when it is activated.

6. Now we get to the plumbing. Again every unit has different requirements but if you are running PVC you must generally run a length of copper plumbing for about 18 inches or so from the cold and hot water inlet and outlet of the unit before connecting with the PVC. It is a good idea prior to connecting the plumbing to the unit that you run your water source briefly to make sure it is clear of any debris in the line. This is where the bucket and hose can come in handy. It is also important to make sure the mesh filter is installed at the inlet of the Tankless unit the heating unit to keep debris out in future use. Although not required it is not a bad idea to install small water filter (make sure you get one that is just to stop debris and does not affect water pressure). This further protects the internal components from sand, rust, and various sediment and can increase the life of the unit greatly. We advise this as internal flow switches on Tankless units are constantly turning off and on and over the years sand or rust could affect its operation. A 20 micron (8 GPM) is fine. Remember this is optional and not required. Also make sure you have a shut off valve prior to the Tankless unit as if there is ever a problem you can simply turn off the water supply, remove the unit and replace or repair it. It is also code in most areas but many neglect to follow that.

7. This is most IMPORTANT: As crazy as this sounds this is one of the most common problems we find with installations. Make sure you properly connect the inlet port (COLD) of your Tankless unit with your cold water line coming into your home. The outgoing port (HOT) then goes into your home (kitchen, bath, shower etc). You won’t believe how often people reverse this step and it causes all kinds of problems we don’t even want to get into. The Titan Tankless clearly marks the areas on the unit itself as this problem was so common it was required. Many others followed suit.

8. Once the plumbing is installed at the inlet it is a good idea (WITH THE POWER STILL OFF) to again run the cold water and make sure the lines are clear (bucket again). Then once plumbing to the outlet of the unit is done continue to run the water (POWER STILL OFF) again and make sure your aerators, shower heads etc are still off and go to each site and run the water to further flush out your homes pipes as well (watch out for flooding as there is no restriction). Once this is done you can reinstall the aerators, shower heads etc. Once all these steps are completed you can now, FOR THE FIRST TIME, ACTIVATE YOUR POWER. At not time prior should your power be turned on for safety purposes. Remember that if you activate your power during any critical installation phase you risk damaging the unit and worse you can get scalded as the water coming out of the Tankless unit is incredibly hot. You can now go to a shower and adjust your tankless settings to a comfortable range (this may require some tweaking). Again we recommend a professional do the installation. You have successfully installed your Tankless Hot Water Heater now and can now go take a shower for 2 hours. Remember you now have endless hot water!!

24 Responses

  1. I did my own installation of a Titan Tankless and wanted to point out that if you use a disconnect box make sure that you have the wires correct. There are two screws on each side of the disconnect and I put the wires from the Titan on the same side together where the two screws are and the breaker wires on the other sides two screw. THIS IS WRONG and I found out the hard way when I blew my main breaker (no damage). To make is easy the wires do not share the same side. One wire from the Titan goes on one screw on the left and the second wire goes on the other right side using only one of the two screws. The breaker wires would then go on opposite sides also in the remaing screws. I tried to post a picture of the correct wiring but it wont let me do it here. I hope everyone understands if they are installing themself.

  2. I wanted to pass on some installation tips that are important. I bought my Titan on Amazon from Tankless Store and they helped me figure it out.
    Before connecting your main water line make sure you get a bucket and let it run to make sure the pipe is clean. There can be debris in there and if it gets in the Titan it can be a problem. Once you hook up the line DONT POWER up yet and let water run through the unit for 30 seconds for the same reason. When hooking up power best to use a disconnect box and make sure you wire it correctly. I had the lines connected wrong (had the Titan wires on one side and panel wires on the other which is wrong) and customer support helped me fix that but it was 2 hours of wasted time. Just look at the instructions for the disconnect as the wires from your panel and the Titan from share the same sides on the disconnect.

  3. What about electrical requirements for these water heaters? I have an older home and not sure if I can upgrade to larger breakers and more power than my tank model. Also I don’t see much about gas models here, are they a good alternative?
    My service on my electrical panel is 200 AMPs. I was looking at the Titan N-160 model for my home and was not sure if I could support it here.

    1. You make a good point about checking your panel before purchase. If your panel is 200 AMPs than you would have no problem with the Titan N-160 model. This type of panel would support most tankless models with no problem so a good rule of thumb is that if you have 200 amps in an average size home you are good to go.
      If you are in a trailer, boat, small apartment many have 100 AMP service there. They make smaller models to accommodate this setting. Many larger boats have Titan Tankless models on them with great success.
      We do discuss gas models but are not big on them due to a huge recall for carbon monoxide poisoning and other safety issues. It is for this reason we prefer tankless.

  4. I am trying to decide which tankless model to go with but if I do the installation itself would that void the warranty? I am not a license plumber and just pretty handy. Thanks

  5. How important is a filter for installing these? I live in Georgia and have well water so I wasn’t sure what to do about that. One installer told me it is not needed and another recommended it. Also make sure you shop around for installers cause they price varies so much.

  6. Nice weblog over here! I’ll just wanna say thanks for the information. If you like to visit my website check out our website to please as we deal in your number one rated Titan Tankless Water Heaters

  7. I just wanted to let people know that some plumbers can charge crazy amounts to install these. Just shop around and make sure they are familiar with these tankless units as many are old school and dont believe in newer and better technology. You should not pay more than 250 for a standard installation. Thanks

  8. I just did an installation on a N160 Titan and it took about 5 hours total but that included removing the old tank. Some things I learned was that you need to upgrade the wire and breaker and you must use the compression fittings in the installation kit only. Before you install the incoming line to the Titan get a bucket and flush out the lines as there was dirt in mine from cutting the copper pipe and cleaning. After that run water through Titan with no power and make sure water is activated when you first turn it on.
    Can I post pictures on here? I see no way to do so.

    1. Thanks for the post. Yes it is really important to use only the compression fittings that come with the unit as they are designed specifically for that. Other fittings will leak or cause other issues. Purging the lines is also important as well.
      We are working on upgrades so users can post pictures and we will let you know.

  9. Can in install a Titan myself? My breaker panel is right next to where the unit will go and I have the tank water heater right there as well with all the plumbing. My husband and I are very handy so we thought we would try this. Can someone enlighten me on this? We are in South Florida and installing an N-120 model

    1. The Titan Tankless website recommends hiring a pro for this but as we know they can be way over priced for jobs like this. As your unit is close to your panel and existing tank it makes this much easier.
      If you are careful, and handy it should be no problem.
      First you need to drain your tank from the bottom valve and remove. Check out the junk you see the comes out of your tank and you will never want to use a tank again. Sludge, rust, slime and sediment will be coming out!. The most difficult will be to swap out your breaker to a 60 AMP double pole and dealing with the electrical. As always MAKE SURE THE POWER IS OFF FROM YOUR MAIN SOURCE AND ALSO YOUR MAIN PANEL. The breaker is easy to do as they slide or pop in and out so you would simply replace your Tanks breaker with the new 60 AMP and you need to run thicker wire 6/2 gauge to the new unit. If you are familiar with basic plumbing you should have no problem here. Remember you must have length of copper pipe at the inlet and outlet of the unit if you plan to use pex or similar material. Also make sure you connect the incoming cold water source to the marked COLD inlet on the Titan and the HOT line to the interior sources in your home. Yes people mess that up all the time. You can also use Sharkbite fittings to make installation easier and faster with virtually no soldering. Make sure you purge your plumbing lines when the original tank is removed and also run water through the Titan unit before power is turned on and open your faucets to get good flow. Once satisfied you can active the Titan.
      The units to come with more in depth instructions but we wanted to touch on some main ones. Some other important points are
      You can see a good installation photo here:

  10. Can you use pex for Tankless Installations? I had read you must use copper plumbing due to high heat production. This can create an installation issue for many people including myself.

    1. Yes you can use Pex, PVX or other similar material for a tankless unit. You just need a short length of copper plumbing at both the inlet and outlet of the tankless and then your pex will attach to the copper easily.

      This is not really an issue as attaching pex to the copper plumbing is actually easier than soldering copper lines together. As pex is flexible it also makes routing the pipes much easier so no worries

  11. Can you install a tankless model outdoors? My tank is currently outside my home with a small covering over it. It is leaking and covered in rust so I would really like to replace it.

    1. Almost all tankless models would need to be installed indoors or in extreme cases outside but in some form of enclosure that complete protects it from the elements.
      Keep in mind tankless units are about 80 times smaller than a tank model so you can probably just install inside a closet or somewhere near your electrical panel and plumbing connections.
      Please remember that leaks and rust on your tank model can lead to health issues with the water inside so please take care of that. Good luck!

  12. I want to install in my basement to save space so how would venting work with these type models? That could be an issue for me and why im hesitant to purchase.

  13. Can you set up a tankless unit to just do say one bathroom? I have a jacuzzi tub that I purchased along with a steam shower. Can I just get a unit to devote to that set up?

    1. The answer is YES. You can install a tankless model to run your entire home or you can get a custom set up where you set it up for point of use or for what you described above. Sounds like a pretty nice bath set up there and the tankless units are so small you can install it in say a closet adjacent to that bathroom or any convenient location as long as you have access to the plumbing and electrical for that area.

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At Tankless Ratings we do not receive any compensation from any tankless company, nor do we have any affiliate or Amazon links as 99% of other sites do. We just rank electric tankless water heaters based on performance, build and value. We have been rating electric tankless for over a decade.