How to Install Outdoor Tankless Water Heater Propane

A tankless water heater propane is a viable option if you are looking for a new hot water system for an RV or a travel trailer. These heaters can also be used for properties with limited or no access to mains electric and gas supplies. The propane heaters take up limited space, are relatively portable and the amount of propane used can be varied to suit how much hot water is required. With a few essential tools and by following installation tips it should be straightforward to fit a new propane heater wherever hot water is needed. The exact installation process varies depending on the place the heater will be fitted.

Picking the Best Outdoor Propane Tankless Water Heater on the Market

  • Endless Hot Water: Our tankless hot water heaters let you enjoy unlimited hot water flow throughout the house with a compact and durable design that fits your home and lifestyle
  • Energy and Space Efficient Tankless Gas Water Heater: This small hot water heater conserves energy, only heating when necessary; Enhanced scale detection lessens possibility of serious, long-term damage to unit
  • Optimal Water Pressure: This tankless water heater offers a high-performance hot water flow rate up to 5.3 GPM for a powerful, constant stream that serves up to 4 appliances at once
  • Professional Installation Recommended: Visit the Find a Rinnai PRO page on our website to locate a qualified technician in your area to install your tankless water heater; We do not recommend installing a water heater without a technician
  • Guaranteed to Last: 10-, 5-, and 1-year residential factory warranty for heat exchanger, labor, and parts, respectively

How to Install Outdoor Propane Tankless Water Heater?

To begin the process any older heaters, whether with tanks or tankless need to be removed. Once old heaters have been removed it is time to get the area prepared for the new tankless water heater powered by propane gas. Propane fuelled heaters are meant to be more flexible than other tankless water heaters, which is why they could be fitted to an RV or in a travel trailer.

install outdoor water heater

The key to successful installations is to prepare everything properly and safely. Remove all old heaters with care and cut the power before cutting wires or connecting wires together. When fitting a heater indoors you will need to make sure that it is vented to ensure safe use at all times. The propane gas needs to be stored safely and connected properly to the heater for the water to get hot.

You will need a screwdriver, a wrench, and union fittings for installing heaters effectively.

How to Install Indoor Propane Tankless Water Heater

The tankless water heater needs to placed where the previous heater was, or in a new place if this will be the first time that a water heater is being fitted. These are the steps:

* Start the process by switching off the mains water supply

* Splice into the pipes connecting the old heater to the water supply

* Remove the previous water heater and replace it with the new tankless water heater

* Use an iron pipe to link the propane gas tank to the tankless water heater

* Link the pipe to the tank with a union fitting

* Connect the copper pipes to the heater and solder into place

* Check the pipes to make sure that there are no leaks

* Switch on the propane and connect the heater to the electricity supply

What is the Difference Between an Outdoor and Indoor Tankless Propane Water Heater?

The most important difference between outdoor and indoor tankless propane water heater is that indoor water heaters need to have an air vent. Outdoor heaters are vented by virtue of being outside.

Another difference between outdoor and indoor tankless water heaters is that indoor heaters need to have more space to be installed into.

Furthermore, condensation is another reason for outdoor and indoor tankless water heater being different from each other. Indoor heaters create more condensation than outdoor ones even with ventilation.

How to Install a Propane Tankless Water Heater in RV

* First of all make sure that you have union connections

* Pick the right position for your tankless water heater

* Check the instructions before fitting

* Remove old heater if there was one

* Connect the pipes to the heater and the propane bottle

* Fill the tankless water heater

installing outdoor propane water heater

How to Install a Propane on Demand Tankless Vent less Water Heater in a Travel Trailer

To install propane on-demand tankless and vent less water heater in a travel trailer you will need to disconnect the old heater first. Then connect the wires to the tankless water heater and connect to the propane bottle. Make sure that none of the pipes are leaking and that the wires are fully connected.

Best Heaters For RV and Travel Trailer

  • 6 gallon water tank
  • 12,000 btu rating, With Insulation: Yes
  • Weight: 32.9 lbs
  • D- 12 Volt DC Direct Spark Ignition Gas Heating System

How to DIY Install Propane Tankless Hot Water Heater

To DIY install a propane tankless hot water heater you will to make sure that you have the best tools for the job.

For DIY tankless water heater installation, you will need a screwdriver, wrench, and union fitting. You may find that a soldering iron and extra copper piping could come in useful. Parts, piping, and tools should be readily available from DIY stores or hardware stores near you.

Remember that there are differences in tankless water heaters and therefore read the instructions before attempting to fit any heater. As the installation of heaters involves gas and almost always electricity be careful with fitting appliances.

A voltmeter is a must-have piece of equipment when you are installing heaters involving electrical wiring by yourself, as they show whether or not electricity is going through wires and appliances.

How Big of a Propane Tank Does a Tankless Water Heater Need

How big a propane tank a tankless water heater needs can vary depending on where the heater is being fitted and how much hot water is required. A propane tankless water heater will be considerably smaller than traditional tank water and smaller than a tankless system powered by either mains electricity or gas.

How big the propane tank needs to depend on long the heater is going to be used for and by How many people. If one of two people is going to stay in an RV for the weekend then the smallest tank will do the job. On the other hand when a family of 4 or 5 is staying in a travel trailer for several days then it would be better to get the largest propane tank to make sure that there will be enough hot water.

How to Fill Tankless Propane Water Heater

Once the tankless water heater has been connected to the water supply, the electricity is on and it is wired to the heater then it is time to start running the water.

Within a minute or so of the tankless water heater being switched on there should be enough hot water to meet everyone’s needs for bathing, washing, and doing the dishes.

You should only have to use a small amount of water for it to be warmed up by the heater itself.


The installation of a tankless water heater propane tends to a straightforward process depending on where it is been fitted. Generally, the old heater needs to be removed before fitting the new tankless water heater. Having a propane fueled tankless water heater makes it more potentially more portable than heaters powered by electricity or the mains gas supply. Buy small propane tanks if using the heater lightly for a couple of days, and a larger tank if more people are staying over for a longer amount of time.

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David: Penn State-educated Mechanical Engineer and Business-savvy Fluid Dynamics Specialist. Balances family plumbing business support with a thriving engineering career at a top, undisclosed company. (they want it that way) I help Will with plumbing and HVAC needs on his Real Estate.

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