How To Install: Tankless Gas Water Heater
Preparation
For this installation, Ben Goheen, a master plumber with over 10 years of experience, is replacing a customer’s gas water heater tank with a tankless gas water heater using SharkBite and Eastman products. Here's what you’ll need to install your tankless water heater:
Products:
- Eastman Steel-Flex Gas Connector
- Eastman Mini Stainless Steel Expansion Tank
- SharkBite Tankless Water Heater Connection Kit
- SharkBite Max Push-To-Connect Fittings
- SharkBite Max Depth & Deburr Tool
- SharkBite Pro PEX Cutter
- SharkBite PEX-a
- SharkBite Expansion Poly Fittings
- SharkBite Expansion Sleeves
Supplies Needed:
- Sharpie
- PVC pipe
- PVC primer and glue
- Hammer and drill
- Teflon tape
- Pipe dope
- Two adjustable wrenches
To start the installation, turn off the gas supply valve so you can safely disconnect the gas line from your current water heater. Then, disconnect the vent and cap it off since you’ll be upgrading to a more efficient vent. Next, decide the best location for your tankless water heater and drill the mounting bracket provided to the wall. In Ben’s installation, he needed to drill a wooden 2x4 into the basement framing for a secure installation.
Next, note the gas, hot water, cold-water supply, cold-water inlet, cold-water filter, recirculating pump, condensate trap, and drain. Since this tankless water heater has an internal recirculating pump, leave the recirculating pump location plugged.
First, prep the hot and cold-water inlets by applying Teflon tape in the same direction your fitting will go, which is clockwise in this case. Once wrapped, apply pipe dope to the edge of the inlet and do this for both the hot and cold lines.
To prep the gas supply, thread the female adapter from your Eastman Steel-Flex gas connector onto the supply and tighten with an adjustable wrench. Now it’s time to finish prepping the hot water line using the SharkBite Tankless Water Heater Connection Kit. Use the adapter from the hot valve and tighten it onto the hot water supply with two adjustable wrenches. Make sure to tighten it at an orientation that will allow you to install the relief valve. Then, apply Teflon tape and pipe dope to the relief valve and use your wrenches to secure it to the adapter. To finish prepping the cold inlet, secure the cold valve and its adapter with two adjustable wrenches.
After prepping your tankless water heater, mount it to the bracket you secured to the wall earlier. Use another 2x4 at the bottom of the tank to secure it completely to the wall.
Relief Line and More
Now it’s time to install the relief and condensate lines. To start, install a drain line to the relief valve either by using new pipes and fittings of your choice or, in this case, reusing some of your pipe from your old tank. In this installation, the drain line has a valve at the end since the line cannot drain by gravity alone. This depends on your setup, so examine how your line will be oriented to determine if you need a valve.
Before getting too far into creating the relief valve line, create a line for your condensate drain, orienting it so it can drain by gravity. Then, go back and finish installing the line from your relief valve. In Ben’s installation, he ran out of plastic fittings, so he used a SharkBite Max fitting to finish the job. Keep in mind, you always need to use the SharkBite depth and deburr tool to measure and mark your pipe, so you know how far to push the fitting.
Gas Line
Once you have finished both the relief and condensate lines, now you can move on to the gas line. Apply pipe dope to your pipe and fittings and use an adjustable wrench to install the Eastman Steel-Flex gas connector. Then, bleed the air out of the line by adding the sediment drip leg pipe to the line. To do this, apply pipe dope to the sediment drip leg and the cap and tighten the leg to the line. Then, loosely thread on your cap, turn the gas on, and smell for gas. Once you smell pure gas, tighten the cap onto the drip leg.
Water Supply Lines
Now you can add your hot and cold supply lines. Note that some building codes require a minimum length of copper pipe to run directly from a water heater, so check your local building codes and manufacturer specifications to ensure compliant installation.
In this step, Ben ran two feet of copper from the hot and cold outlets to the existing water lines. To do this, start by cutting around four inches of copper pipe for both outlets and use the SharkBite depth and deburr tool to deburr the pipes and to measure the correct insertion depth. Then, push your SharkBite Max 90-degree elbows onto the copper pipe and run the remaining length of copper you need, making sure to deburr the pipe before installing.
For the rest of the installation, Ben used expansion fittings and PEX-a pipe. Although this is not required, Ben chose this method because he trusts it as a fast, easy and reliable way to connect PEX-a pipes. To learn more about SharkBite PEX piping systems and to learn which methods to use for your installation, click below.
To continue the install, cut the length of PEX-a pipe you need with the PRO PEX tool. Then, prep your PEX-a pipe with the depth and deburr tool and use SharkBite Max fittings to transition from copper to PEX-a pipe. Once your PEX is connected, place an expansion sleeve ring on the end and ensure you are using the correct size.
Then, use an expansion tool to expand the pipe completely, then quickly connect it to either a brass or poly expansion fitting of the correct size. For the best results, push the expansion fitting into the expanded pipe until it hits the shoulder and allows the PEX to contract around the fitting completely. To finish the water line installation, repeat the expansion process until all connections are secure.
Thermal Expansion Tank
Tankless water heaters often require a thermal expansion tank, so Ben used the Eastman mini stainless steel expansion tank and prepped it before connecting it to the water heater. To prep the expansion tank, you need to match the psi of the tank to the psi of the PRV. In this case, the PRV was set to 60 psi, so Ben used an air compressor on the expansion tank to match it. Ensure that you have threaded on a SharkBite Max female adapter to the end of the tank, then prep a short piece of PEX pipe and push it onto the SharkBite Max adapter.
From here, assess your cold-water line and if you have one end of an expansion tee to connect to, use the expansion method. If you do not, you may need to use SharkBite Max fittings to make your connection. If you can use expansion, place an expansion sleeve ring on the end of the PEX pipe and use your expansion tool to expand the pipe. Then, place it on the remaining end of the expansion tee and wait until it fully connects.
Once your tank is fully secured to the cold-water line, install a PVC vent using a vent kit. Most of the time, you will need to purchase PVC pipes and glue in addition to the kit to make the connection. For this installation, Ben also needed a drill to cut part of the wall open to run the vent outside.
Running the Water Heater
Start by plugging in the water heater, then turn the water on slowly and ensure all valves are open. Then, use the display on the water heater to adjust the settings. For gas type, you can choose between natural gas or propane. Ben selected natural gas, but note that if you have propane, the water heater comes with a conversion kit, so if you have propane, you can field convert the heater to propane.
Then, select the correct elevation and select internal recirculation, and set the temperature to 140 degrees Fahrenheit. This temperature will allow you to have properly mixed water temperatures and allows the heater to use as minimal hot water as necessary. After setting up the unit, check that it is running properly by turning on the hot water around your home.