How to Install tankless water heater?

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Installing A Tankless Water Heater

The Tankless Water Heater – Hot Water On Demand

The tankless water heater does not heat up a full tank of hot water every time you turn on the hot water faucet. Tankless water heaters heat water only when a hot-water faucet is opened. This type of water heating system is also known as “on-demand” water heating.
A tankless water heater usually costs significantly more than a standard tank water heater, but within three to five years, you usually save in energy costs enough money to pay back the investment.

And then there’s the main advantage of a tankless water heater: you will always have enough hot water for all your needs. Make sure you purchase a model that is big enough to provide all the hot water you will need.

Tankless water heaters are rated up to 200,000 BTUs. They are capable of heating up to 9.5 gallons of hot water per minute, and can supply enough hot water for two or three faucets – including shower faucets – or appliances simultaneously.

Some units are large enough to supply your whole house with hot water. There are also smaller “point-of-use” models that are cheaper to buy and are intended to supply hot water in a single location, such as a bathroom. These smaller units can often be concealed in a cabinet.
This article describes the step-by-step process to install a gas-fired condensing tankless water heater. We have chosen to install a condensing unit because it is more efficient than non-condensing units.

Install water heater
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Gas-Fired Or Electric?

A gas-fired device will require that you run two PVC vent pipes out of the wall or up to the roof. Electric models are also available, and these do not require ventilation. If you prefer to use an electric unit, it will have to be connected to a 240-amp electrical service box.
You will probably need a permit from your local building department, and if you do, your work will need to be inspected upon completion to be sure that you have installed it according to Code.

Select The Correct Location

Select the place where you are going to install the unit. It is usually a good idea to put it near the location of your old tank-type water heater. The unit must be installed close to the main cold-water supply pipe, and also near a hot-water pipe that leads to the home’s faucets and appliances.

Since this is a gas-fired unit, you will need to run a gas line. You will also need to run vent pipes out of the wall or up through the roof. If there is no electric power outlet nearby, you will need to install one. Installing the unit close to the old water heater’s location will minimize your need to run new water and gas pipes.

Tools & Materials

These are the tools and materials you will need to install a tankless water heater:

– Tankless water heater with thermostat.
– A drill with screwdriver bit and hole saw.
– Channel-type pliers
– A pipe wrench
– Tubing cutter
– A saw for cutting
– PVC pipe
– Propane torch
– A spirit level
– Electrical tools
– Pipe straps
– Screws
– PVC primer and cement
– Vent termination kit or roof jack.
– Copper supply pipe
– Solder and flux
– Black gas pipe with pipe dope
– Shutoff valves for water and gas.

The unit we are showing you how to install today is a gas-fired condensing unit.

Condensing units require two vent pipes, while non-condensing units need only one vent pipe. Vent pipes run outside the house and must be oriented at a downward slope. There are connections and valves for gas supply, cold-water supply, and a hot-water line to the house. When installed, the unit can be plugged into a 120-volt
electrical outlet.

How to Install a Tankless Water Heater

Select the correct location for the unit

Position the water heater where you can easily access it for servicing. Make sure you keep the unit away from combustible materials. Securely mount the unit to a wall using the brackets provided, and make sure you drive the screws into studs. If your wall is brick or stone, use masonry screws or lag screws with shields.

Plan paths for the exhaust vents and air intake

Plan the path for the exhaust vent pipe and the air intake pipes. These pipes must exit the house at a code-approved location, and if the exit location is a house wall, the distance from windows and eaves must meet code requirements. Then cut the PVC pipe and assemble with fittings, using primer and cement. On the air intake pipe, install a condensate drain fitting at a convenient point for running the drain tube to a floor drain.

Run the pipes out the house

Now run the pipes out of the house. Make sure all horizontally-run pipes are sloping slightly downward, and support pipes with straps. Using the parts from a “termination kit,” cut two holes for the pipes, slip on interior flanges, and then run the pipes through the flanges and out the wall. On the outside, attach a termination cap with screws. Be sure to caulk the edges.

Venting through the roof

If venting out a wall is not feasible, you may need to run the pipes up and out the roof. In this case, all horizontal runs should be sloped upward, so condensed water runs back into the water heater. In the attic, join the two pipes together with a Y-fitting. Run the pipe out the roof, slip on adjustable roof flashing, cut the pipe to the approved height above the roof, and add an approved cap to the top of the pipe.

Hook up the cold-water connections.

Now hook up the cold-water connections. If your house has copper piping, do not use heat to sweat pipes or fittings that are connected to the tankless heater, or you could damage internal parts. Buy the service valve kit made for your unit. Install a cold-water shutoff valve prior to the connection parts. Connect the cold-water parts. If you sweated copper, allow the pipes to cool. Then connect the pipe to the unit’s valve.

Run cold water and check it

Turn on the valves to run cold water briefly through the unit, making sure the water flows freely. Close the unit’s shutoff valve, then remove and clean the water heater’s internal filter. If there is significant debris present, repeat this procedure until the debris is gone.
Connect the other parts

Now connect the other parts of the service valve kit, including another valve for the hot water. You will also need to install a relief valve. Extend the relief valve’s pipe down to a point where it can run to a floor drain. Then run a drain tube from the unit to a floor drain or utility sink.

Connect to the house’s hot-water line

Now connect the unit to the hot water line. You should make provision for a drain valve, so it can be drained when it needs to be serviced. As with the cold-water line above, if the pipes are copper, do not heat pipes or fittings while they are connected to the heater.
Hook up the gas connection

Now hook up the gas connection. Working with black gas pipe, install a gas shutoff valve just below the unit to trap sediment. Then install a union: this will enable you to easily disconnect the pipes for servicing. Then connect the other pipes. Make sure to include a vertical drip nipple. Then turn on the gas, and test with leak detector solution to make sure there are no leaks.

Connect the Thermostat

Now connect the thermostat. Connect two-wire thermostat cable to the unit, and run it to a convenient location from which you will be able to control the water heater. Now attach the thermostat’s plate to the wall and run the cable through it. Then attach the wires to the back of the thermostat’s cover. Now snap on the cover.

Test the Unit

Now test the water heater. Turn the water supply back on, and plug the unit into an electrical receptacle. You will want to make sure you know which circuit breaker controls the new water heater. When there is high demand for hot water, say from a faucet or an appliance, the water heater will turn on automatically and an electric spark will ignite the gas.

Program the Thermostat.

Now program the thermostat. Turn off the gas and water to the water heater by closing all the shutoff valves, and follow the manufacturer’s instructions for setting the water temperature. Turning the temperature down will save energy costs, but a minimum temperature of 85°F is recommended to keep water safe from bacteria.