Yes 2psi on 1/2″ iron can deliver your stateted load a whopping 250 feet! You can use a 1/2 in regulator down to 7″ up to about 15 feet before the tankless. And reduce at the unit. Also check the tankless for acceptable input pressure, you may not need a reg but most likely you will.

How much gas pressure do you need for tankless water heater?

15-150 psi water pressure. 40 psi or above recommended for maximum flow. *For Propane, minimum inlet gas pressure is 8.0 in.

What size water line do you need for a tankless water heater?


A typical tankless water heater will need a ¾-inch gas line. However, if there is sufficient pressure and the run length is short enough, a ½-inch line may be sufficient with certain tankless water heaters, such as the Noritz EZ Series.

What is the minimum flow rate for a tankless water heater?

0.5 gallons per minute

What is the minimum flow rate required to operate a tankless water heater? Tankless water heater must be able to sense water flow in order to initiate operation. Most models will operate with flow rates as low as 0.5 gallons per minute. This is the lowest minimum flow rate in the industry and is an important benefit.

Do tankless water heaters run on natural gas?

The 3 most common fuel sources for tankless water heaters are electricity, natural gas and propane. An electric tankless water heater is designed completely different than gas models. However, a gas unit is designed to burn either natural gas OR propane.

Does a tankless water heater need a pressure regulator?

Gas-fired tankless water heaters will usually require a pressure relief valve, while electric on-demand water heaters may not. The manufacturers typically only require a pressure relief valve, not the combination temperature and pressure relief valve that is necessary for tank-type water heaters.

What is the minimum water pressure for a Rinnai tankless water heater?


Water Pressure (Min): 50. Water Pressure (Max): 150.

Does a tankless water heater need a 3/4 pipe?

Typically, tankless water heaters require a ¾-in. or 1-in. supply line.

Can PEX be used with tankless water heater?

PEX tubing may be connected directly to residential electric tank or tankless (instantaneous) water heaters, if the local code and manufacturer’s instructions allow. When connecting PEX tube to gas tank or tankless water heaters, the tube must be kept at least 6 inches away from the exhaust vent of the heater.

Can I use existing vent for tankless water heater?

Tankless units require 1/2″ or 3/4″ water lines and 3/4″ gas lines. Keep in mind that the new tankless heater cannot be connected to the existing exhaust pipe from your old heater. All tankless direct vent heaters require a stand-alone intake/exhaust system.

What are the disadvantages of a tankless water heater?

The primary disadvantage of on demand or instant hot water heaters is the upfront cost. The smaller units that you often see won’t produce enough hot water to serve most households. They’ll only serve one faucet at a time—a problem if you want to shower while the dishwasher is running.

Can a tankless water heater run a whole house?

Electric tankless water heaters can be installed in any location within your home with the appropriate hookups. Their compact size frees up valuable space within your home. For gas tankless water heaters you will need to utilize specific venting, which will impact where you can install throughout your home.

Is it better to get an electric or gas tankless water heater?

Efficiency / Operating Cost:
While gas tankless water heaters are certainly more efficient than their tank cousins, their efficiency usually peaks at 80-85%. Conversely, most electric tankless water heaters are 98+% efficient.

How do I increase the water pressure in my tankless water heater?

Tankless water heaters work by restricting flow until the water reaches the preset temperature, so if the flow is too low from your tankless heater, you may increase it by lowering the temperature setting, says BEC Green.

Do I need a backflow preventer on my tankless water heater?

Backflow preventers are now required by many plumbing codes to be installed in the cold water supply line from the street. Before the days of backflow preventers, the expanding water in the hot water tank could push backwards into the main water supply.

Do tankless water heaters need check valves?

Each tankless unit in North America must have the pressure relief valve installed per ANSI for all water-heating systems. When installing this valve, you must not plug it or install any reducing fittings, restricting the pressure valve from its normal operation.

What size expansion tank do I need for tankless water heater?

These tanks are small (1 – 2 gallons), but they can create high system pressure due to thermal expansion. If a tankless heater has an integral buffer tank, a thermal expansion tank should be included in the system design to prevent overpressurization.

How do you install a pressure relief valve on a tankless water heater?

Screw the valve into the port on the lower edge of the tankless heater by hand. Fit an adjustable wrench onto the flat portion of the valve and continue to tighten the valve clockwise. Stop when the valve is reasonably tight and the pressure-release lever is facing toward the outer edge of the tank.

Can you use CPVC for tankless water heater?

CPVC pipe and fitting materials have been used in hot and cold water plumbing systems in North America for 45 years and also have been used with tankless devices for over 25 years in Europe.

Can you use PVC to vent a tankless water heater?

In most cases, PVC makes a great venting material. It’s the least expensive option and is easy to install. And it’s a good reason to consider a high-efficiency condensing unit.

Can you use flex pipe for water heater?

You can use flexible gas tubes or water pipes for a gas water heater in most states. In states with earthquakes, they can even be mandatory. If your existing gas pipe has CSST (corroded stainless steel tubes) or has not been glued, the connection should be replaced right away.