# Often asked: What Size Gas Line For Tankless Water Heater?

## Do tankless water heaters require larger gas lines?

Tankless water heaters provide hot water on-demand. Gas units require a gas line, adequate combustion air, a vent to remove combustion gas and an electrical outlet to power the unit. While they last longer than tank-style water heaters, they are more costly to install and often require upgrading your gas line.

## How many BTU can a 3/4 gas line carry?

Total piping length = 84 feet (use Table 3 @90 feet) From a to b, demand = 38,000 + 35,000 + 30,000 = 103,000 BTU/hr; use 3/4″ pipe From b to c, demand = 38,000 + 35,000 = 73,000 BTU/hr; use 1/2″ pipe or 3/4″ tubing From c to d, demand = 35,000 BTU/hr; use 1/2″ pipe or 5/8″ tubing From c to e, demand = 38,000 BTU/hr;

## How big of a gas line do I need?

Section 1, supplying outlets A and B, or 35 cubic feet per hour requires ½ inch pipe. Section 2, supplying outlets A, B, and C, or 94 cubic feet per hour requires 3/4 inch pipe. Section 3, supplying outlets A, B, C, and D, or 230 cubic feet per hour, requires 1 inch pipe.

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## Will a tankless water heater work with a 1/2 gas line?

Rinnai Tankless Water Heaters typically require a 3/4″ gas line to provide a sufficient gas supply to the unit’s burner. However, if there is sufficient pressure and the gas line is short enough, there are some cases where a 1 /2″ gas line can be used, which is the most common size used in the United States and Canada.

## Can a gas line be too big?

GAS PIPE SIZING You can flow only so much gas (or water) through a given pipe size, so restrictions will manifest themselves as a lack of pressure or volume. Sizing a gas line is not too difficult.

## How do you calculate BTU for a gas line?

To obtain the cubic feet per hour of gas required, divide the input of the appliances by the average Btu (kW. h) heating value per cubic foot of the gas. The average Btu per cubic foot in the Bay Area is 1,100.

## How many Btus can a 3/4 copper pipe carry?

3/4″ Pipe = 3.5 GPM = 35,000 BTU/hr. 1″ Pipe = 7.5 GPM = 75,000 BTU/hr. 1-1/4″ Pipe = 12 GPM = 120,000 BTU/hr.

## How far can I run flexible gas line?

The flexible connector length usually is limited to 3 feet except for gas ranges and clothes dryers. For these appliances, 6 feet generally is allowed. Splicing or joining connectors with nipples often is prohibited.

## How far down are gas lines buried?

Main lines are usually found at least 24 inches deep, while service lines are usually 18 inches deep. The current depth of an electric or natural gas line can be different than when it was first installed.

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## What happens if gas line is too small?

IF the gas line were too small, the burner AND pilot would go out, and then you would not have enough hot water until your relighted it. 2. An indirect heater does NOT get “free heat” and if the boiler is not adequate for the heating AND hot water demands the performance will be less than desired. 3.

## What size gas line do I need for a 22kw generator?

A 3/4” line will feed alot of appliances. The secondary regulator at generator drops the pressure for appliance. It has a regulator at the tank and then goes to this 3/4″ black hose which then goes down to a yellow 3/4″ plastic pipe.

## What is the downside 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.

## What size tankless water heater do I need for a family of 5?

In short, a family of 5 would need a 10 GPM gas tankless heater or 27 kW electric tankless heater if you live in the northern part of the USA, where the input water has a lower temperature. The tankless heater has to work extra hard to bring the water temperature up to 110˚F or 120˚F.