The Importance of Proper Gas Line Sizing for Tankless Water Heaters and Multiple Appliances

The Importance of Proper Gas Line Sizing for Tankless Water Heaters and Multiple Appliances

When it comes to heating and gas-powered appliances, ensuring the correct gas line size is critical for both safety and performance. At Heat and Cool Brothers, we’re committed to providing expert advice and services to keep your system efficient, compliant, and safe. Here’s a look at what happens when an undersized gas line is used, especially with high-demand appliances like the Rinnai tankless water heaters (160iN or 199iN) alongside other household appliances like furnaces, stoves, and pool heaters.

Why Proper Gas Line Sizing Matters

Gas-powered appliances, particularly those requiring continuous fuel for heating water or air, are designed to work with specific gas line diameters. For instance, Rinnai’s high-efficiency tankless water heaters require a 3/4” gas line to ensure a consistent and adequate gas supply. Using a 1/2” gas line with a reducer (1/2” to 3/4”) might sound convenient, but it leads to several potential issues:

1.Insufficient Gas Flow

•Problem: The reduced 1/2” line doesn’t supply enough gas volume for high-demand appliances.

•Impact: Without adequate gas flow, the tankless water heater may struggle to heat water efficiently, leading to inconsistent hot water supply and possibly shutting down during high-demand periods.

2.Pressure Drops

•Problem: When several appliances (like your furnace, stove, and pool heater) draw gas simultaneously, the 1/2” line cannot maintain sufficient pressure, causing a drop.

•Impact: Reduced pressure not only affects your tankless water heater but also causes performance issues across all connected appliances. For example, your furnace may run less efficiently, or your stove may experience fluctuating flame heights.

3.Safety Risks and Code Violations

•Problem: Gas codes exist to protect homeowners from hazards associated with improper installation. The Ontario gas code (B149.1) mandates that each appliance is connected to a correctly sized gas line as specified by the manufacturer. A 1/2” line with a reducer does not meet these standards for high-BTU appliances.

•Impact: Installing an undersized line is a code violation, which could void your appliance warranties, lead to inspection failures, and create potential safety hazards, such as carbon monoxide leaks from incomplete combustion.

Understanding Longest Main Run (LMR) and Total Gas Demand

To determine the right line size, our technical team conducts an LMR (Longest Main Run) analysis, which takes into account:

•The distance of each appliance from the gas meter.

•The BTU load required by each appliance.

•The combined demand when all appliances are running simultaneously.

For a system with a tankless water heater, furnace, stove, and pool heater, calculating the LMR helps ensure that the entire system receives adequate gas supply at the correct pressure.

Code Compliance for Safety and Efficiency

Ontario’s natural gas code, particularly sections such as 6.9.3 and 6.9.4, emphasizes that proper gas line sizing is not just a recommendation—it’s a requirement. Appliances must have individual lines meeting their specified sizes to prevent pressure drops and ensure full, safe operation.

Using the correct gas line size means:

•Safe Operation: Prevents risks like carbon monoxide leaks from improper combustion.

•Efficient Performance: Ensures each appliance operates at its optimal capacity.

•Warranty Protection: Keeps appliance warranties valid by adhering to manufacturer specifications.

Call Our Technical Team for Expert Guidance

If you’re installing or upgrading gas appliances in your home, Heat and Cool Brothers is here to help. Our expert technicians can assess your setup, perform the necessary calculations, and ensure everything is up to code. Don’t compromise on safety or performance—reach out to us today for a consultation.

Contact Our Technical Team Toll-Free: 1 (855) 999-1660

For safe, efficient, and code-compliant installations, trust the professionals at Heat and Cool Brothers. Let us handle the details so you can enjoy peace of mind.