The project
A 2004 two-story home in the Meadowmont neighborhood of Chapel Hill with a 50-gallon natural gas tank water heater in the garage that was 18 years old and had started leaking from the bottom. The slow drip had been going for a week before the homeowner noticed a damp spot on the garage floor. The anode rod was long gone, and the tank lining had corroded through.
The homeowner didn’t want another tank. The household had four people and two full bathrooms, and the 50-gallon tank had never been able to keep up with back-to-back showers during the morning rush. They wanted a tankless unit that could deliver continuous hot water without running out, and they wanted the old tank out of the garage to reclaim floor space.
The complication was electrical. The existing tank water heater was a natural gas unit with a standing pilot — no electrical connection at all. A modern tankless unit requires a dedicated 120-volt circuit for its electronic ignition, flow sensors, and control board. There was no outlet near the installation location, and the nearest circuit was already loaded. We’d need to run a new dedicated line from the panel.
What we did
- Drained and removed the 50-gallon tank — disconnected the gas line, water connections, and flue, drained the tank, and hauled it away for recycling
- Installed a Rinnai RU199iN tankless water heater — wall-mounted in the same garage location, 199,000 BTU input, 0.96 Uniform Energy Factor, capable of delivering 9.8 GPM in Triangle-area groundwater temperatures
- Upgraded the gas line — the existing 1/2-inch gas line to the old tank couldn’t support the BTU demand of the tankless unit. We ran a new 3/4-inch gas line from the manifold to the unit, with a new sediment trap and gas shutoff valve
- Installed a new stainless steel vent — Category III stainless steel vent pipe through the garage wall, replacing the old B-vent flue that went through the roof. The direct-vent configuration is more efficient and eliminated an unnecessary roof penetration
- Connected the water lines — installed new stainless steel braided connectors on both hot and cold supply lines, with isolation valves on each side for future servicing
- Installed a dedicated 120-volt circuit — ran a new 15-amp circuit from the main panel to a single-gang outlet behind the unit, on its own breaker, labeled in the panel directory
- Programmed the unit — set the output temperature to 120 degrees, configured the recirculation timer for the morning and evening peak hours, and walked the homeowner through the control panel
- Flushed the new system — ran all hot water fixtures in the house for 10 minutes to purge the old tank’s residual sediment from the supply lines
Trades involved
This project required two of our three licenses:
- Plumbing (NC #P1-22847): Water heater removal and disposal, tankless unit installation, gas line upgrade (3/4-inch from manifold), venting, water line connections, isolation valves, sediment trap, system flush, and programming
- Electrical (NC #28-LA-9214): Dedicated 120-volt circuit from the main panel, new outlet installation, breaker installation, and panel directory update
Both the plumbing and electrical permits were pulled through Orange County. Both inspections passed on the first visit.
Timeline and budget
- Duration: 1 day — arrived at 8:00 AM, the old tank was drained and out by 9:30 AM, the new unit was mounted and connected by 1:00 PM, the electrical circuit was run by 2:30 PM, and final testing and programming were complete by 4:00 PM
- Budget: On budget — the final invoice came in within the written estimate
- Crew: One plumber and one electrician, working in parallel after the old tank was removed
- Permits: Plumbing and Electrical — both passed first inspection
- Disposal: The old tank was hauled to a metal recycling facility the same day
The one-day timeline was possible because we had the Rinnai unit, gas pipe, vent materials, and electrical supplies on the truck before we arrived. When a water heater is leaking, homeowners can’t wait two weeks for a back-ordered unit. We stock the three most common tankless models for same-week installation.
The result
Continuous hot water for a family of four, mounted on the wall instead of taking up 4 square feet of garage floor. The Rinnai RU199iN only fires when a fixture calls for hot water, so the homeowner stopped paying to keep 50 gallons of water hot 24 hours a day. The recirculation timer means hot water reaches the upstairs master bath in under 10 seconds during peak morning hours.
The gas line upgrade ensures the unit gets the fuel volume it needs at full firing rate. The dedicated electrical circuit means the unit’s electronics are protected by their own breaker and won’t trip if someone plugs a shop vac into the garage outlet. And the direct-vent through the wall eliminated an old roof penetration that was a potential leak point.
A water heater replacement isn’t glamorous, but it touches three systems — gas, water, and electrical — and every connection matters. A tankless unit installed with undersized gas pipe will short-cycle. A unit without a dedicated circuit will lose power when the garage circuit is loaded. We handle every connection because we hold the licenses for every connection.