A gas heater is the fastest way to warm a pool and the only practical way to bring a spa up quickly on a cool evening. What people do not see is the line behind it. A heater fed by a pipe that is too small, or a meter that cannot keep up, runs at a fraction of its output and short-cycles. Here is what a proper gas supply involves and the decisions that come with it.
Natural gas or propane
If the house has natural gas, that is nearly always the choice. It costs less per unit of heat, there is no tank, and no deliveries. The questions are whether the meter has the capacity and how far the run is to the equipment pad.
If the house does not have natural gas, and many Triad homes outside the city grids do not, propane is the alternative. The heater is ordered or converted for propane, a tank is placed, and a propane supplier fills it. Propane costs more per unit of heat and the tank has to be sized for the heater's appetite and the season, but it works anywhere a truck can reach. Heat pumps vs gas heaters is worth reading if the gas situation is complicated, because a heat pump needs only electricity.
Meter capacity
A pool heater draws far more gas than a furnace or a range. The utility sizes the meter for the house's total connected load, and a heater can push that past the meter's rating. When it does, the utility upgrades the meter, which involves a request, a visit and sometimes a wait. This is checked before anything is trenched, because a heater on an overloaded meter starves every other gas appliance in the house when it fires.
Pipe sizing
Gas pipe is sized by the load at the end, the length of the run and the pressure available. A long run to a pad at the back of a big lot needs larger pipe than a short one. Undersized pipe is the most common gas heater problem we see on existing pools: the heater fires, cannot get enough gas, and shuts down on a fault or runs weak. The gas contractor does the sizing calculation from the heater's rating and the measured run; it is not guessed.
The trench
Underground gas line runs in a trench at a required depth, in approved pipe, with a tracer wire for future locating, and is pressure-tested before it is covered. It is planned alongside the other utilities to the pad and with an eye to what it crosses. If the pool is being built, the trench goes in before the deck; retrofitting a line under an existing deck means cutting it or routing around. This is one of the reasons to decide where the equipment goes early.
Propane tank placement
Codes set minimum distances from the tank to the house, the pool, the property line, windows, and sources of ignition, including the heater itself. The tank also needs a place the delivery truck can reach with a hose. Buried tanks hide the tank and need excavation and an anode; above-ground tanks are simpler and can be screened with planting or a fence panel. Size the tank for the heater's use over the season so refills are not constant.
Permits and inspections
The gas line has its own permit and its own inspection, pulled by the licensed gas contractor. The pool permit does not include it, and the heater cannot be fired until the gas inspection passes. In Guilford, Forsyth, Davidson and Alamance counties this runs in parallel with the pool inspections when it is scheduled early. The stages of a gunite build shows where it fits.
At the heater
A shutoff valve, a sediment trap, a flexible connector and, on some installations, a regulator sit at the heater. The heater needs clearance around it for air and service and must be vented properly; a gas heater under a low roof or too close to a wall is a carbon monoxide and performance problem. The equipment pad layout accounts for this.
Signs of an undersized supply
Heater lights, runs briefly and shuts down. Heater runs but the pool warms much slower than its rating suggests. Other gas appliances in the house weaken when the heater fires. Any of these means the supply, not the heater, is the first thing to check. Why the pool heater will not fire works through the diagnosis.
We coordinate the gas contractor on every heated pool we build across the Triad, including Winston-Salem and Stokesdale. Book a free consultation and we will look at whether natural gas, propane or a heat pump is the right fit for your yard.