Arkansas HVACR NewsMagazine January 2024

HVACR NewsMagazine January 2024

Tech News

It’s also worth noting that improperly sized flue piping might not allow the inducer fan to create enough pressure to close the switch. Make sure you size the exhaust to the manufacturer’s vent tables.

come in handy here, especially if you notice a rotten egg smell or water leak. Water can be pretty destructive, and it’s a big indicator that something is amiss. Again, we don’t want to see water leaking from the heat exchanger, but water leaks can also cause equipment to fail, especially if it leaks onto the circuit board . Secondary Heat Exchanger The secondary exchanger consists of a tube and fins, like the evaporator of an A/C system or heat pump. Similar to an evaporator, those fins can collect debris, and heat transfer becomes more difficult, which doesn’t allow for good airflow over the heat exchanger. Internally, a clogged secondary heat exchanger doesn’t allow the flame to be drawn through its passageways, and that can lead to flame rollout. Externally, secondary heat exchangers can get dirty without regular filter changes and blower cleanings, so regular maintenance is a must. Preventing Animal Nests from Getting Into the Flue It’s an age - old problem: bird’s nests, squirrels, or even raccoons in the flue. A common “solution” is to put a screen over the outdoor exhaust piping, but water vapor can condense and freeze over that screen in cold weather. However, flush mount kits and concentric piping that draw air from the back side of the vent kit may help. A flush mount wall termination kit is an oblong-shaped fitting where both of the pipes are terminated through the wall next to each other. There is a hole in the face of the fitting that allows the exhaust to blow away from the home. The rest of the fitting has rounded edges and draws the air in from the backside

Source: Goodman

Ignition Sequence

Once the pressure switch closes, the board checks all safety circuits to make sure they’re closed before beginning the ignition sequence. (Remember: the rollout switch is a manual reset switch.) Combustion requires there to be a proper draft (confirmed by the pressure switch), heat (from the igniter), and fuel (from the gas valve). The igniter and gas valve will start the flame, which will be proven via a flame rod. Once the flame is proven, the blower can start moving heat throughout the home via the ductwork.

Thinking Through the Troubleshooting Process

Ty’s troubleshooting process starts by looking for the obvious: loose wires, water buildup, debris in the burner compartment, obstructed exhaust and intake venting, and a lack of natural gas (such as if the customer didn’t pay the gas bill). Your senses of sight and smell