This troubleshooting situation has a history. In the six years that the up-flow gas furnace in this three bedroom house has been in service, several attempts have been made to solve the problem of one bedroom that, according to the customer, is always too cool during the heating season. This residence is a brick home on a slab, and the air handling system, which located in the crawl space above the ceiling, is shown in Figure One.
In this troubleshooting situation, the equipment that needs servicing is a condensing gas furnace in a relatively small home of approximately 1,200 square feet. The capacity of the unit is 40,000 Btu and it is equipped with an LED readout system.
Bob and Tim were at a customer’s house doing a seasonal checkup on a condensing gas furnace. This was routine service carried out every year on this customer’s equipment per a service agreement. But when they tried to operate the furnace, the burner would not light.
In this month’s troubleshooting situation, you’re responding to a customer’s complaint that his furnace isn’t heating properly. The equipment is an 80 percent AFUE, natural gas, induced draft unit that employs a hot surface ignition system.
It was the first really cold day of the winter and Bob and Tim were on the way to a service call on an oil burner. The customer said that they had no heat. It was about 15°F outside so they were in a rush to get there.
Blower motor breakdown can be the result of anything from old age to failed bearings, high amp draw, electrical failure in the windings, dirt accumulation, and more. Knowing how to troubleshoot and diagnose problems with these motors is an essential skill an HVAC technician must possess.
Bob and Tim were on their way to a no heat call for a gas furnace. Tim asked, “What do you think we need to look out for on this call?” Bob said, “It could be any number of things. We will start by talking to the homeowner and see what she knows.”
Your troubleshooting situation involves a standard natural gas, induced draft, hot surface ignition system furnace. This is a new installation that has been accomplished in anticipation of the upcoming heating season, and the problem is that during the initial start-up the unit did not perform properly.