Mobile home heat not working? Electric furnaces and package units, explained

Manufactured homes have their own heating equipment. It is built and listed for manufactured-home use, it connects to ducts that run under the floor instead of through an attic, and it fails in its own particular ways. Many HVAC contractors would rather not work on it. We do. It is a regular part of our work around Apopka, where manufactured homes sit alongside every other kind of house.

Here is what is in your home, what usually goes wrong, and what you can check before calling.

Which system do you have?

An electric furnace in a closet. This is the most common setup. A tall cabinet sits in a hallway closet behind a louvered door and blows warm air down into ducts under the floor. The label usually says Intertherm, Nordyne, Miller or Coleman. If you have central air, the cooling coil sits in or on the same cabinet, with a condenser outside.

A package unit outside. All the heating and cooling is in one box next to the home. It might be a heat pump, or an AC with heat strips built in. It connects to the floor ducts through large flexible ducts that run in under the skirting.

What fails in an electric furnace

An electric furnace is a set of heating elements, the switches that turn them on in stages, and a blower. Most faults are one of these:

• Sequencers. These stage the elements on one at a time. When one fails, the blower runs but you get no heat, or only part of it. This is the most common no-heat repair on these furnaces.
• Elements. Most furnaces have two or three. When one burns out, the heat still works but feels weak, and the house falls behind on cold nights.
• Limit switches. These shut the elements off when the cabinet overheats, which almost always means restricted airflow. Look at the filter and the return before blaming the switch.
• The blower motor or its capacitor. If there is no air at all, this is a likely cause.

The closet door is part of the system

On a closet furnace, the louvered door is the return air path. The furnace pulls air in through it. A coat rack, stored boxes or a solid replacement door starves the furnace of air. It overheats, trips its limit and cycles off. Keep the door louvered and the front of it clear. Check where the filter is: often it is in the door itself or in a rack just inside the cabinet.

Ducts under the floor

Supply ducts run through the belly of the home, wrapped in the underbelly barrier. Two problems come up again and again:

• The crossover duct on a double-wide. A flexible duct under the home connects the two halves. If it gets crushed, disconnected or chewed by animals, one half of the house gets little or no heat.
• The connector on a package unit. The flex ducts from the outdoor unit to the floor get knocked loose or flattened, and the heat goes into the crawl space instead of the house.

The giveaways are one end of the house that is always colder than the other, weak air at the registers, or warm air you can feel blowing out under the skirting.

What you can check yourself

1. 1The thermostat is on Heat and set a few degrees above room temperature.
2. 2The breakers. An electric furnace usually has its own large breaker, and package units have a disconnect outside.
3. 3The filter is clean, and the closet door and return are not blocked.
4. 4With a flashlight through the skirting access panel, look for a duct lying loose on the ground. Do not crawl under. Snakes, wasps and fire ants like it there as much as the ducts do.

What repairs cost

A sequencer or heat relay replacement typically runs $180–$350, and that covers most electric furnace no-heat calls. Element and blower repairs vary by model. Reconnecting or replacing a crossover or connector duct depends on access under the home. The diagnostic is $89 and credited to the repair, and you get a flat price before any work starts.

We cover Apopka and the rest of Greater Orlando. If you are not sure what you have, send us a photo of the furnace or package unit label and we can usually tell you over the phone.