HVAC Blower will not turn off

Could be a bad blower motor resistor,mounted by the blower.

There is a little motor on the heater box under the dash that needs to be replaced. It's called a blend door actuator...

If the blower fan in the furnace won't turn off, there is a tripped/blown limit. It's a safety. As for your condenser fan it could be a run cap or motor. Do yourself a favor and have a licensed HVAC contractor take a look. Find a NATE certified or ACCA member. You will find a much better more qualified contractor.

Hello, usually this is a sign of a bad blower relay on the intergrated control board. The only option is to replace the control board.

On the call for heat from the thermostat the inducer should come on first, a pressure switch proves that the inducer is moving enough air up the stack, closes and energizes the ignition and burners come on. 30 to 60 seconds later the blower comes on. Everything should stay on as long as the thermostat is still calling for heat. When the thermostat is satisfied the burner and inducer shut off and the fan will run to remove the heat from the heat exchanger and then shut off. Cycle complete. Some inducers have a post purge so when the thermostat is satisfied the burner shuts off, the inducer runs for 30 seconds or so and then shuts off. I am thinking that your furnace may be running on the limit switch and when the burner is off but the inducer stays on, maybe the limit is shutting of the inducer. Check your air filter and make sure all your heat registers are open and that the return air grill is not blocked.

You are correct. If the inducer motor is warm, but not running, it has seized up. If you replace this yourself, I also suggest that when you replace the inducer fan, check to make sure the secondary heat exchanger isn't clogged, or the condensate drain(s). If you have an HVAC contractor replace it, he should do this for you. It shouldn't run more than $350, to have it replaced and he can check for clogs (The price I'm quoting is for standard hours).

You can check this yourself by running the inducer fan without it being attached to the furnace, then attaching it to the furnace. If you notice a significant reduction in airflow, then you have a clogged secondary heat exchanger. I've run across this situation before on this particular model. The owner recenly replaced the inducer motor, but couldn't figure out why he was still having problems. I suspect the clogged heat exchanger contributed to the inducer motor to failing previously, and feel It would definitely be worth checking while you have the fan removed to help eliminate any future problems that could result from this, including heat exchanger failure. The manufacturer of this unit actually recommends you clean the secondary heat exchanger every year, but this is overkill if your furnace was installed and set up properly. I'd recommend doing it every 10 years and you're at that mark now. Instructions on how to do this are in the manual for this unit if you have it. Otherwise, e-mail me at [email protected] and I can send you a copy.

Finally, check the limit and flame roll out switches after replacing, as they could have tripped when the motor failed.

On a call for heat, the 24 volt thermostat sends a signal to the control module. The control module will indicate a call for heat with a light on the control either blinking or remain solid depending upon model. The inducer (exhaust) blower will purge all gasses from the furnace and pressurize a pressure switch. Once the pressure switch tells the module to continue, the electronic ignition will energize and send 120 volts to the igniter. The igniter will glow and you will be able to see it if viewed thru the small inspection port. Once the igniter gets hot enough, it sends a signal to the module opening up the gas valve (24 volts). Either a pilot will come on or the burner tube will ignite then spread the flame to all burners. Lastly a safety sensor will be looking for a certain temperature within a few seconds and the furnace will continue to operate and the room air blower will turn on in a minute or two.

What could go wrong? The unit will not run if there is no signal from the thermostat (bad thermostat or broken wire), the control module does not sense a signal from the thermostat (bad control), the inducer does not energize (bad motor), the pressure switch does not close (blocked vent piping, bad switch, plugged condensate hose), the igniter does not energize (bad control, bad igniter), the gas valve does not open or there is no gas (bad gas valve, broken wire, no gas), the pilot does not light (dirty pilot), the burner does not light (bad burner, plugged orifice, not enough combustion air), the flame does not spread to each burner (bad flame spreader, dirty flame spreader, more bad burners), the flame safety sensor does not detect flame (dirty or bad flame spreader, bad flame sensor, broken wire, bad control), or the room air blower does not energize (bad fan motor, bad control).

Sound like your indoor blower motor is bad.

The SHR2005R will turn on the furnace Blower if the furnace is not running to circulate the fresh air. The reason the furnace will not trun on the HRV is, the purpose of the HRV is continuous Ventilation in your home. It should not be turned off when your furnace is not running. That why Fantech has not design the HRV's to run that way. I hope this helps.

bad board . replace it .