furnaceheating
I am trying to replace my 33 year old furnace. The brand is Carrier and model is 395BAW048095.
I couldn't figure out the correct vent type and configuration (down-flow, multi-position, up-flow).
I wonder if someone can give some guidance and offer some suggestions for good furnace brand/model that can replace this one. Thanks!
Check the high limit switch. If the furnace is allowed to continuously over heat, It's likely the high limit switch has burned out.
Make sure that the outlet vents are clean, and clear of debris. You need good air flow both in, and out of the system. also make sure the heat exchanger is clean, so it can transfer heat properly to the passing air.
If the thermostat has an option for Fan, switch it to Fan and make sure the fan starts. If the fan does not turn on, you should contact a trained HVAC tech. Capacitors can be deadly if not handled properly. You could accidentally discharge the capacitor into yourself, leading to electrocution. Or short the capacitor, leading to an exploding capacitor. In either case, it could be deadly.
Somewhere inside the service panel of the furnace, there should be a schematic for the furnace. This may list the electrical specifications of the blower motor. If not, the blower motor itself will have a label on it. It should list the voltage, amperage, horsepower, etc.
An ammeter is used to measure the amount of current flowing through an electrical circuit. You can use a clamp on ammeter to measure the amount of current being used by the blower motor while it's running.
Simply set the meter to measure current (A in the pictured meter), and clamp it on the hot wire feeding the motor.
This method may require working on or near live wires, please use caution and/or consult an expert to take the readings
With the above information and Ohm's law, it's easy to determine how much power the motor will use over a given time period.
Ohm's law says that Power (P) = Voltage (V) x Current (I), so we can determine how much power the motor uses at a single instant in time.
ex.
P = 115V * 5.2A
P = 598 Watts
Next we have to determine how many kilowatt hours the motor will use, which we do by dividing by 1000.
P = 598 W / 1000
P = 0.598 kWh
So for every hour the motor runs, it will use 0.943 kilowatts of power.
Total power/day = 0.598kWh * 24h
Total power/day = 14.352kWh
Total power/month = 14.352Kwh * 30
Total power/month = 430.56kWh
Finally, if you multiply this number by the amount you pay per kilowatt hour. You'll see just about how much it costs to run the motor constantly.
Cost = 430.56kWh * $0.07
Cost = $30.14 per month
Notes:
Results using this process will be an estimate only.
Values used are not actual values, they are example values only.
Calculations may be incorrect, nobody checked my math.
Best Answer
You know which way your filter is installed, right? You'd need to in order to change it. That tells you flow direction. So does the air come out of your furnace at the top or bottom?
Most are upflow, and I suspect the same here. The lower panel covers the fan and fan motor, which drives air up through the heat exchanger and out the top. Sound right?
Be aware that modern furnaces tend to be more complex than those from the era you're replacing, and as such can require more knowledge to set up and tune for your duct system. Also, most are going to be direct-vent types that need different exhaust venting than what you have now. You may want to employ an HVAC technician for this project.