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Intertherm Mac1378

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spicymchaggus1
spicymchaggus1 Member Posts: 3
in A-C, Heat Pumps & Refrigeration

I'm trying to find information about my furnace this is All I've found so far it's an international oil burner co mac 1378 and the serial number is n1378mac8jy8-02 I'm trying to find the manual and year of the furnace so I can figure out why it's not lighting any help would be appreciated

IMG_20241223_214332.jpg IMG_20241223_214159.jpg IMG_20241223_214152.jpg

Comments

  • Big Ed_4
    Big Ed_4 Member Posts: 3,409

    Is the pilot lit ? Is there power ? Does the fan run ?

    There was an error rendering this rich post.

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 11,748
    edited December 2024

    This is a very old furnace for manufactured housing or mobile home. It is time to get a new one unless this one has been taken care of with kid gloves.

    that said, as long as the heat exchanger is not breached or cracked, you can still operate it. The first step is to get the pilot lit. There are lighting instructions in the blower compartment.

    First you need to have Gas.. is the gas meter turned on? or if it is Propane, Does the tank have gas in it?

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    spicymchaggus1
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 11,748

    If you have Gas then lighting the pilot according the the instructions will include:

    Screenshot 2024-12-24 at 8.31.37 PM.png
    1. Make sure the manual gas valve is open (A)
    2. Turn the Gas Control Valve beige knob (B) to the PILOT position
    3. Press IN the Gas Control Valve beige knob (B) to start the gas to the pilot burner.
    4. With the Gas Control Knob pressed in, press the red sparker button (C) several times until the pilot gas lights.
    5. Look thru the view port opening (D) to see the pilot flame.
    6. Continue to hold beige knob pressed in for 60 seconds so the thermocouple can heat up and engage the pilot burner.
    7. Release the beige knob after 60 seconds, and see if the pilot stays lit by observing it thru the view port (D).
    8. If the pilot extinguishes, then you need to call for service.
    9. If the pilot light stays lit, then turn the gas control knob (B) from the PILOT position to the ON position.
    10. Turn on the electric power to the furnace
    11. Set the thermostat

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    spicymchaggus1
  • spicymchaggus1
    spicymchaggus1 Member Posts: 3

    Yes the gas is on I've let it run for five minutes turn the thermostat down and tried lighting it and nothing really happens other than the place smells like gas I want to open it up and see if there's corrosion on the ignitor and check the burners but I don't see how and I can't afford a new one

  • Big Ed_4
    Big Ed_4 Member Posts: 3,409

    Is the pilot lit ?

    There was an error rendering this rich post.

  • spicymchaggus1
    spicymchaggus1 Member Posts: 3

    No I can't get the pilot to light but the fan runs and everything has power

  • Dennis
    Dennis Member Posts: 124

    Bad piezo ignitor, bad thermocouple, plugged pilot orifice, corroded, blocked pilot gas tube, bad gas valve. It could be one or all of these issues. I'd start with the ignitor. Open the little door in the round plate above the burner. Push the ignitor a few times, if you don't see a spark it's the ignitor. If it sparks but does not light it could be the pilot orifice is blocked, or the pilot tube is blocked or broken. If the pilot lights and goes out after holding in the pilot button on the gas valve for at least a minute, it's probably the thermocouple, but could be the gas valve. Go with the thermocouple because you probably don't have the tools to measure its electrical output. Gas valves rarely go bad on ancient heaters like your's.

    It appears there are two thermocouple one on the pilot valve and one on the main gas valve. I believe you might need to light the pilot valve while holding in the button to the right of the white button on the gas valve. The white knob on the gas valve does not appear to have a pilot position.

    There was an error rendering this rich post.

    spicymchaggus1
  • cloff
    cloff Member Posts: 1

    on an intertherm 1378 Furance do you have a better photograph and wiring

    Schematic of the boars where the fan plugs into and the off switch is located.

    The box is located just above the gas valve and on the top of the box panel

    There are two plug ins the regulated fan plug in on the left then the summer fan plug in then on the far right and on and off switch.
    Inside the box there are several wires that connect to the plug ins as well as a panel that has the two heat sensor to regulate the temperature near the heat exchange that has three screws holding it in place.

    I am trying to find a better photograph of the wiring on this panel.

    The box I am talking about is in the second photo found in your intertherm mac 1378 display

  • rick in Alaska
    rick in Alaska Member Posts: 1,522

    I would seriously look at this furnace to make sure it is not cracked or the firebox hasn't collapsed. That is a very old furnace, and could have used up its life, especially if it hasn't had maintenance done regularly.

    Rick

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