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Melted Coil drain pan

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Robert_H
Robert_H Member Posts: 330
in THE MAIN WALL
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An AC problem but I think the cause is on the furnace side…

I Went to a "furnace leaking water" call today and it turned out to be a melted condensate drain pan under the coil. First one for me. The new pan won't be here for a week. The person is on oxygen and the sense I get probably end of life scenario. So we couldn't leave it. After getting the drain pan out I patched it up with angled aluminum, flex tape and got drainage to the condensate pump.

The reason I'm actually posting this is because I'm in the "why did this happen" mode and need to get this figured out before winter time rolls around again and the heat comes on. The owner tells me that this happened last summer as well but it wasn't as bad. The rust I see around the base of the Furnace tells me there was a pretty good bit of water around here last year.

I'm thinking there is a control issue where the temperature in the bonnet is being allowed to get too high or was allowed to get too high at some point. This (the high heat) might have possibly even been repaired before we got involved. I serviced this boiler in February and didn't see any issues with it getting too hot (net break temp 410) and had good combustion numbers and nothing to indicate a breach in the heat exchanger.

the furnace is an NOMF155E19, and the coil is an AllStyle ASUC48-M2866G-7-VP4

Comments

  • 109A_5
    109A_5 Member Posts: 4,213

    Restricted air flow (plugged filter or evaporator or other air flow restriction) and an inoperative high limit switch.

    image.png
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 20,507

    Undersized ductwork either supply or return.

    Supply registers closed off.

    Supply or returns blocked by furniture or carpeting

  • mattmia2
    mattmia2 Member Posts: 17,500

    some coil/furnace combinations are supposed to be installed with a spacer between the furnace and coil, especially oil furnaces, check the instructions.

    HVACNUT
  • HVACNUT
    HVACNUT Member Posts: 7,531

    An evaporator coil cannot sit directly on top of an oil fired furnace. It needs a minimum four inch spacer.

    If it does have the spacer, check the furnace ratings for heat rise and max supply air temperature, then start testing. Also make sure its the correct firing by checking the nozzle and pump pressure.

  • GW
    GW Member Posts: 5,193

    did you do the basic temp rise? Running wayyy too hot. The monkey will jump on your back if you put in a new pan and it happens again. Gotta get more air or less heat. Is the heat exchanger buggered?

    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    gary@wilsonph.com
  • pecmsg
    pecmsg Member Posts: 7,290

    150K BTU Oil Furnace?

    What's the temperature Rise? What's the static pressure TESP?

    Yes, there should be a 4-6" riser between the furnace and a/c coil!

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