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Williamson 5 in 1 anyone know the model number of the outdoor units

Any 1980's guys out there that know the model number on a Williamson 5 in 1?

My utility has a small kicker when we are downsizing. The name plate vanished years ago. Old system was a 30 amp and new system is a 20 amp, so my grand assumption is the we are smaller, hence the incentive through mass save
Gary Wilson
Wilson Services, Inc
Northampton, MA
[email protected]


  • Steve MinnichSteve Minnich Member Posts: 2,143
    edited May 2018
    I don't but I wish I did. I just did a search on the 5 in 1 and there's very little information out there. I was looking for PDF files specifically but no luck.

    This is the furnace I wanted when I started out but was living in an apartment at the time. I'm happy to say that I installed at least a couple of those.
    Steve Minnich
  • GBartGBart Member Posts: 677
    I don't know but you jogged my memory, worked on one once with a line set that had a plastic suction line., those old pre charged line sets.
  • newagedawnnewagedawn Member Posts: 549
    good luck, they just completely fell off the planet, nothing, nowhere, what size supply duct? that could give you a cfm to run some numbers
    "The bitter taste of a poor install lasts far longer than the JOY of the lowest price"
  • John Mills_5John Mills_5 Member Posts: 870
    Outdoor unit would be 7420-xx-xxxx. The 2 digits in the middle tell the size. 25 is 2.5 ton, 03 is 3 ton for example.
  • GWGW Member Posts: 3,223
    Thanks all, turns out the homeowner had the name plate filed away in the house. Who woulda thunk
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • John Mills_5John Mills_5 Member Posts: 870
    7320, that's a heat pump
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