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Need btu rating of Dunham cat. V67755

Need to find out the BTU rating of a Dunham cat. # V67755 unit heater. This is a ceiling mounted steam heater with a fan that blows air across the coil used in a warehouse. 2 PSI steam is supplied to the unit. The fives at the end of the cat. number may be the letter "S" instead, I can not tell for sure. The only other information on the unit is a serial number of 144313 and the mfg.: C. A. Dunham Co.

Is there a source or chart available to find out the rating? The customer is looking at changing these units, 7 total, from steam to hot water heaters. So, if there is pressure drop/flow rate charts out there I would be interested in that information also.

Thanks in advance.


  • Steamhead
    Steamhead Member Posts: 16,719
    Two possibilities

    V775, 186 MBH, or V675, 162 MBH on steam. Hard to tell from your info which one it is, if you measure the height, width and depth it will help. On hot-water at 180 with 20-degree delta-T, V775 goes down to 116 MBH and V675 to 101 MBH.

    That's quite a difference. Add the possibility of freezing if the power goes out for a while, and converting them doesn't look so good.

    If they're complaining of high fuel bills, they likely have bad traps or vents somewhere, or missing insulation, or an inefficient boiler, or any combination of the above. A steam system in good shape approaches the efficiency of hot-water.

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