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Underszed gas supply

Gchurchi Member Posts: 2
Hi, the input 103 mbtu and the supply line to the boiler is about 32' and 1/2" ID copper tubing which is not capable of suppling that many mbtu's (so I am told) my question would be am I using more gas than I should be? pressure seems OK no lockouts etc's Propane is the choice of gas.



  • lchmb
    lchmb Member Posts: 2,997

    I would have to get my charts from my truck but if you have 1/2 id (5/8 od) you should be good for around 107k btu...if memory serves me right...Has a flow and lock up been done to the unit?
  • icesailor
    icesailor Member Posts: 7,265
    Gas Supply:

    5/8" OD soft copper may be on the line but 1/2" screw pipe is higher and better.

    A HTP Munchkin 80M (80,000 BTU) has a 1/2" inlet but HTP REQUIRES a 3/4"as line, full size from the source to the boiler for proper operation. Does the installation manual say that 1/2" ID/ 5/8" OD copper tube is OK for feeding this appliance? Regardless what the installer says that it is OK. The manufacturers instructions always take precedence. 
  • Tim McElwain
    Tim McElwain Member Posts: 4,480
    Semi Rigid Copper Tubing K or L

    1/2" outside is .625 inside is .527 and 30 feet at 11" W.C. pressure with an allowable loss of 0.5" W.C. will give you 104,000 BTUS.

    1/2" Schedule 40 black pipe 30 feet at 11" W.C. with .5" W.C. allowable pressure drop will give you 160,000 BTU's
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