I am working my way through a Manual J load calculation for an older home (built in 1965) I just acquired in preparation for assessing HVAC upgrade options. I am using MJ8 v2.50 and the ACCA MJ8ae speed sheet. I think I have been able to figure most of the inputs out from the manual, but one thing that has me stumped is how to select the correct soil condition type for Table 4A Construction Number 22 Slab on Grade F-value. I have no slab insulation so the difference between Light Dry Soil and Heavy Moist Soil is over 2000 Btuh. My estimated total heading load is 45K Btuh so slab loss not a huge factor, but I would like to get it right if possible.
I have not been able to find any guidance in Manual J or searching the web on how to determine the soil condition. The USDA NRCS soil map says the soil is "Sandy Loam with 0-5% slopes" which sounds like Light Dry to me. Can anyone confirm this or point me to an appropriate reference? Thanks.
I have not been able to find any guidance in Manual J or searching the web on how to determine the soil condition. The USDA NRCS soil map says the soil is "Sandy Loam with 0-5% slopes" which sounds like Light Dry to me. Can anyone confirm this or point me to an appropriate reference? Thanks.
source https://hvac-talk.com/vbb/threads/2243009-Manual-J-question-Soil-condition-code?goto=newpost
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