Basicly when they turn on your furnace for the first time they should have a magnahelic gauge hooked to the gas valve to see what pressure the valve is operating at, then they should be taking 2 temperature readings one in the supply duct close to the plenum, and the other in the return!!!Originally posted by thompsing
tinknocker can you email me firstname.lastname@example.org not sure about that temp rise, would like to know and hopefully expert will do it right but said nothing about temp rise. Is that temp rise before or after the ductwork mods are done?
these 2 numbers get subtracted from each other and thats your temp rise!!!! every furnace manufacturer posts the reccommended temp rise on the inside jacket of the furnace!!! if the manufacturer recommends a 30-60 degree temp rise and your ends up being 80 then they need to either speed up the blower or change the gas pressure if its to high!!! this will bring it down!!! of course it its to low you need to do the opposite!!!
you should do this anytime your furnace is given a check up, or anytime the duct work is changed!!!