Major Heating & Cooling AIRFLOW & SIZING Problems...
Originally Posted by FredHVAC
The answers above are good...
I know this is an older thread, however, it wasn't completely answered & there will be a lot of Oil heating situations that will have similar problems!
It is October 25, 2012 & the OIL Heating season is beginning...
Due to severe carpal tunnel in both hands; I can't do enough typing to provide all the details regarding what needs to be done to correct both heating & cooling AIRFLOW & SIZING Problems. (Several Extra large RA Filter areas are very important for Mid to larger equipment.)
First, were I in your shoes, I'd have a Home Energy Efficiency Audit performed; then a room by room heat-gain heat-loss calc done.
IMO, the heating & cooling appear to be way oversized which is creating needless problems.
The Thermo-Pride OL6 Low Boy upflow has a LISTED BTUH OUTPUT ranging from +60,000 to +89,000-Btuh depending on which of 3 nozzle flow-rates is selected, either the 0.50, 0.60, or 0.75 GPH rate.
A 0.50 GPH rate, #2 diesel fuel at 140,000-Btuh a gallon * .50 is 70,000 Input *.865 efficiency is 60,550-Btuh Output.
Well, 140,000-Btuh a gallon using the .75 nozzle is 105,000 Input * .865 efficiency is 90,825-Btuh Output. Here in SW WI I heat my farm home with 56,000-Btuh; it has plenty of reserve left-over.
It uses a direct-drive 5-spd blower which at 0.50" static will get the proper heating temp-rise & tonnage airflow increments from 1.5 to 4-ton of cooling.
That OL6 furnace only weighs 250 lbs & the height of the casing is only 34&3/4 inches; considerably lower than most Thermo Pride Low-boys which will provide more room for more than 6-inches of transition between the E-coil & the top of the Oil furnace - reducing back-pressure toward trying to get to an efficient 0.5" of ESP.
If you live in the northern half of the U.S. & into many southern areas of Canada this furnace should cover the majority of those heating & cooling conditions; of course there are heating exceptions.
Tell us more about where you live & how energy efficient you think your home is; that is something you need to pretty accurately know.