Question #2. What specifically needs to be done?I understand the concept of "more air" or get the static pressure to 0.5" WC, but I want to know specifically what the HVAC professional needs to do to achieve this, e.g. enlarge cut if for a 20" x 25" filter, add another cut in for two filters (perhaps by wrapping the return duct around the furnace so I can have a filter on the side AND the back, enlarge the main return trunk, replace the high-limit switch, etc.
We can only guess from here. Since we don't can't see and test things for ourselves. Your HVAC pro is the one that can tell you what needs done.
Well, didn't see any disagreement with me.
Originally Posted by Rewind
The newer engineering in size & minor modification allow them to handle somewhat higher static before they begin to unload.
The blower design curves should be in every mfg'ers' manual. I emailed a Thermo Pride Engineer to get a copy of the Oil furnace blower curve in question.The Thermo Pride belt drive blower wheel is large enough to handle 1.5 to 4-Ton of cooling, they just use bigger motors, wheel ratios & increased wheel RPM.
Both you & beenthere are correct in that the wheels, & especially the motors, still won't handle too high a static.
The backward curved blades are designed to handle higher statics.
Come-On; You & beenthere need to get together shake hands & have a beer.
Last edited by udarrell; 02-13-2011 at 06:48 PM.
Reason: A Wordage change...
Using a higher static blower only increases noise and turbulence.
Still no substitute for a properly designed and installed duct system. Treat the problem, not the symptom.
A good HVAC tech knows how, an educated HVAC tech knows why!
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.
is the evap coil clean could have some buildup on after 10 years.