EL296 Proper Operation
We recently moved into our new build home that is equipped with this furnace (EL296UH110XV60C-04). From my research and from reading the manual the furnace has essentially 3 speeds (I'm not using it for A/C, only heat). Two speeds for heat depending on demand or time, and one speed for fan only, each of which can be modified slightly on the control board. Since my wonderful builder only installed a single stage stat the furnace is left to it's own devices on when to kick into the high mode. Without the fan turned on this is exactly what happens, the low stage starts and if it can't keep up the high stage kicks in and everyone is happy. The problem I'm having is when the fan is selected to on. When the fan is in continuous operation and there is a call for heat, rather than start with the low stage it immediately ramps up to the high stage for about 1 minute then returns to the low stage for the set amount of time and will kick back into high stage again if required. I find this rush of air fairly annoying and want to know if this is normal operation for this furnace or is something off? I've talked to two local lennox dealers and received different answers from both so I'm hoping I can get to the truth here!
Thanks very much in advance for your help, I'm glad I stumbled across this site!
If it's a cheap builder grade unit, then it's a multispeed blower motor, but the speed are fixed, so the speed required for heating or cooling airflow gets selected. More MFG's only make a 1/3, 1/2 and 3/4 or 1 HP blower motor, but might have 6 difference furnace capacities and 5-7 different AC sizes. Eliminating a few extremes that don't match well, that's about 25-30 combinations of AC size and furnace sizes.
On a few brands/models yo ucan select the blwoer speed at the controller or thermostat. But not likely on a builder grade unit.
What I think your noticing, is that the furance initially fires on high stage to warm the heat exchanger, then ramps down to low stage. Most all 2 stage furnaces do this. It heats it up quicker and prevents condensation forming in the primary heat exchanger. Many furnaces will shut off the blower when they initally ignite the furnace.
I'm not sure there's much you can do. If the ductwork was sized well (not just the minimum to me the contract) the system would be quiet even on high stage. Its also likely that the furnace is oversized and you might have a single stage thermostat and the furnace is upstaging based only on a timer. This is a pathetic way to save $$ on a installation... but common in new construction. Comfort isn't a high priority for home buyers. It's assumed, not demanded.
If you had a midrange furnace with a vairale speed fan or even better a modulating furnace, the continous fan would be low speed, it would stay on low speed even while the furnace initially went to high stage to warm the heat exchanger.
Sounds like your in a cold climate. a modulating furnace would have ben a worhtwhile upgade, but not always easy to do on a home build contract, expecially if a tract home.