OEM Carrier 40VA Control Transformer for PY3GNAA36090AA Furnace

The control transformer steps your home's 120/240-volt line voltage down to the 24-volt low-voltage signal that powers the thermostat, gas valve, control board relays, and inducer circuit throughout your Carrier system. When it fails, nothing on the low-voltage side responds: the thermostat screen goes dark, the furnace won't fire, the blower stays silent, and the air conditioner won't engage even though the breaker is on. A failing transformer may also hum loudly, give off a burnt-varnish smell, or trip its internal protection intermittently — making the system work one moment and die the next. This is a 40VA, 24-volt secondary control transformer with a primary tapped for 120/208/240 VAC, delivering roughly 1.67 amps — enough to drive the ignition control board, inducer relay, and gas valve simultaneously. OEM units use a correctly sized magnetic core and Class B insulation rated to absorb the inrush of the gas valve and contactor coils without overheating. Transformers look interchangeable, but an undersized aftermarket unit (often only 20-25VA) sags under load, dropping voltage below the 18V threshold the gas valve needs to stay open. That causes nuisance lockouts and short-cycling that are nearly impossible to diagnose. The OEM VA rating and tap configuration guarantee stable 24V under full system load. Install difficulty: 2/5. Tools needed: 1/4" and 5/16" nut driver, multimeter, wire strippers. Label every lead before disconnecting it. #1 safety warning: KILL THE BREAKER first — the primary side carries full line voltage that can shock or kill you even with the thermostat off. Ships same business day from our stocked warehouse on orders placed before 3 PM CST. Backed by a 1-year OEM warranty and 30-day hassle-free returns on uninstalled parts.

Compatibility

This part is compatible with Carrier model PY3GNAA36090AA. Always verify the part number against your unit's data plate before ordering.

Why Choose OEM?

OEM parts are manufactured to the exact factory specifications for your unit. Generic aftermarket alternatives may fit physically but often use lower-rated components that reduce equipment life and void manufacturer warranties. When the cost difference between OEM and generic is $10-30, the OEM part is always the smarter investment on a system worth $5,000-$15,000.

Shipping & Returns

Same-day shipping on orders before 3 PM CST. Standard delivery 2-5 business days, express options available at checkout. 30-day hassle-free returns on uninstalled parts — free return shipping included. 1-year OEM factory warranty coverage.