Owner’s manual
Can you add a downdraft to a cooktop?
Yes. You can add a downdraft blower behind many gas or electric cooktops as long as the cabinet and countertop can be cut to the required opening, ductwork and 120 VAC power can be routed, and the cooktop can be positioned with the correct clearance to the vent. For planning dimensions and clearances, use the 273603 owner's manual.
What has to be true for a retrofit to work
A downdraft add-on is mainly a fit and routing project. For a Broan 273603-STYLE installation, we look for:
- Enough space behind the cooktop for the downdraft housing and lift path
- A countertop cutout that places the cooktop far enough forward so the downdraft fits behind it
- A duct path that can run without hitting joists, plumbing, or wiring (the blower discharge can be reoriented)
- A dedicated 120 VAC electrical supply for the blower system
- Proper alignment so the vent can raise and lower without interference
Key installation specs to plan around (typical for this model)
From the Broan 273603 documentation, the system is designed for a variety of gas or electric cooktops and can be mounted in island, peninsula, or wall locations.
| Item | What to plan for | Why it matters |
|---|---|---|
| Electrical | 120 VAC, 4.0 amps | Ensures safe power and correct motor operation |
| Airflow | 500 CFM | Higher airflow can influence some gas flames |
| Duct size | 3-1/4 in x 10 in | Impacts cabinet space and duct routing |
| Cooktop-to-vent gap | 1/32 in to 1/16 in | Prevents binding when the vent raises/lowers |
Common retrofit issues and the parts that usually fix them
If the downdraft is already installed but does not raise/lower reliably, these parts are frequent suspects:
- Downdraft vent up/down switch S97011238 if the vent does not respond consistently
- Motor gear box 99080590 if the lift mechanism strains, stalls, or chatters
- Range hood wire harness S97010993 if you have intermittent power or a loose connection
Why it matters
Downdraft systems pull smoke and steam down and away at the cooktop, but they require precise cutouts, alignment, and duct routing. Getting the clearances right prevents the vent from rubbing the cooktop and helps the blower perform as designed.
You can order replacement parts for Broan model 273603 from the parts list for this model, or search by model number on Sears PartsDirect.
Last updated: February 2026
What is a downdraft ventilation system?
A downdraft ventilation system pulls smoke, steam, grease, and cooking odors downward at the cooktop surface and exhausts them through ductwork, so you do not need an overhead hood. On the Broan 273603-STYLE downdraft blower setup, the vent rises when activated and the blower speed is adjusted at the vent.
How it works on Broan downdraft systems
Downdraft systems are built to capture airborne contaminants right where they form, then move that air through a blower and out of the kitchen.
Common features you will see:
- A pop-up vent that raises and lowers during use
- A blower that can run at different speeds
- Grease filters that trap grease before air enters the blower
- Duct connections that route air down, left, or right depending on the installation
For model-specific operating and care details, use the owner's manual.
Key specs and installation basics (typical for this design)
From the provided Broan Eclipse downdraft blower documentation, this style of unit is designed for domestic cooking and commonly uses:
| Spec | Typical value shown in the manual excerpt |
|---|---|
| Electrical | 120 VAC, 60 Hz |
| Current draw | 4.0 amps |
| Airflow | 500 CFM |
| Duct size | 3-1/4 in x 10 in (often transitionable to 6 in round) |
Installation planning usually focuses on keeping duct runs short and minimizing elbows and transitions for best performance.
Why it matters
Downdraft ventilation is a practical choice when an overhead hood is not possible (for example, island or peninsula layouts). Capturing smoke and grease at the cooking surface helps keep cabinets, walls, and indoor air cleaner, and it can improve comfort while cooking.
Helpful parts that relate to operation
If the vent will not raise/lower or the controls do not respond, these model-page parts are commonly involved:
For ordering additional Broan 273603 parts beyond the list shown, search by model number on Sears PartsDirect.
Last updated: February 2026
What are the disadvantages of a downdraft system?
Downdraft ventilation on the Broan 273603 can be less effective than an overhead hood because smoke, heat, and grease naturally rise. It also uses cabinet space and requires careful duct planning; the 273603 owner's manual notes high airflow can affect some gas flames and lowering blower speed corrects it.
Common disadvantages of downdraft ventilation
- Reduced capture of rising smoke and heat, especially from front burners.
- Tall pots, griddles, and high-heat searing can let steam and smoke escape before it is pulled down.
- Gas flame disturbance at higher speeds (normal for some cooktops); lowering speed stabilizes the flame.
- More installation constraints than many overhead hoods (countertop cutout, cabinet clearances, alignment).
- Ducting complexity; long runs, elbows, and transitions reduce performance.
- Cabinet space tradeoff; the blower and ductwork take room that could be storage.
What matters most for performance (and why)
Downdraft systems depend heavily on airflow path and layout. The manual emphasizes using 3-1/4 x 10 ductwork (with an option to transition to 6-inch round) and keeping duct runs short with minimal elbows.
| Factor | Typical downside | Best practice |
|---|---|---|
| Duct length and elbows | Weaker smoke and odor capture | Shortest run, fewest elbows |
| Cooktop placement and pot height | Smoke rises past the intake | Use back burners for heavy smoke |
| High blower speed on gas | Flame wavering | Reduce blower speed |
Tips to reduce the downsides
- Turn the blower on before cooking so airflow is established.
- Use back burners for smoky, greasy, or high-heat cooking.
- Keep the vent intake and surrounding trim clean so airflow is not restricted.
- If the vent will not raise or lower smoothly, check the control and lift mechanism; the downdraft vent up/down switch S97011238 is the up/down control used on this model.
Why it matters
With downdraft ventilation, real-world results come from matching the system to your cooking style and installing it with efficient ducting. When those pieces are right, you get better smoke capture and fewer lingering odors.
You can order Broan 273603 replacement parts from the parts list for this model, or search by model number on Sears PartsDirect.
Last updated: February 2026
Do downdraft vents need to be vented outside?
Yes. For the Broan 273603 downdraft ventilation system, any ducted (duct-to-outdoors) installation must vent to the outdoors; this is the required configuration for a ducted fan setup. This removes smoke, steam, grease, and odors from the home instead of recirculating them.
What the Broan 273603 manual requires
Our owner's manual states that ducted fans must always be vented to the outdoors and that you should use only metal ductwork. In practice, that means your duct run needs to terminate outside (not into an attic, crawlspace, or another interior space).
Ducted vs. ductless: what applies to this model
Many downdraft systems are designed primarily for ducted venting; “ductless” (recirculating) operation is only possible when the unit is specifically designed for it and the correct recirculation kit and filters are installed.
Before planning a ductless setup, check:
- Whether your current installation has a connected duct run
- Whether a recirculating kit is specified for Broan 273603
- Whether the correct filters and housings are installed
- Local code requirements for kitchen ventilation and makeup air
- Cooktop clearances around the downdraft intake and switch location
Why the outside-vent requirement matters
Venting outdoors is the most effective way to control indoor air quality during cooking. It reduces grease buildup, moisture, and lingering odors, and it helps keep cabinets and walls cleaner.
Quick comparison
| Setup | Where the air goes | What it’s best at | Typical limitation |
|---|---|---|---|
| Ducted (outdoor vent) | Outside | Best smoke, odor, and moisture removal | Requires exterior duct routing |
| Ductless (recirculating) | Back into kitchen | Helps with some odors | Does not remove heat or moisture |
Parts that can affect vent operation
If the vent will not raise/lower or the blower acts inconsistently, these model-specific parts are common suspects:
- Downdraft vent up/down switch S97011238 (lift activation)
- Motor gear box 99080590 (lift drive mechanism)
- Range hood wire harness S97010993 (power and control connections)
Last updated: February 2026
