High-efficiency overhead dehumidifier for controlled-environment agriculture, greenhouses, and warehouses. Removes up to 225 pints/day and is commonly ceiling-hung to save floor space. (Legacy model; see “If Buying New” below.) Greenhouse Megastore
AT A GLANCE (LEGACY “DUAL 225” MODEL)
• Capacity: 225 PPD @ 80°F / 60% RH
• Voltage: 208–240 V (dedicated circuit recommended)
• Max current draw: ≈ 6.9 A
• Airflow: ~526 CFM (typical)
• Operating range: ~56–95°F
• Filter: MERV-11 (commonly 16″ × 20″ × 2″)
• Mounting: overhead or floor; ductable; continuous drain capable
• Typical weight: ~150–160 lb
• Example dimensions: ~38″ W × 22″ H × 20″ D (varies by revision)
• Warranty on many units: up to 5 years (check your serial)
Sources: product listings & manuals. AMG Air
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IMPORTANT: IF BUYING NEW
Quest lists the legacy Dual 225 as discontinued and points buyers to the updated Quest 225 (208/230 V) with higher efficiency. Headline specs:
• Capacity: 225 PPD @ 80°F / 60% RH
• Efficiency: up to 7.6 pints/kWh
• Current draw: ~5.5 A @ 230 V (6.1 A @ 208 V)
• Power: ~1230 W
This newer 225 is the current production path. Quest Climate
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WHAT IT’S GOOD FOR
• Holding target RH in flower/veg rooms, drying rooms, and propagation areas
• Reducing disease pressure (botrytis/powdery mildew) via tighter VPD control
• Freeing floor space (overhead mount) and allowing ducted, zoned dehumidification
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BASIC SIZING (PRACTICAL START)
- Count moisture sources: plant transpiration, irrigation, wet floors, humid outside air.
- Add a safety margin (10–20%) for peak transpiration and door-open events.
- For multi-room sites, split capacity across rooms for redundancy.
Tip: Quest provides a Sizing & Selection guide/calculator on the product page—use it to confirm your math. Quest Climate
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INSTALLATION QUICK GUIDE
• Mounting: Overhead with rated hardware (unistrut/eye-bolts) or floor-mount per manual. Ensure structural support for ~160 lb unit. AMG Air
• Electrical: 208–240 V dedicated circuit (GFCI where required). Follow nameplate amps and local code; many installs use a 15 A breaker on the newer 225. Low-voltage terminals are available for external humidistats. Quest Climate
• Control: Onboard digital control on newer units; legacy units often use a remote hygrostat (24 VAC). Keep the sensor away from supply vents/doors for accurate readings. Quest Climate
• Drainage: Continuous gravity drain to a trapped line; optional condensate pump if needed. Keep runs short with proper slope. Greenhouse Megastore
• Ducting (optional): Supply/return collars allow intake from the humid zone and discharge to conditioned space; balance airflow to avoid short-cycling. (See model manual.)
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ROUTINE MAINTENANCE
• Filter: Inspect monthly; replace MERV-11 (typ.) every 1–3 months depending on dust/pollen. AMG Air
• Coils: Vacuum fins and blow out dust; keep intake clear for rated CFM.
• Drain: Flush line and check trap; test condensate pump if installed.
• Controls: Verify setpoints; recalibrate/relocate hygrostat if readings drift. Quest Climate
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TROUBLESHOOTING QUICK LIST
• Unit runs, RH won’t drop → undersized capacity, doors open, or poor airflow; verify CFM/path and seal room.
• Icing/short cycling → room too cool, restricted airflow, dirty filter/coil; verify operating range (~56–95°F). AMG Air
• Water not draining → clogged trap or no slope; clear/prime trap; test pump.
• Control issues → miswired external hygrostat (keep 24 VAC control wiring isolated from high voltage). Quest Climate
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ACCESSORIES & OPTIONS
• Remote humidistat / building automation connection (low-voltage terminals) Quest Climate
• Duct kits (supply/return) for remote intake/discharge
• Hanging kits / vibration isolators
• Condensate pump kit for long drain runs Greenhouse Megastore
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COMPARE: LEGACY DUAL 225 VS NEW QUEST 225 (208/230 V)
• Status: Legacy model discontinued → New 225 is current. Quest Climate
• Efficiency: Legacy listings ~6.1 pints/kWh vs new up to 7.6 pints/kWh. Greenhouse Megastore
• Amps: Legacy around 6.9 A vs new ~5.5–6.1 A (same PPD). AMG Air
• Controls: Newer units add digital control with external control option. Quest Climate
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FAQS
Is 120 V available?
No—this class is typically 208–240 V. Check your panel capacity and breaker size before purchase. Quest Climate
How many units do I need?
Start with total moisture load and use the Quest sizing guide; many growers deploy multiple smaller units for redundancy and better distribution. Quest Climate
Can I hang it overhead in a small room?
Yes—this model is designed for overhead install; confirm structure supports the weight and follow clearances in the manual. AMG Air
What’s the filter spec?
Legacy Dual 225 listings commonly show MERV-11. Newer 225 documentation may vary by revision; check your serial/manual for the exact size/MERV. AMG Air
Where do I get the manual?
Quest’s site lists the new 225 (208/230 V) specs and downloads; legacy Dual 225 manuals are still available via archived PDFs. Quest Climate
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DISCLAIMER
Specifications can vary by production run. Always verify nameplate ratings, the installation manual, and local electrical/mechanical codes before purchase and install. © [Current Year] Quest Dual 225 Guide.