Power Units


Silent Master

MD Central Vacuum Units are designed and assembled in the USA, built from steel, and entirely powder-coat painted to ensure durability. Strategically selected for optimum performance, motors are installed at the base of the unit. This design keeps the vacuum unit cooler, resulting in optimum compaction of debris and less wear and tear on the system. Less wear and tear means less maintenance, which adds up to a longer lasting system.

Specifications: 120 Volt | 240 Volt


SilentMaster S2

SilentMaster S4  

SilentMaster S44

SilentMaster S5

MD Part # S2254ND S2155AD S2155ADxx S2257ND
Complete Details
- Performance
- Features
- Installation

Motor Dual by-pass
5.7", 2-stage
Single by-pass
5.7", 3-stage
Single by-pass
5.7", 2-stage
Dual by-pass
5.7", 3-stage
Max Airwatt* 495 458 653 905
Max Amp 16 13.6 16 27.8
WaterLift 84" 139" 148" 139"
CFM at 2"opening 166 101 130 191
Volt 120 120 120 120
Height / Width 37" / 14" 37" / 14" 37" / 14" 37" / 14"
Weight 43 lbs 42 lbs 42 lbs 49 lbs
Trash Capacity 12 gallons 12 gallons 12 gallons 12 gallons
Max Ft2 6,000 6,000 8,000 20,000
Filtration Type Disposable Bag: 3 Stage HyperFlow¨ or Sealed Microfiltration
Warranty** Six Years + Lifetime, or Write Your Own Warranty
Protection Resettable Minibreaker
Construction 18 & 20 Gauge Steel
Finish Powder-coat Paint and Sealant Inside and Out
Micron Filtration .3 microns (and more than 99% of particles under 1 micron)
Quietness 62dBA 62dBA 68dBA 62dBA
Dual Exhaust
Dual Intake Valves
Utility Valve Connection

* Factors other than air watts should be taken into consideration including: altitude, amount of hours of daily usage, complexity of pipe installation, length of furthest vacuum inlet, noise level desired, type and size of filtration, country of origin, construction materials, and budget. The square footage recommendations on this page are solely based upon the suction capabilities of the unit.

**SilentMaster Warranty
M.D. Manufacturing, Inc. warrants its SilentMaster power units against electrical component failure for a period of six (6) years. Any parts (excluding filters) required within the first six years will be furnished free of charge by the Authorized Dealer from whom the power unit was originally purchased. In addition, all SilentMaster units are guaranteed for life against defects in materials and workmanship. If an Authorized Dealer is not nearby, M.D. Manufacturing, Inc. will honor and perform required warranty services. The end user must return the unit to the factory freight pre-paid. This warranty does not apply to commercial applications, misuse, abuse, acts of God, operating without the filters, or units tampered with by unauthorized personnel.

Write Your Own Warranty
If you, the owner, believe there exists a more thorough or effective warranty by another central vacuum manufacturer, M.D. Manufacturing, Inc. will honor the other company's warranty in lieu of the SilentMaster Warranty under the following conditions: A complete copy of the alternate warranty in writing must be attached to the M.D. Manufacturing, Inc. Warranty Registration Card. This card must be sent postage pre-paid to M.D. Manufacturing, Inc. MD will then honor the commitments listed on the alternate manufacturer's warranty including issues of non-transferability, wear and tear, or other exclusions.