The Whalen 50/50 system features all the advantages of a conventional 4-pipe system but reduces pump and piping requirements by 50 percent. During design day conditions, two pumps---each sized to carry 50 percent of the total flow---operate in parallel delivering 100 percent of the hot or chilled water required. Marginal days can be handled either by one or two pumps circulating hot or chilled water through one or both heat-exchangers. This design allows pump and motor usage to be staged as conditions require, keeping energy demands at a minimum.

• Elimination of all electric valves, dampers, and flow control valves
• Absence of any soldered connections within the cabinet
• Reduction in operating costs with two fans per unit sized for 50 percent of total CFM required
• Simplified maintenance procedures which reduce costs
• Significant reduction of total installation and operating costs
How It Works
Outdoor Air - 20°F and Below
Pump P1 and P2 are operating in parallel. P3 is on standby and remains off.

Outdoor Air - 20°F and Below 40°F
System moves into a partial heating load requirement. The 50/50 system allows for P2 to be shut down by an outdoor reset, leaving the system at 50% flow capacity and operating at a 50% pumping reduction. Valves are positioned by the reset schedule or a relay connected to P2.

Outdoor Air - 40°F and Below 60°F
Here is the most striking cost difference between a 50/50 design and a conventional 4-pipe system. Rather that 100% of the chilled and hot water flow being circuited by two pumps rated for 100% of their respective flows, the 50/50 system efficiently delivers 4-pipe capacity with half of the pumping requirement. The unnecessary full flow requirement during a marginal day is eliminated. The chiller is brought on line by outdoor reset. Valves are also positioned by the outdoor reset schedule or a delay connected P2.

Outdoor Air - 60°F to 80°F
When heating is no longer required, the boiler is shut down along with P1. Since only a partial cooling load is required, P2 circulates 50% of the total flow. Valves are positioned by the outdoor reset schedule or a relay connected to the pumps.

Outdoor Air - 80°F and Above
Design day cooling allows for both P1 and P2 to be operating in parallel delivering 100% of the chilled water flow. Valves are positioned by the outdoor reset schedule or a relay connected to the pumps.

The 50/50 system allows design day operating costs to be incurred only when necessary. By using half of the normal main size, with a double Riser Heat Exchanger in each unit, the 50/50 system delivers only the load required for each season, substantial reducing installation and operating costs.

Remember:
The pumps on a 50/50 system are up to 50% smaller than those found on a conventional 4-pipe system.

Up to 85% of the time a fan coil unit is operating at less than full capacity. The 50/50 system allows you to realize significant operational savings during this time.

Features and Benefits
Low Energy Consumption = Low Operating Costs
Left, Right, Front, Back and Top Combinations. All supply openings are painted black to block the view into the unit and when one unit is used for two rooms, a sight baffle is placed between the two grilles.

• Twos fans per unit - Fans are staged to operate when needed. At most conditions, only one fan is operating to provide room conditioning.
• Two pump loops per system - Intermediate seasons often allow one pump to be shut off. Due to the sizing of the unit to meet the required cooling load, only one pump is needed for heating in most circumstances.

By utilizing a reset schedule, the Whalen system will provide 100 percent of the required heating and cooling for the application. This also shuts down pumps when environmental conditions permit to further save energy. Most buildings run at peak capacity for only a few weeks a year. The 50/50 unit takes advantage of this fact by using smaller pumps that can be staged to run fewer hours than a single larger pump. When you couple this with the operation of only one of the two fans during part of the year, you achieve significant energy savings. The unit is practically maintenance-free with only the filter requiring periodic replacement or cleaning. You also will not find the control valves and piping joints that can lead to leaks and service calls.

Lower Installed Costs
Overall system main size is reduced by 50 percent since each side of a 50/50 unit handles 1/2 of total cooling requirement. This means smaller standard pumps and reduced labor times. By design, each unit is naturally balanced once flow is established in the riser. The balancing and venting of individual units is a task of the past. You get the benefits of a reverse return balancing system without the need to run an express riser within the building.

Valve Control Vs. Fan Cycle Control
If power consumption is the #1 feature of a unit, why is a continuously running fan recommended over fan cycling? Whalen takes the common sense approach on this issue. Most households select fan cycling control when offered the option of both systems. If a continuous running fan is preferred, then power consumption is not the primary concern. Whalen offers both types of systems to the customer.

Condensation and/or moisture are formed on the fins of any fan coil unit when high humidity (dewpoint) levels are allowed to exist in the surrounding space. The riser heat-exchanger system continuously dehumidifies the room air by allowing the chilled water coil to be active at all times. Units incorporating control valves to shut off the chilled water supply allow residential moisture formed during the dehumidifying process to re-evaporate into the airstream. The phenomenon is expedited when the fan is allowed to run continuously.

Due to the dual fan arrangement of the Whalen 50/50 unit provided superior dehumidifying at low load conditions typically found during intermediate seasons. By having a fan/coil combination more closely matched to the lower room load, the unit runs longer to remove moisture from the air. At these conditions, a unit with a single fan and water coil will cool the room to the setpoint temperature to quickly achieve adequate moisture removal.

Return Air Opening
The Whalen return air opening with an architectural aluminum grille is sized for easy removal of the fan motor and blower assembly. Unlike a unit with ball valves, flow control valves, balancing valves and coil with numerous joints, the return opening does not have to be enlarged and covered with a steel access panel. Whalen also offers hinged aluminum return air grilles that allow for changing the filter without the use of tools.

100% Cooling/Heating
The Whalen system is designed for energy savings and unit simplicity. By utilizing a reset schedule, the Whalen system will provide 100 percent of the required heating and cooling for the application. This can also permit pumps to be shut down when environmental conditions permit to further save energy.

Increased Reliability
By designing the 50/50 unit with two equally sized heat exchangers, 50 percent system redundancy is provided during peak heating and cooling season.

Advantages For Building Owners
• Reduced operating costs: Each side of the unit can operate independently yielding energy savings from reduced pumping and fan horse power usage.
• Elimination of all electric valves, dampers and flow control valves
• Absence of brazed joints within the cabinet
• Low maintenance (filter change only): No valves, permanently lubricated
• Quiet operation
• Four pipe control during intermediate Seasons
• Aesthetics: Aluminum Grilles - No unsightly steel panels or access openings

Advantages For Contractors
• No unit balancing or reverse return piping
• No venting of individual units
• Supply/return main costs are reduced due to 50% performance capability
• Reduced number of solder joints
• Small riser/drain grouping (10 inch core drill)
• Galvanized cabinet is ideal for direct drywall application (No framing)
• Uniform riser pipe sizing simplifies distribution of units in a building
• Units can be installed early in the construction cycle