Roof Top Unit Overview (MAGNUM)

Visit us at www.mcscontrols.comRevision- 04/21/23

RTU Magnum

Joins the Magnum family of software:-HVAC (and LWC)-CENT-REFR

MCS-CONNECT

MCS-CONFIG

All Magnum software is supported by a common MCS-CONNECT for Communications and MCS-Config to build the units profile.

All software indicates the current state of the system.

RTU Magnum Purpose

Purpose is to provide flexible control to roof top units that provide heating, cooling and dehumidification to a building.

Plus the necessary ventilation control of fans and dampers, to insure proper air quality and building pressure.

Plus the necessary ventilation control of fans and dampers, to insure proper air quality and building pressure.

MCS RTU Magnum

• Supports up to 80 Relay Outputs

• Supports up to 112 Sensors Inputs • Supports up 28 Analog Outputs

• Supports 255 Set points

• Supports storage of last 100 alarms (plus extended info for safety alarms)

• Supports 1008 History Samples for all inputs & outputs

RTU Magnum Safeties

- All HVAC safeties & preventive action are active.

- Individual safeties are provided for each fan, damper, etc.

- Smoke & fire safeties which also provide the ability to purge the building,

- Clogged filter safeties

- Energy Recovery Wheel safeties

RTU Magnum Modes

Modes of operationScreen Shows Ventilation Settings in MCS-CONFIG

- Ventilation

- Cooling

- Heating

- Dehumidification

The sensor control of the modes are selected independently based upon associated set points or a digital input can be selected to ‘Force’ that mode to be active if it is on.

The control sensor for ‘Switch to Cooling/Heating’ will keep the unit in the Ventilation Only mode or enable the other modes.

RTU Magnum Occupied/Unoccupied

- Occupied can be indicated based on a schedule or digital input

- Unoccupied can be over ridden with an override indicator

Status:

-Occupied, set point values.

-Unoccupied, set point values adjusted with night set back

-Override, same as occupied

RTU Magnum Cooling Mode

This mode is based upon the existing HVAC control functions to control compressors and their safeties. The controlling sensor is selected in the General Info screen.

- 20 circuits

- Various types of Compressors & refrigerant types

- Etc. same as HVAC.

Also added a Digital Scroll type of Analog Output. If selected less than 10% will provide 0 voltage output. 10 to 100% will be proportional between 1.5 to 5.0 voltage output.

RTU Magnum Heating Mode

This mode provides either 1 or multiple steps of heating. The controlling sensor is independent from other modes.

The types of heating can be:-Direct Fire (up to 6 valves)-Modulating Gas (up to 6 valves)-Modulating Hot Water-Split Manifold (up to 6 valves)-(above types of heating support Auxiliary Heating)-Modulating SCR (VFD & up to 30 steps)-On/Off Hot Water (up to 30 steps)-Staged Gas (up to 30 steps)-Staged Electric (up to 30 steps)

If multiple steps, current step must be at maximum capacity before next step is allow to start.

RTU Magnum Condenser InfoIn this screen the following is specified:-Condenser Type, this will be the same options as HVAC.

RTU Magnum Dehumidification Mode

Area is too moist, humidity needs to be reduced. In this mode a fixed number of cooling stages are indicated. Only cooling stages that have reheat capability are allowed on. Cooling will reduce the humidity in the air. If heating is required the cooling

stages reheat will be used.

The types of reheat are:-Modulating-Fixed Step (number will be provided)-None

A Return Air Bypass Damper can also be controlled.

If additional heating is required the heating specified for the heat mode can be used, this is an option.

RTU Magnum Humidification Mode

Area is too dry, need to increase humidity.

When the system is NOT in cooling mode, humidity can be increase by modulating a Steam/Mist valve.

The control sensor is specified and based upon a set point the associated analog VFD will be modulated.

RTU Magnum Ventilation Information

Individual control can be specified for:

-Building PSI

-Supply Fan

-Exhaust Fan

-Return Fan

-Outside Air Damper

-Exhaust Damper

-Relief Damper

-Energy Recovery Wheel

RTU Magnum Ventilation Fan Options

- Building PSI: control can be either Direct, Reverse, or Not Used- Supply Fan: (control on Building Static PSI)

- Always On ( applies only if Occupied)- Cycle (on if heating or cooling needed)- Set up as modulating or fixed on/off- Can have 1 or 2 fans

There is a pre-delay, post delay on the supply fan and once on a delay before heating or cooling steps can be turned on.

Exhaust Fan: (control on Duct Static PSI)- Set up as modulating or fixed on/off

Return Fan: (control opposite of supply fan)- Set up as modulating or fixed on/off

RTU Magnum Ventilation Damper Options

Outside Air Damper:

Set up as modulating or fixed on/off

Control can be based upon:-Local minimum fresh air requirement-Level of CO2-CFM (air movement)-Building Static PSI- Will provide economizer cooling as first stage of cooling if ambient temperature is less than the set point value to allow free cooling.

Report on Fault Detection & Diagnostics (based upon California Energy Commission requirements)

RTU Magnum Energy Recovery Wheel

Purpose is to capture potential lost energy by using the leaving air temperature to precondition the incoming fresh air.

During the warmer seasons, the system pre-cools and pre-heats in the cooler seasons.

The Energy Recovery wheel relay can be active when the supply fan is on and the system is not in economizer (free cooling) state.

A Bypass Damper can also be controlled

When on for a given period of time a defrost cycle will be initiated if the outside temperature is less than the defrost temperature.

MCS RTU Magnum

Review MCS-Configuration with RTU set up.