Roberts Gorden CTU 22 TO 115 service manual AIR Supply

COMBAT® CTU UNIT HEATERS INSTALLATION OPERATION AND SERVICE MANUAL

SECTION 7: AIR SUPPLY

7.1 Room Sealed Installation

When installed as a room sealed heater, the air for combustion is drawn in from outside the building. It is important to ensure that there is adequate ventilation to provide air for the distribution fan/s.

7.2 Open Flued Installation

It is important to ensure that there is adequate air supply at all times for both combustion and heating requirements in accordance with local and national codes. When installed in this mode, the air supply to the heater must also be fitted with a low resistance terminal to prevent the ingress of debris. See Page 11, Figure 5.

7.2.1 Heaters Installed Within the Heated Space

Where the volume of the heated space is greater than 4.7 m3 per kilowatt of total rated heat input and the air change rate is at least 0.5/h, additional high and low level ventilation will not be required.

For a building having an air change rate less than 0.5/h, ventilation will be necessary in accordance with local and national codes. Ventilation direct to outside must be provided as follows:

•Heaters up to 70 kW heat input: 5.0 cm2 per kW of rated heat input

•Heaters above 70 kW heat input: 350 cm2 + 2.5 cm2 per kW of rated heat input above 70 kW

7.3 Building Ventilation

Where ventilation is required, air must be taken from an outside point where it is not likely to be contaminated or obstructed.

Where natural ventilation is used, suitable ventilation with outside air at low level must be provided in accordance with Section 7.2.1 and local and national codes.

Where mechanical ventilation is used, extract rate must be 5% - 10% less than the inlet rate. The mechanical ventilation must be interlocked with the burner on the CTU heater.

7.4 Isolated Equipment Rooms

Ventilation must prevent the isolated equipment room temperature from exceeding 32° C as well as prevent any negative air pressure within the room. See Page 12, Figure 7. Any isolated equipment room containing air heaters will require permanent air vents direct to outside air in compliance with local codes.

Where natural ventilation is used, suitable permanent openings at low and high level, communicating directly with the outside air, must be provided.

Where mechanical ventilation is used, extract rate must be 5% - 10% less than the inlet rate. The mechanical ventilation must be interlocked with the burner on the CTU heater.

Figure 7: Heaters Installed in Isolated Equipment Rooms

Duct Distribution

System or

Discharge to Heated Space

	High Level
Manifold	Ventilation
Air Intake	Flue

Return Air Duct

from Heated

Space or Fresh

Air from Outside

Max Temperature 32° C

Room Air Pressure Must Not be Negative.

Wall

Low Level

Ventilation

Outside

Wall

12