Armfield Ra2 User manual

An ISO 9001 Company

INSTRUCTION MANUAL

RA2

ISSUE 2

September 2009

Air Conditioning Unit RA2

RA2 Air Conditioning

IMPORTANT SAFETY INFORMATION

All practical work areas and laboratories should be covered by local safety regulations

which must be followed at all times.

It is the responsibility of the owner to ensure that all users are made aware of relevant local

regulations, and that the apparatus is operated in accordance with those regulations. If

requested then Armfield can supply a typical set of standard laboratory safety rules, but

these are guidelines only and should be modified as required. Supervision of users should

be provided whenever appropriate.

Your Air Conditioning Unit RA2 has been designed to be safe in use when installed,

operated and maintained in accordance with the instructions in this manual. As with any

piece of sophisticated equipment, dangers may exist if the equipment is misused,

mishandled or badly maintained.

Electrical Safety

The equipment described in this Instruction Manual operates from a mains voltage

electrical supply. It must be connected to a supply of the same frequency and voltage as

marked on the equipment or the mains lead. If in doubt, consult a qualified electrician or

contact Armfield.

The equipment must not be operated with any of the panels removed.

To give increased operator protection, the unit incorporates a Residual Current Device

(RCD), alternatively called an Earth Leakage Circuit Breaker, as an integral part of this

equipment. If through misuse or accident the equipment becomes electrically dangerous,

the RCD will switch off the electrical supply and reduce the severity of any electric shock

received by an operator to a level which, under normal circumstances, will not cause injury

to that person.

At least once each month, check that the RCD is operating correctly by pressing the TEST

button. The circuit breaker MUST trip when the button is pressed. Failure to trip means

that the operator is not protected and the equipment must be checked and repaired by a

competent electrician before it is used.

Heavy Equipment

This apparatus is heavy.

•The apparatus should be placed in a location that is sufficiently strong to support its

weight, as described in the Installation section of the manual.

RA2 Air Conditioning

•When lifting is required, two or more people will be required for safety. All should

be made aware of safe lifting techniques to avoid strained backs, crushed toes, and

similar injuries.

•Safety shoes and/or gloves should be worn as appropriate.

Hot Liquids and Steam

This apparatus contains steam and hot water at temperatures capable of causing scalds.

•Always allow time for the apparatus to cool before disassembly.

•Avoid skin contact with hot water and steam. Take particular care if refilling the

apparatus during use. Be aware that the flow of hot steam can extend for some

distance and may not be visible.

•Ensure that the outlet is directed away from anything that could be harmed by

raised temperatures or damp air.

•Always operate the apparatus according to the Operational Procedures described in

this manual.

•Use only those fluids described in this manual when setting up and operating this

equipment.

Hot Surfaces

This apparatus is capable of producing temperatures that could cause burns.

•The apparatus should not be left unattended while switched on.

•Do not touch any surfaces with a ‘Hot Surfaces’ warning label.

•Do not allow the apparatus to come into contact with flammable materials or

liquids.

•Allow enough time for the equipment to cool before handling any of the

components.

•Do not cover or store the equipment until it has cooled.

•Any safety guards or insulated covers are there for operator protection- they must

not be removed except as described in this manual,.

•Always operate the apparatus according to the Operational Procedures described in

this manual.

Moving and Rotating Components

This apparatus has a rotating fan.

•Do not remove any protective guards while the equipment is in operation.

RA2 Air Conditioning

•Long hair should be tied back out of the way and dangling items such as necklaces,

scarves or neckties should be removed or secured so that they cannot become

entangled in the equipment.

•Do not touch or insert any object into any moving component while the apparatus is

in use.

•Ensure that the apparatus is switched off and that all moving parts have come to

rest before handling the equipment, except as described in the Operational

Procedures section of this manual.

High Pressures

A component within this apparatus (the refrigeration unit) is designed to operate with

internal pressures greater than that of the surrounding atmosphere.

•Do not attempt to pierce or open any part of the refrigeration unit.

•Ensure the unit is positioned so the pressure relief valve is pointed in a safe

direction.

•Keep the external temperature above 0°C and below 40°C.*

•Protect the unit from damage.

*Temperatures for storage only. The operational range is described in the Operation section

of this manual.

Water Borne Hazards

The equipment described in this instruction manual involves the use of water, which under

certain conditions can create a health hazard due to infection by harmful micro-organisms.

For example, the microscopic bacterium called Legionella pneumophila will feed on any

scale, rust, algae or sludge in water and will breed rapidly if the temperature of water is

between 20 and 45°C. Any water containing this bacterium which is sprayed or splashed

creating air-borne droplets can produce a form of pneumonia called Legionnaires Disease

which is potentially fatal.

Legionella is not the only harmful micro-organism which can infect water, but it serves as a

useful example of the need for cleanliness.

Under the COSHH regulations, the following precautions must be observed:-

•Any water contained within the product must not be allowed to stagnate, i.e. the

water must be changed regularly and drained if the equipment will not be in use for

some time.

•Any rust, sludge, scale or algae on which micro-organisms can feed must be

removed regularly, i.e. the equipment must be cleaned regularly.

RA2 Air Conditioning

•Where practicable the water should be maintained at a temperature below 20°C. If

this is not practicable then the water should be disinfected if it is safe and

appropriate to do so. Note that other hazards may exist in the handling of biocides

used to disinfect the water.

•A scheme should be prepared for preventing or controlling the risk incorporating all

of the actions listed above.

Further details on preventing infection are contained in the UK publication “The Control of

Legionellosis including Legionnaires Disease” - Health and Safety Series booklet HS (G)

70.

Refrigerant R134a

This equipment incorporates a sealed unit containing refrigerant R134a (Also known as:

HFC-134a; 1,1,1-2 Tetrafluoroethane; Norflurane; Norfluran). This is a common

refrigerant introduced to replace CFC (chloro-fluoro-carbon) refrigerants such as R-12.

R134a is colourless, nonflammable and noncorrosive with a very faint odour. In the RA2 it

is contained within a completely sealed unit, and is safe under normal use as described in

this manual.

It is the responsibility of the owner to check local regulations regarding R134a and ensure

that these are complied with.

R134a can reach temperatures capable of causing cold burns (frostbite). This may

specifically constitute a hazard if R134a has been cooled and pressurised into liquid form

and then escapes as a liquid through a leak, or experiences sudden expansion (as may

happen if the sealed unit is pierced) forming a jet of cold vapour.

R134a vapour may cause irritation of the eyes and mild irritation of the skin. It is relatively

non-toxic if inhaled, but may cause asphyxiation if inhaled in sufficient concentration.

In the event of exposure to flames or high temperatures (over 50°C), R134a may break

down into toxic components.

•Do not attempt to open or pierce the sealed unit containing the refrigerant.

•Always operate the equipment within the safe temperature limits described in this

manual.

•In the event that the sealed unit is ruptured, follow local regulations and take

appropriate steps to reduce the potential hazard. As a suggestion only, procedure

may be as follows (local requirements will vary):

oRemove all personnel from the immediate area

oAvoid skin and eye contact with any escaped refrigerant

oExtinguish nearby flames

oIncrease ventilation so that vaporised refrigerant can dissipate harmlessly

RA2 Air Conditioning

In the event of damage to the refrigeration unit, the unit must only be repaired or replaced

by a suitably qualified engineer. Contact Armfield or your local agent for advice.

RA2 Air Conditioning

AIR CONDITIONING UNIT

RA2

Contents

1Introduction to the Equipment......................................................................................................................... 8

1.1 Diagram 1: Front View of Apparatus ........................................................................................................ 9

1.2 Diagram 2: Top View of Apparatus......................................................................................................... 10

2Description ....................................................................................................................................................... 11

2.1 Overview .................................................................................................................................................. 11

2.2 Control Box.............................................................................................................................................. 11

2.3 Axial Fan.................................................................................................................................................. 12

2.4 Pre-heater and Re-heater ........................................................................................................................ 12

2.5 Evaporator ............................................................................................................................................... 13

2.6 Condensing Unit ...................................................................................................................................... 14

2.7 Humidifier................................................................................................................................................ 15

2.8 Air Velocity Sensor .................................................................................................................................. 16

2.9 Temperature / Relative Humidity Sensor ................................................................................................. 17

2.10 Data Logger/Equipment Controller and Software................................................................................... 17

3Operation and Software.................................................................................................................................. 18

3.1 Safety........................................................................................................................................................ 18

3.2 Using the Software................................................................................................................................... 18

3.3 Operation of the Humidifier..................................................................................................................... 19

3.4 Operation of Remote Controller/Data Logger and Software................................................................... 19

3.5 Data Logging Facilities ........................................................................................................................... 21

3.6 USB Interface........................................................................................................................................... 22

4Specifications.................................................................................................................................................... 23

4.1 Overall Dimensions.................................................................................................................................. 23

4.2 Electrical Supply...................................................................................................................................... 23

4.3 Ventilation................................................................................................................................................ 23

4.4 Refrigerant ............................................................................................................................................... 23

4.5 USB Channel Numbers ............................................................................................................................ 24

4.6 Operating Conditions............................................................................................................................... 25

5Routine Maintenance ...................................................................................................................................... 26

RA2 Air Conditioning

5.1 General..................................................................................................................................................... 26

5.2 RCD Test ..................................................................................................................................................26

5.3 Calibration of Relative Humidity Sensors................................................................................................26

5.4 Calibration of Temperature and Air Flow Sensors ..................................................................................27

5.5 Cleaning Procedure .................................................................................................................................27

6Background and Theory..................................................................................................................................30

6.1 Background .............................................................................................................................................. 30

6.2 Nomenclature ...........................................................................................................................................31

6.3 Psychrometric chart and Glossary ...........................................................................................................32

6.4 Using Calculations instead of the Psychrometric Chart to Determine the Air State................................34

6.5 Other Calculations Required....................................................................................................................38

7Laboratory Teaching Exercises ......................................................................................................................41

7.1 Exercise A: Psychrometric Charts ...........................................................................................................41

7.2 Exercise B: Sensible Heating ................................................................................................................... 44

7.3 Exercise C: Humidification ......................................................................................................................48

7.4 Exercise D: Cooling with Dehumidification ............................................................................................51

7.5 Exercise E: Enthalpy................................................................................................................................55

8Installation Guide................................................................................................................................................i

8.1 Connection to an electricity supply .............................................................................................................i

8.2 Data logger/remote controller and software...............................................................................................i

9Electrical Wiring Diagram................................................................................................................................ii