explosion proof air conditioning
BIRDWELL MODEL BAR SINGLE STAGE ROOF MOUNT
AIR conditioning systems
INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS
INTRODUCTION:
The Birdwell environmental control units were originally designed for world-wide use on offshore oil drilling and producing platforms. In approximately twenty years of use in this harsh environment, the rugged corrosion resistance and reliability of the systems were proven to be significantly superior to the units that were designed for commercial and residential use. Since that time, users such as refineries, steel mills, chemical plants, pulp and paper plants, ocean going vessels and others having similar problems with corrosion and/or hazardous conditions have found the Birdwell environmental control systems to be tough and dependable.
The fundamental guidelines used in designing the systems were unrestricted serviceability and ease of installation. Also of prime importance were reliability, safety and resistance to corrosion. As a result of this criterion, many believe these to be the finest units available for the intended market.
All cabinets and other sheet metal parts are constructed of not less than 16 gauge galvanized paint grip metal (doors are double wall, BAR base pans are 11 gauge steel) with two coats of polyurethane paint as standard. Parts most subject to corrosion such as drain pans and exterior grilles are furnished in stainless steel as standard. Stainless steel cabinets are optionally available. Coils and piping are coated with epoxy or high bake phenolic. The units are available in several explosion proof configurations. For a complete list of standard features and options, see the applicable brochure.
ROOF MOUNT:
If unit is to be roof mounted, check with the building manufacturer and any applicable building codes for weight distribution requirements. Refer to BAR brochure for physical and dimensional data.
The roof mounting curb (customer provided) for the Birdwell model BAR air conditioning unit should be carefully sealed where the return and supply ducts are attached. The top surface of the curb should be straight and level with a minimum 1/4" thick closed cell foam gasket attached to provide a positive seal between the air conditioning unit and the duct system. This is very important in this type of system since even small leaks can cause great losses of conditioned air.
RIGGING AND PLACEMENT:
The packaged, self contained BAR unit has lifting eyes at the top for convenient rigging. The eyes are threaded to 3/4" pipes that are welded to the base pan of the unit.
Attach wire rope slings to the lifting eyes. Lift slightly to check level and security of slings. After any necessary sling adjustments are made, gently lift the unit to a position directly over the curb, then slowly lower straight down making sure that the gasketed surface of the curb is not damaged. After the unit is in place over the curb, it may be, if desired, secured through the sides of the base pan into the curb using self tapping screws.
POSITIONING:
Unit condenser air inlet and outlets may be located in any direction as the unit is not affected by wind direction. Provide adequate clearances around and above the unit for unrestricted air flow, safety and service access. Do not locate the unit near exhaust vents or other contaminated air sources if it is equipped with an optional fresh air vent or pressurization system (with the air inlet at this location).
INSTALLATION:
CAUTION: Before making any electrical connections or performing any maintenance, make sure all power switches pertaining to this equipment are turned off and locked. In addition to the danger of electrical shock, the fan motors have internal overload protection that could restart a fan without warning and cause serious injury! Also, before energizing any of the electrical equipment or making the initial start up of the system, make certain the ambient atmosphere is safe (non-hazardous).
Consult local codes or ordinances for specific requirements regarding installation and the termination point of the condensate drain. A trap must be installed in the drain line to prevent the entrance of outside air.
If the unit is in a hazardous (classified) location, the drain must be extended to a safe location to preclude the possibility of the trap drying out in the heating season and allowing the entrance of contaminated air.
ELECTRICAL:
Field wiring must comply with the latest applicable articles of the National Electrical Code and the requirements of the United States Coast Guard in the case of offshore drilling/producing platforms or ocean going vessel use. Wiring should be performed only by a qualified electrician.
In hazardous locations install and pour seals between the unit and all connecting conduit. Refer to articles 500 and 501 in the National Electrical Code for specific requirements.
Size conductors using the data supplied on the nameplate. Use only copper conductors. Be certain the available voltage matches the data on the nameplate. A disconnecting means must be within sight from and readily accessible from the unit.
The unit must be securely grounded to the grounding lug provided in the main control panel.
Thermostat connections are low voltage (24 volts). Refer to the unit wiring schematic and the thermostat instruction sheet.
The thermostat is one stage cooling and one stage heating type (if optional heaters are ordered with the unit).
Select a location on an inside wall (if possible) away from drafts or dead air spots behind doors and corners, hot or cold air ducts, radiant heat from the sun or electrical equipment, or unheated areas behind the thermostat wall.
Mount the thermostat about five feet (1.5 meters) above the floor in an area of good air circulation. The thermostat must be level if it is the mercury switch type (not suitable for shipboard use). Refer to instructions supplied with the thermostat for detailed instructions.
DUCTING:
The duct system should be installed in accordance with the American Society of Heating, Refrigerating And Air Conditioning Engineers, Inc. (ASHRAE) standards. Connections to the roof curb should be made before the unit is set in place. It is recommended that a filter grille be installed in a convenient and accessible location. It should contain minimum 1" thick disposable fiber glass filters. A good rule of thumb for size would be one square foot of filter surface area per ton of air conditioning.
SCOPE OF OPERATION:
All Birdwell Model BAR series of air conditioning units are single package self contained systems. These systems are designed for one or two stage cooling (depending upon the model) and optional one or two stage electric heating.
After the unit, ductwork, low and high voltage wiring have been installed and the thermostat in place, set the thermostat system switch to the "off" position and the fan switch to the "auto" position. Then switch the main power to the unit on after referring to the "caution" paragraph under the installation heading.
Do not start the unit for a period of twenty-four hours to allow time for the compressor crank case heater to vaporize any liquid refrigerant that may have accumulated in the crank case during storage. CAUTION: Failure to observe this precaution could result in serious damage to the compressor valves and/or bearings. After the twenty-four hour period has elapsed the unit may be started in the cooling mode.
START UP PROCEDURE:
This procedure should be performed only by a qualified air conditioning technician:
Step 1: Double check the voltage supplied to the unit to confirm that it matches the nameplate requirements.
Step 2: Set the thermostat fan switch in the "on" position, then check the unit to see if only the evaporator blower is running, then set the switch back to the "auto" position.
Step 3: Set the thermostat system switch in the "cool" position.
Step 4: Set the thermostat to a setting slightly below the indoor temperature, then check to see if the compressor is running.
Step 5: At this point amperage readings should be taken on the compressors and motors to see if they conform to nameplate ratings.
Step 6: Set the thermostat system switch to the "heat" position (if the unit has this option).
Step 7: Set the thermostat above the room temperature, then check to see if the heat is operating.
Step 8: Set the thermostat system switch to the "auto" position (if this option is present), then set for the desired operating temperature.
MAINTENANCE:
NOTE: All maintenance should be performed by a qualified air conditioning/heating mechanic.
MOTORS All fan and blower motors on the system are the sealed bearing type and permanently lubricated, therefore no maintenance of the motors is required.
BLOWERS The blowers and fans on the standard units are direct drive, so there are no belts to service. It is recommended that at least once a year (more often in very dirty locations) the blower wheel be inspected and cleaned if necessary using a wire brush and vacuum cleaner.
FILTERS Filters should be checked at least once per month, or more frequently in dirty air conditions, and cleaned or replaced as necessary.
COMPRESSOR The compressor is hermetically sealed and factory charged with oil, so no maintenance is necessary.
CONDENSER/ The condenser coil should be cleaned at least once a year (more
EVAPORATOR often in dirty locations) using a good commercial coil cleaning
COILS agent. This is very important to maintain top efficiency and to prolong compressor life by keeping operating pressures within normal limits. The evaporator coil should be inspected at the same time and cleaned in the same manner if needed.
CONDENSATE The condensate drain pan and drain line should be checked and
DRAIN cleaned at a minimum of twice yearly, or more often if found to be necessary.
REFRIGERANT The system is factory charged with refrigerant and should not re-
CHARGE quire adjustment. The sight glass will show some bubbling in very hot or very cold conditions and are not necessarily indicative of a need for additional refrigerant.
If at any time the system should need an addition of refrigerant, it should be added very carefully and only by qualified personnel. Use only refrigerant 22!
NOTE: Whenever maintenance is being performed on this equipment whereby the refrigerant system may be opened up to the atmosphere, proper procedures for handling system refrigerant must be followed according to the Environmental Protection Agency (EPA). Please refer to Title 40 of the Code of Federal Regulations, Part 82 for EPA regulations.
If the system is low on refrigerant and the system still has considerable pressure, the entire piping circuit should be checked and the leak located and repaired before any refrigerant is added.
If the system is completely void of pressure, it should be pressurized, the leak located and repaired, then a new liquid line drier be installed.
After this is done, a good vacuum pump should be connected to the system and a run for several hours to remove any possible moisture that could be present. After the vacuum has been pulled, weigh in the proper charge according to the data on the nameplate.
If any problem is encountered that is not covered in these instructions, or for any question that might arise, call The Birdwell Company in Houston Texas (281) 492-1786.