AHU’S/PARTS

The housing of the Danann range of Air Handling Units consists of an aluminium penta-post frame and double skin insulated panels, which give excellent thermal insulation and sound reduction. The inner wall of the panel is manufactured from 1.2mm galvanized sheet steel and the outer skin is from PVC coated sheet steel. The thickness of the AHU panels is either 27mm or 52mm thick. The sandwiched insulation is fibreglass and has a density of 60kg/m3.

The hinges on the access doors are heavy duty, black steel hinges. The handles on the unit are lockable latch types, matching the heavy-duty hinges. These latch type door handles provide an excellent door air seal, and there is the option of double glazed reinforced viewing windows within each door.

There is closed cell expanded foam gasket between the AHU panels and the aluminium frame to avoid air leakage and thermal bridging. All units are manufactured to EN 1886 leakage class B.

The standard colour of Danann AHU’s is Goosewing grey. If another colour is required for a particular project, it can be provided.

The base-frame is manufactured from rolled steel channel RSC. It is fully welded, ground smooth and hot dip galvanised after manufacture.

The type of fans most commonly selected for AHU applications are centrifugal belt driven fans. The fans are manufactured by Gebhardt of Germany and are generally double inlet, double width, backward curved, centrifugal fans. The scroll is manufactured from galvanized sheet steel, which is lap jointed and is complete with a discharge flange and adjustable feet.

The impeller of the RZR range contains 12 blades of true aerofoil shape. They are fabricated from galvanized sheet steel, degreased phopsphated and painted. Impellers and shafts are statically and dynamically balanced as a single unit according to VDI 2060 (BS 5265 Part 1: 1979, ISO 1984 – 1986).

Self-aligning double row ball bearings are mounted in cast iron housing and are packed with long life high performance grease. For particular applications, other type fans, such as axial fans, direct driven fans can be offered.

The motors selected are from a number of leading manufacturers whose products meet with European TUV approval. They are totally enclosed, fan cooled, cage induction type motors. They are suitable for a 400V/3-Phase/50 Hz. Electrical supply. The rotor and shaft are dynamically balanced to BS4999 Part 142. All motors to be operated by a variable speed drive are fitted with a thermistor.

The coils are manufactured by FACO (Italy). The coils are manufactured from 5/8 ” diameter copper tubes which are mechanically expanded into aluminium fins. The return bends are copper and the flow and return headers are plain carbon steel. The coil frame is galvanized sheet steel. The steel headers have a threaded male pipe connection and include a drain and a vent. The coil is pressure tested to 30 bar, with a maximum operating pressure of 15 bar. The coils are installed such that the headers and return bends are enclosed by the unit casing, and the protruding connections are sealed to prevent air leakage. All cooling coils are positioned within a stainless steel condensate drain tray. Droplet eliminators are fitted where the air velocity through the fin block exceeds 2.5m/s.

Danann design and manufacture AHU’s with indirect gas fired heating incorporated into the Air Handling Unit. The indirect gas fired heaters will be either on/off or fully modulating as indicated in the technical schedule. The gas burner’s are fully sealed on both the air on and air off sides. The AHU panel enclosing the section containing the gas burner is fitted with an aluminium louvre. This ensures the combustion process is under atmospheric pressure.The gas burners can be operated with either natural gas or propane gas.

Electric heater batteries are manufactured from both stainless steel/ or aluzinc tubes and spiral fin heat elements secured to a galvanised steel frame. The electric heater can be designed for step or modulating control.

Optional safety controls include high temperature cut out switch, and time relay allowing fan to stop approximately 3 minutes after temperature cut out.

All Danann drain trays are custom designed fully welded stainless steel, with tapered turn-ups to suit the lower flange of the coil. The Danann drain trays have a built in corrected fall in two directions to remove water quickly from the AHU. The drain connection is schedule 40 stainless steel threaded weld nipple 42mm Diameter. Care is taken to ensure the invert level of the drain connection is no greater than the invert level of the drain tray and so prevent any ponding or stagnant water in the drain tray.

As standard all filters are loaded from the air on side with full-hinged access door to the section. All Danann filter banks are fitted with a Dwyer magnehelic gauge as standard.

Pre-Filters:
The pre-filters are rated at EU-4 (G4) efficiency according to Eurovent 4/5. Each modular filter cell is complete with its galvanized holding frame. Each frame is complete with 4 No spring clips.

Bag Filters:
Each Modular 592mm x 592mm x 535mm long bag filter is rated at EU-7 or 8 or 9 (F7, F8, F9) efficiency on Eurovent 4/5 standard. Each modular filter cell is complete with its galvanized holding frame. Each frame is complete with 4 No retaining clips.

Minipleat Filters:
Each Modular 592mm x 592mm x 305mm long minipleat filter is rated at EU-7 or 8 or 9 efficiency on Eurovent 4/5 standard. Each modular filter cell is complete with its plastic holding frame. Each frame is complete with 4 No retaining clips.

HEPA Filters:
Each Modular 592mm x 592mm x 305mm HEPA filter is rated at EU-13 or 14 efficiency on Eurovent 4/5 standard. Each modular filter cell is housed in its proprietary steel frame and 4 No spring retaining clamps.

Danann packaged AHU’s are pre-wired and pre-piped in the factory prior to delivery to site. Fan motors are wired in SWA to an external weatherproof isolator for neat external connection on site. Optional light fittings in access section with Vapour-proof bulkhead light fittings pre wired in SWA to external weatherproof light switches for external connection on site. AHU’s can on request include BMS Controls, factory installed wired and commissioned including software loaded and demonstrated prior to delivery.

Danann design, assemble and install on site complete self-contained DX- cooling and heat pump systems; including AHU Multi-circuit Coils, Condensing Unit(s), pipe-work on site, controls, charging and commissioning.

Dampers are of an opposed blade multi-leaf type. Each damper blade is made from extruded aluminium in a true aerofoil shape, (not single skin blades). The blades are coupled internally by means of robust linkages, which are positioned outside the air-stream. The damper casing is punched to house maintenance free nylon bearings and a single drive spindle extended to accept the controlling Damper motor. The frames of the dampers are pre-drilled, suitable for ductwork connection.

All louvers are aluminium lip bladed louvers complete with bird/vermin screen protection.

Each Danann Air Handling Unit is fitted with an individual and traceable Aluminium nameplate, which is riveted to the sidewall of the unit. The label conforms to the CE Machinery Directive 89/392/EEC published by the National Standards Authority of Ireland. Each fan section has a clear safety label reading ‘Danger Isolate Electrical Supply Locally and Ensure Rotation has Completely Stopped before Entry’ fitted at the fan access point. Danann labelling complies with ISO 11684 for hazard warning.