Carrier Aquasnap 30RW Installation, Operation And Maintenance Instructions

Contents

Carrier Aquasnap 30RW Installation, Operation And Maintenance Instructions Manual pdf 21 page image

21The mesh size of the filter must be 1.2 mm. If this filter isnot installed, the plate heat exchanger can quickly becomecontaminated at the first start-up, as it takes on the filterfunction, and correct unit operation is affected (reducedwater flow due to increased pressure drop).Before the system start-up verify that the water circuits areconnected to the appropriate heat exchangers (e.g. no reversalbetween evaporator and condenser).Do not introduce any significant static or dynamic pressureinto the heat exchange circuit (with regard to the designoperating pressures).Before any start-up verify that the heat exchange fluid iscompatible with the materials and the water circuit coating.In case additives or other fluids than those recommended byCarrier are used, ensure that the fluids are not considered as agas, and that they belong to class 2, as defined in directive97/23/EC.Carrier recommendations on heat exchange fluids:1. No NH 4+ ammonium ions in the water, they are verydetrimental for copper. This is one of the most importantfactors for the operating life of copper piping. Acon-tent of several tenths of mg/l will badly corrodethe copper over time (the plate heat exchangers usedfor these units have brazed copper joints).2. Cl- Chloride ions are detrimental for copper with a riskof perforations by corrosion by puncture. If possiblekeep below 10 mg/l.3. SO42- sulphate ions can cause perforating corrosion, iftheir content is above 30 mg/l.4. No fluoride ions (<0.1 mg/l).5. No Fe2+ and Fe3+ ions with non negligible levels ofdis-solved oxygen must be present. Dissolved iron < 5mg/l with dissolved oxygen < 5 mg/l.6. Dissolved silicon: silicon is an acid element of waterand can also lead to corrosion risks. Content < 1mg/l.7. Water hardness: > 0.5 mmol/l. Values between 1 and2.5 can be recommended. This will facilitate scaledeposit that can limit corrosion of copper. Values thatare too high can cause piping blockage over time. Atotal alkalimetric titre (TAC) below 100 is desirable.8. Dissolved oxygen: Any sudden change in water oxygena-tion conditions must be avoided. It is as detrimental todeoxygenate the water by mixing it with inert gas as itis to over-oxygenate it by mixing it with pure oxygen.The disturbance of the oxygenation conditionsencourages destabilisation of copper hydroxides andenlargement of particles.9. Specific resistance – electric conductivity: the higher thespecific resistance, the slower the corrosion tendency.Values above 30 Ohm·m are desirable. A neutralenvironment favours maximum specific resistancevalues. For electric conductivity values in the order of20-60 mS/m can be recommended.10. pH: Ideal case pH neutral at 20-25°C7 < pH < 86.4.2 - field control wiringRefer to the 30RW/RWA Pro-Dialog Plus Controls IOMand the certified wiring diagram supplied with the unit forthe field control wirting of the following features:• Evaporator pump interlock (mandatory). Unitwithout hydronic module• Remote on/off switch• Remote heat/cool switch• Demand limit external switch 1• Remote dual set point• Alarm report by circuit• Evaporator pump control. Unit without hydronicmodule.• Condenser pump control. Unit without hydronicmodule.7 - WATER CONNECTIONSFor size and position of the heat exchanger water inlet andoutlet connections refer to the certified dimensional drawingssupplied with the unit. The water pipes must not transmitany radial or axial force to the heat exchangers nor anyvibration.The water supply must be analysed and appropriate filtering,treatment, control devices, isolation and bleed valves andcircuits built in, to prevent corrosion, fouling and deteriora-tion of the pump fittings. Consult either a water treatmentspecialist or appropriate literature on the subject.7.1 - Operating precautionsThe water circuit should be designed to have the leastnumber of elbows and horizontal pipe runs at different levels.Below the main points to be checked for the connection:• Comply with the water inlet and outlet connectionsshown on the unit.• Install manual or automatic air purge valves at all highpoints in the circuit(s).• Use a pressure reducer to maintain pressure in thecircuit(s) and install a safety valve as well as an expan-sion tank. Units with hydronic module include thesafety valve and expansion tank.• Install thermometers in both the entering and leavingwater connections.• Install drain connections at all low points to allow thewhole circuit to be drained.• Install stop valves, close to the entering and leavingwater connections.• Use flexible connections to reduce the transmission ofvibrations.• Insulate all pipework, after testing for leaks, both toreduce thermal leaks and to prevent condensation.• Cover the insulation with a vapour barrier. If theexternal water piping to the unit is in an area wherethe ambient temperature can fall below 0°C, it shouldbe insulated and an electric heater should be installedon the piping.NOTE: For units without hydronic module a screen filtermust be installed as close as possible to the heat exchangerand in a position that is easily accessible for removal andcleaning. Units with a hydronic module are equipped withthis filter.