Carrier OMNIZONE 50BV020-064 Installation And Service Instructions Manual

Also see for OMNIZONE 50BV020: Operating and troubleshooting guide

Contents

21Step 4 — Make Piping ConnectionsCONDENSER WATER PIPING (Water-Cooled Only) —Always follow national and local codes when installing waterpiping to ensure a safe and proper installation. Connections tothe unit should incorporate vibration eliminators to reducenoise and vibration to the building, and shutoff valves to facili-tate servicing.Prior to connecting the unit(s) to the condenser watersystem, the system should be flushed to remove foreignmaterial that could cause condenser fouling. Install a screenstrainer with a minimum of 20 mesh ahead of the condenserinlet to prevent condenser fouling and internal condenser tubedamage from foreign material.Supply and return water piping must be at least as large asthe unit connections, and larger for long runs. Refer to theSystem Design Manual, Part 3, and standard piping practice,when sizing, planning, and routing water piping. See dimen-sion drawings (Fig. 2-14) for water connection sizes andlocations.Units are furnished standard with a copper heat exchanger.A cupronickel heat exchanger is also available as afactory-installed option. Copper is adequate for closed loopsystems where good quality water is available. In conditionswhere scale formation or water treatment is questionable, theoptional cupronickel heat exchanger should be used. Where thewater is especially corrosive or could lead to excessive fouling,intermediate plate frame heat exchangers are recommended.The unit is capable of operating with entering water temper-atures as low as 50 F, without the need for head pressurecontrol. If the entering water temperature is expected to belower, or more stable unit operation is desired, a field-suppliedwater-regulating valve may be used.This unit has multiple independent refrigerant circuits withseparate condensers. The individual condensers are manifoldedtogether on the waterside to provide easy, single-point waterconnections. In order to achieve proper head pressure controlwhen a water-regulating valve is used, a temperature-actuatedvalve is recommended. This allows any of the independentrefrigerant circuits to operate while still modulating condenserwater flow in response to loop water temperature.A glycol solution should be used if ambient temperaturesare expected to fall below freezing or if the loop water temper-ature is below 50 F while operating in the reverse cycle heatingmode (heat pump units only). Refer to Table 4, whichlists freezing points of glycol at different concentrations. Aminimum concentration of 20% is recommended. Waterpressure drop will increase and unit performance will decreasewith increasing glycol concentrations.Units with factory-installed waterside economizers havecooling water passing through the economizer and condenserin series while operating in the economizer mode. Duringnormal operation, water bypasses the economizer coil.Table 4 — Glycol Freezing PointsAll manual flow valves used in the system should be of theball valve design. Globe or gate valves must not be used due tohigh pressure drops and poor throttling characteristics.Do not exceed recommended condenser fluid flow ratesshown in Tables 5A and 5B. Serious damage or erosion of theheat exchanger tubes could occur. Piping systems should notexceed 10 fps fluid velocities to ensure quietness and tube wallintegrity. Refer to Tables 5A and 5B for condenser water pres-sure drop versus flow rate. Flow rates outside of the publishedrange should not be used.Ball valves should be installed in the supply and return linesfor unit isolation and water flow balancing.CAUTIONGalvanized pipe or fittings are not recommended with50BV units due to the possibility of galvanic corrosioncaused by dissimilar metals. When selecting pipingmaterials, use only approved piping materials that meetapplicable codes and that will handle the temperatures andpressures that may be experienced in the application.Piping systems will sweat if low temperature fluid is usedin the system. For these applications, supply and returnwater piping should be insulated to protect from condensa-tion damage. The minimum recommended entering watertemperature to the unit is 50 F.% GLYCOL FREEZE POINT (° F)Ethylene Glycol Proplylene Glycol20 18 1930 7 940 –7 –550 –28 –27Fig. 19 — DHS Limit Switch (P/N 190060)a50-7268tfFig. 18 — DHS Pressure Limit Locationa50-8253