Carrier 38AU appendix Installation, Unit Damage Hazard

Same tube sizes are capable of handling higher flowrates (expressed as tons of cooling capacity) with Puron refrigerant compared to R-22 at constant pressure drops. For example, a 1/2-inch OD liquid line is rated at 33% higher tons with PuronR than with R-22 (at 5_F pressure drop). A 1 1/8-inch OD suction line is rated at 53% higher tons with Puron than with R-22 (at 2_F pressure drop). Refrigeration lines selected for R-22 use are typically oversized for Puron applications. Carefully check the existing suction line size against the table for maximum size (see Table 7); replace vertical riser segments if necessary. Check existing liquid line size against sizing data in Table 5 or 6; replace with smaller lines when feasible.

Installation –

1.Remove the existing evaporator coil or fan coil and install the replacement coil when appropriate.

2.Drain oil from low points and traps in suction line tubing (and hot gas bypass tubing if appropriate) and evaporator if they were not replaced. Removing oil from evaporator coil may require purging of the tubing with dry nitrogen.

3.Unless indoor unit is equipped with a Puron→ ap- proved metering device, change the metering device to a thermal expansion valve (TXV) designed for PuronR (R-410A).

4.Remove the existing outdoor unit. Install the new out- door unit according to these installation instructions.

5.Install a new field-supplied liquid-line filter drier at the indoor coil just upstream of the TXV or fix orifice metering device.

6.If a suction line filter drier is also to be installed, in- stall suction line drier downstream of suction line ser- vice valve at condensing unit.

!CAUTION

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment damage or improper operation.

Never install suction-line filter drier in the liquid-line of a PuronR system.

7.If required, install a 100% activated alumina suction line filter drier at the outdoor unit.

8.Evacuate and charge the system according to the in- structions in this installation manual.

9.Operate the system for 10 hr. Monitor the pressure drop across the suction line filter drier. If pressure drop exceeds 3 psig (21kPa), replace suction-line and liquid-line filter driers. Be sure to purge system with dry nitrogen and evacuate when replacing filter driers. Continue to monitor the pressure drop across suction-line filter drier. Repeat filter changes is neces- sary. Never leave suction-line filter drier in system longer than 72 hr (actual time).

38AU

3