Case Study: Riverton City Park Commercial Rooftop Unit

Case Study: Riverton City Park Commercial Rooftop Unit Replacement

Address area: commercial building near Riverton City Park, Riverton, UT 84065 (specific address confidential per business owner request). Project completion: August 2025. Scope: Commercial packaged rooftop unit (RTU) replacement for approximately 4,200 sq ft restaurant operation, replacing 2003 original construction 7.5-ton RTU with modern high-efficiency Carrier packaged gas/electric unit. This case study documents the pre-installation commercial evaluation, business continuity coordination minimizing restaurant closure time, crane lift coordination for rooftop equipment replacement, commissioning verification for commercial building conditioning, and business owner outcome including operating cost impact analysis.

Project Background

Commercial Building Characteristics

Commercial building housing restaurant operation: approximately 4,200 sq ft occupied space with dining area (2,400 sq ft), kitchen (1,200 sq ft including cooking line and prep area), and support areas (walk-in cooler, freezer, office, restrooms), single-story flat-roof commercial construction typical of 2003 commercial development, and building located in commercial corridor near Riverton City Park with regular customer traffic patterns.

Existing Equipment

2003 original construction packaged rooftop unit:

  • Manufacturer/Model: Trane Voyager YCC090 packaged gas/electric rooftop unit
  • Capacity: 7.5 tons (90,000 BTU/hr cooling), 180,000 BTU/hr gas heating input at 80% AFUE
  • Age: 22 years old at replacement, well beyond typical 15-20 year commercial RTU service life
  • Refrigerant: R-22 refrigerant system (phased out for new equipment, remaining service scenarios use recovered/recycled R-22 at premium cost)
  • Condition: Multiple recent service calls including refrigerant leakage requiring recharge, blower motor bearing noise, and heat exchanger corrosion visible during recent inspection

Pre-Replacement Evaluation

Pre-replacement evaluation confirmed replacement rather than repair: (1) 22 year-old equipment beyond typical service life with cascading component failure pattern; (2) R-22 refrigerant phase-out increases cost of continued service scenarios; (3) 80% AFUE heating and standard cooling efficiency substantially less efficient than modern packaged unit options; (4) recent refrigerant leak indicates aged refrigerant piping and coil condition, likely to produce ongoing repair scenarios; and (5) restaurant operation depends critically on HVAC reliability, and continued patching of aged equipment risks business-disrupting failure during peak dining periods.

Business Continuity Coordination

Restaurant Operation Impact Assessment

Restaurant operation impact considerations: restaurant open 6 days per week (Tuesday–Sunday), lunch service 11am–2pm and dinner service 5pm–9pm daily, weekend brunch service Saturday–Sunday 10am–2pm, and Monday closure day for maintenance and prep. Business owner priority: minimize customer-facing closure time, ideally maintain normal operations with rooftop replacement completed during single Monday closure or overnight window.

Replacement Timeline Planning

Replacement timeline planned as follows: (1) Sunday evening after dinner service close (9pm), equipment staging and pre-work preparation; (2) Monday full-day installation (7am–7pm) with crane lift scheduled 8am–10am window for existing unit removal and new unit setting; (3) Monday evening commissioning verification and cleanup; (4) Tuesday morning normal operations resume with new HVAC system in service.

Temporary Cooling Consideration

August installation timing produced ambient conditions concern for restaurant kitchen operation: kitchen equipment (grill line, fryer, ovens) produces substantial heat load requiring active cooling for cook safety and food safety, cooler than main dining area during summer months, and full day without operational RTU during high summer conditions could produce interior temperatures exceeding safe kitchen operation range. Temporary cooling deployment: two 60,000 BTU portable spot coolers deployed in kitchen prep area during installation day, providing critical cooling for prep work being conducted for Tuesday reopening, and portable spot coolers routed to exterior venting for exhaust heat.

Equipment Selection

Carrier Weathermaker Selection

Carrier Weathermaker 48TC packaged gas/electric rooftop unit selected:

  • Model: 48TCED09 (7.5 ton nominal cooling, 200,000 BTU/hr gas heating input)
  • Cooling efficiency: IEER 14.5 (Integrated Energy Efficiency Ratio, commercial equivalent to SEER for commercial equipment), 32% improvement over 2003 baseline equipment
  • Heating efficiency: 82% thermal efficiency two-stage gas heating (65% low-fire / 100% high-fire operation)
  • Refrigerant: R-410A modern refrigerant (not affected by R-22 phase-out)
  • Compressor: Two-stage scroll compressor providing capacity modulation
  • Blower: VFD (Variable Frequency Drive) blower motor for airflow modulation
  • Economizer: Integrated economizer for free cooling during appropriate outdoor conditions
  • Warranty: 10-year compressor, 5-year parts

Cooling and Heating Load Verification

Commercial load calculation for the restaurant:

  • Cooling load: 78,000 BTU/hr sensible + 24,000 BTU/hr latent (dining area occupancy latent load + kitchen appliance sensible load elevated above general commercial baseline)
  • Heating load: 118,000 BTU/hr at 9°F design temperature (elevated relative to residential per sq ft given commercial ventilation requirements and building envelope characteristics)
  • Ventilation: Restaurant requires substantial outdoor air ventilation per ASHRAE 62.1 commercial standard (approximately 15 CFM per occupant + additional makeup air for kitchen exhaust hood)
  • Equipment sizing verification: 7.5 ton cooling (90,000 BTU/hr nominal, 78,000 BTU/hr sensible with proper CFM matching) matches sensible load with proper diversity for latent handling; 200,000 BTU/hr heating input at 82% thermal efficiency provides 164,000 BTU/hr output, altitude-corrected to ~146,000 BTU/hr, comfortably above 118,000 BTU/hr calculated load

Installation Execution

Sunday Evening Preparation

Sunday evening preparation (9pm–11pm): existing rooftop curb inspected and verified compatible with new equipment (Carrier 48TC uses standard commercial curb footprint), electrical service verified adequate (existing 60 amp 208V 3-phase service adequate for new equipment), gas service verified adequate (existing 1" gas line with 2 psi service pressure adequate), and staging area set up in parking lot for crane lift operation Monday morning.

Monday Installation Day

Monday installation day timeline:

  • 7:00 AM: HVAC crew arrival, refrigerant recovery equipment setup for existing R-22 recovery per EPA Section 608 requirements
  • 7:30 AM: Existing rooftop unit refrigerant recovery completed, electrical and gas service disconnections completed
  • 8:00 AM: Crane arrival and setup in parking lot, safety barriers established
  • 8:30 AM: Existing unit lift off rooftop and placement on ground for removal
  • 9:15 AM: New Carrier Weathermaker 48TCED09 lift onto rooftop curb
  • 10:00 AM: Crane departure, HVAC crew begins connection work
  • 10:00 AM – 3:00 PM: Electrical connections, gas service reconnection with pressure testing, refrigerant circuit sealed unit verification, control connections
  • 3:00 PM – 5:00 PM: Initial startup and commissioning verification
  • 5:00 PM – 7:00 PM: Extended operation testing, cleanup, and final documentation

Rooftop Curb Compatibility

Rooftop curb compatibility was successful due to Carrier 48TC using standard commercial curb footprint matching Trane Voyager curb dimensions. Some replacement scenarios require curb adapter installation adding 4–6 hours to installation timeline; this project avoided that scope through equipment selection compatible with existing curb.

Commissioning Verification

Combustion Analysis

Combustion analyzer verification at both low-fire and high-fire operation:

  • High-fire operation: CO 52 ppm, stack 285°F, O2 6.8%, combustion efficiency 81.4%
  • Low-fire operation: CO 38 ppm, stack 235°F, O2 7.4%, combustion efficiency 80.8%
  • Gas manifold pressure: 3.5" WC verified

Cooling System Verification

Cooling system verification at 82°F outdoor ambient during afternoon commissioning:

  • Refrigerant charge: Sealed factory charge verified adequate
  • Compressor stages: Both stages verified operational, staged operation with programmed timeout
  • Supply air temperature: 54°F at rooftop unit supply plenum
  • Return air temperature: 76°F at rooftop unit return
  • Temperature differential: 22°F (proper range for cooling operation)
  • Static pressure: 0.62" WC total external (within Carrier 0.80" WC maximum specification for commercial RTU)

Economizer Verification

Integrated economizer verification: outdoor air damper actuation verified through full range, mixed air temperature sensor calibration verified, economizer control setpoint programmed for 65°F outdoor changeover, economizer will provide free cooling during appropriate outdoor conditions reducing compressor operation and improving overall efficiency.

Business Owner Outcome

Business Continuity Success

Business continuity achieved as planned: restaurant reopened for normal Tuesday operations with new HVAC system fully commissioned, no lost revenue beyond regular Monday closure, and customer-facing operation not affected by replacement scope.

Operating Cost Improvement

Operating cost improvement expected across full annual cycle:

  • Cooling operation: IEER 14.5 vs prior equivalent 10–11 baseline represents 30–32% cooling efficiency improvement, most significant during high summer conditions when restaurant operates cooling continuously
  • Heating operation: 82% thermal efficiency two-stage vs prior 80% single-stage single-stage represents modest efficiency improvement, more significant benefit from two-stage modulation matching load during mild heating conditions
  • Ventilation: VFD blower operation and economizer function provide efficiency benefits over prior fixed-speed blower without economizer
  • Annual estimated savings: $2,400–$3,600 in combined gas and electric consumption for restaurant operation

Commercial Maintenance Contract

Business owner enrolled in Commercial Maintenance Contract at $980/year: quarterly service visits (versus twice-yearly Comfort Club for residential), pre-season heating and cooling verification, filter service (commercial filters replaced more frequently given restaurant kitchen contamination), belt inspection and adjustment, economizer operation verification, drain pan and drain line service, and priority emergency response for restaurant business continuity considerations.

Frequently Asked Questions

How do you minimize business disruption during commercial RTU replacement?
Business disruption minimization requires careful planning: (1) closure day coordination scheduling installation during business’s regular closure day (Monday for this restaurant) or extended closure windows; (2) crane lift coordination for morning window when equipment supplier and crane service can align with business schedule; (3) equipment pre-staging for immediate installation on removal of existing unit; (4) technician team sizing for full-day installation capacity rather than multi-day installation stretching business impact; (5) temporary conditioning deployment (portable spot coolers for kitchen safety during summer installations, temporary heat for winter installations) as needed; (6) building electrical, gas, and control service verification during pre-installation phase avoiding installation-day surprises; and (7) commissioning verification before crew departure ensuring system operational for business reopening. This restaurant reopened Tuesday for normal operations with no customer-facing service disruption beyond regular Monday closure.
What’s the difference between commercial RTU and residential split-system HVAC?
Commercial packaged rooftop unit (RTU) differs from residential split-system in several ways: (1) packaged configuration integrates compressor, condenser, and evaporator/blower in single outdoor unit with rooftop installation, vs residential split-system with separate indoor and outdoor components; (2) higher capacity typical (3-25 tons for commercial RTU vs 1.5-5 tons for residential); (3) commercial ventilation requirements per ASHRAE 62.1 (typically higher outdoor air percentages than residential ASHRAE 62.2); (4) commercial control complexity with economizer, staged compressor operation, VFD blower control, and building management system integration; (5) commercial curb installation on flat roof vs residential concrete slab or pad installation; (6) commercial gas/electric packaged configuration common (heating and cooling in single unit) vs residential separate furnace and AC; (7) commercial refrigerant R-410A modern refrigerant (older units may still use R-22 with phase-out considerations); and (8) commercial maintenance requirements more frequent than residential given continuous business operation.
How was the R-22 refrigerant handled from the old unit?
R-22 refrigerant recovery from existing unit per EPA Section 608 requirements: (1) certified technician using approved recovery equipment (Marcus Wentworth EPA Section 608 Universal certified); (2) refrigerant recovered into approved recovery cylinder for recycling or disposal per EPA regulations; (3) recovery documentation maintained for regulatory compliance including refrigerant quantity, recovery date, technician certification number, and disposal method; and (4) new equipment uses R-410A modern refrigerant not affected by R-22 phase-out. R-22 refrigerant phase-out from 2020 substantially increased cost of continued service scenarios on R-22 equipment — recovered R-22 is the only supply source for continued service, and recovered R-22 typically prices at $150–$300 per pound vs new refrigerant historical pricing under $10 per pound. This makes replacement of aging R-22 equipment more economically justified even before other equipment condition considerations.
How do commercial cooling efficiency ratings work?
Commercial cooling equipment uses different efficiency ratings than residential: (1) IEER (Integrated Energy Efficiency Ratio) measures cooling efficiency across weighted operating conditions including part-load operation, higher IEER indicates better efficiency; (2) commercial RTUs also often list EER (Energy Efficiency Ratio) at 95°F outdoor rating point providing single-condition benchmark; (3) IEER is generally more representative of real-world commercial operation than EER because commercial equipment typically operates at part-load conditions most of the year; (4) new Carrier 48TCED09 IEER 14.5 provides 30–32% cooling efficiency improvement over prior 2003 Trane Voyager IEER 10–11 equivalent; (5) Rocky Mountain Power Wattsmart commercial rebate program provides incentive dollars for high-efficiency commercial cooling equipment. Commercial efficiency improvements translate to meaningful operating cost savings for restaurant continuous cooling operation during 6+ month cooling season at Bluffdale/Riverton climate.
What ongoing service does commercial RTU require?
Commercial RTU ongoing service scope is more intensive than residential given continuous business operation and commercial equipment complexity: (1) quarterly service visits (spring, summer, fall, winter) versus twice-yearly residential Comfort Club; (2) filter service more frequent given restaurant kitchen contamination (monthly filter changes typical rather than 3-6 months residential); (3) belt inspection and adjustment (commercial RTU typically uses belt-drive blower vs residential direct-drive); (4) economizer operation verification (damper actuation, sensor calibration, changeover setpoint); (5) drain pan and drain line service (commercial units produce more condensate given higher ventilation rates); (6) compressor and refrigerant system verification (subcooling and superheat readings, refrigerant charge verification); (7) combustion analyzer verification of gas heating operation across low-fire and high-fire; (8) electrical connection torque verification; (9) building management system integration verification if applicable; and (10) priority emergency response coordination for business continuity considerations. Commercial Maintenance Contract at $980/year covers quarterly service visits with priority emergency response.

Contact Bluffdale Heating & Air Conditioning

Commercial packaged rooftop unit (RTU) replacement and service, business continuity coordination minimizing customer-facing service disruption during replacement, crane lift coordination with supplier and lift service for rooftop equipment placement, temporary spot cooler deployment for kitchen safety during summer installations, Carrier Weathermaker commercial packaged gas/electric RTU installation with two-stage compressor and VFD blower operation, integrated economizer for free cooling during appropriate outdoor conditions, R-22 refrigerant recovery per EPA Section 608 requirements from replaced equipment, commercial ASHRAE 62.1 ventilation requirements coordination, Rocky Mountain Power Wattsmart commercial cooling rebate coordination, quarterly Commercial Maintenance Contract with priority emergency response, and 24/7 emergency response all route through our office at 14659 S 855 W in Bluffdale serving the greater Salt Lake Valley commercial buildings including Riverton City Park area.

Contact Us →

Office Hours

  • Emergency Service: 24 hours a day, 7 days a week
  • Office Staff: Monday – Saturday, 9:00 AM – 5:00 PM
  • Closed: Sundays and State/Federal Holidays (emergency line always active)