Commercial Rooftop Unit (RTU) Service in Salt Lake County

July 28, 2024. Salt Lake County hit 99°F on a Tuesday afternoon. A property manager named Carla Mendoza (no relation to our permit coordinator Carla Mendoza — common surname) called us about a Sandy strip mall: one of the four 5-ton Carrier WeatherMaster rooftop units serving a tenant boutique had stopped cooling around 1:30 p.m. The boutique owner was watching customers leave the increasingly warm store, calling property management every 20 minutes. Marcus Halverson was on a residential service call in Sandy and was dispatched directly to the roof. Climbing the access ladder in 99°F heat with full tool belt, refrigerant gauge set, and diagnostic equipment is one of the realities of commercial HVAC work. Diagnostic took 18 minutes on the roof: compressor contactor had welded shut, then failed open during a thermal cycle, leaving the compressor running but the condenser fan motor not energized. Compressor overheated and tripped on internal overload. Carla had authorized repair-or-replace decision in writing during her last quarterly maintenance visit, with $1,400 ceiling on emergency repairs. Marcus called from the roof: contactor + condenser fan motor + electrical inspection = $1,285. Authorized. Repair completed by 4:15 p.m. Boutique recooled by 5:30 p.m. One rooftop unit served, one tenant satisfied, one storefront didn’t lose an evening of summer business. This is the work pattern for commercial RTU service — quick diagnostic, decisive repair authorization, completion before next business cycle.

Rooftop units (RTUs) are the dominant commercial HVAC equipment category in Salt Lake County. They’re called rooftop units because they’re typically installed on commercial building roofs as a single packaged unit containing the compressor, condenser, evaporator coil, blower, electric or gas heat (depending on configuration), and controls in one cabinet. RTUs simplify commercial HVAC installation (single equipment delivery, single set of refrigerant lines vs. split systems), provide easy access for service (technician works on roof rather than inside the building), and offer good performance at reasonable cost for typical light commercial applications. We service the full range from cost-conscious tier (Goodman, Heil, Tempstar) through mid-tier (Carrier, Trane, Lennox, York) and premium variable-capacity equipment. This page covers RTU repair, maintenance, and replacement scenarios. For broader commercial context see the commercial services hub and commercial HVAC overview.

RTU Equipment We Service

Carrier WeatherMaster Series

Capacity range:

3-25 ton, with 5-15 ton most common in our service area.

Key models:

• WeatherMaster 50TC: Standard light commercial, 3-10 ton single-stage and two-stage
• WeatherMaster 50RH: Higher-efficiency tier with two-stage cooling, modulating gas heat
• WeatherMaster 50EJ/EK: Premium variable-capacity with Carrier Infinity zoning compatibility
• WeatherExpert 50WC: Premium tier with variable-speed compressors, ECM blower, highest efficiency

Common service items:

Compressor replacement (most expensive single-component repair), condenser fan motor failure, contactor failure (Carla’s case study), control board replacement, refrigerant leak repair, evaporator coil leak repair, blower motor replacement.

Carrier-specific certifications:

We’re a Carrier Factory Authorized Dealer with WeatherExpert certification. Parts availability, warranty service, and equipment-specific training all benefit from this status.

Trane Voyager Series

Capacity range:

3-25 ton, full range serving most light commercial applications.

Key models:

• Voyager I: Cost-conscious light commercial, single-stage, 3-10 ton
• Voyager II: Mid-tier with two-stage cooling and modulating gas heat
• Voyager III: Premium tier with variable-speed compressors

Trane-specific advantages:

Trane Voyager series is engineered for serviceability, with technician-friendly access panels and modular component design. Common in Salt Lake’s commercial market due to widespread adoption by major property management companies and developers.

Our credentials:

Trane Comfort Specialist with commercial training track. Direct access to Trane technical support for unusual diagnostic situations.

Lennox Strategos and Energence Series

Strategos series:

3-12 ton light commercial. Single-stage and two-stage cooling, gas or electric heat options. Mid-tier price point.

Energence series:

3-25 ton premium tier with variable-capacity options. Higher efficiency than Strategos but at premium pricing.

Common applications:

Premium retail, professional offices, restaurants with comfort priority. Less common in cost-conscious applications.

York Sunline Series

Capacity range:

3-15 ton. Single-stage and two-stage cooling.

Key positioning:

Mid-tier cost-effective option. Owned by Johnson Controls, integrated with broader York commercial product lineup.

Goodman, Heil, Tempstar (Cost-Conscious Tier)

Capacity range:

3-7.5 ton most common (limited capacity above 7.5 ton in cost-conscious tier).

Positioning:

Lowest cost commercial-grade equipment. Adequate performance for budget-constrained applications. Shorter expected service life (12-15 years vs. 15-20 years for premium tier). Common in: cost-conscious retail, multi-unit residential, properties with shorter operational horizons.

Daikin / Mitsubishi VRF (Specialized Commercial)

Not technically RTUs:

Variable Refrigerant Flow systems use a single (or multiple) outdoor units serving multiple indoor heads. Different from packaged RTUs but covered here because the outdoor units are typically rooftop-mounted.

Capacity:

Mitsubishi VRF and Daikin VRV systems range from 60,000-360,000 BTU/hr outdoor capacity, serving 8-50+ indoor heads.

Applications:

Office buildings prioritizing zonal control, hotels, retail with multiple zones, restaurants with separate dining/kitchen/bar.

Common RTU Repair Scenarios

Compressor failure:

Most expensive single-component failure. Causes: refrigerant slugging (liquid returning to compressor), electrical failure (voltage events, contactor welding), age-related wear (15+ year old equipment), internal overload from prolonged poor conditions. Repair: compressor replacement ($1,800-$3,800 parts + $385-$840 labor) or full RTU replacement (when equipment is 12+ years old).

Contactor failure (Carla’s scenario):

Common with high-cycle commercial equipment. Contactor welds closed (compressor or fan runs continuously) or fails open (equipment doesn’t start). Repair: contactor replacement $245-$485 installed.

Condenser fan motor failure:

Outdoor fan motor stops working; condenser coil temperature climbs rapidly; compressor trips on internal protection. Repair: motor replacement $485-$1,200 + labor.

Refrigerant leak:

Coil corrosion (most common with R-22 legacy equipment), brazing joint failure, valve failure, vibration-induced cracks. Repair: leak location with electronic detector, isolation and repair (brazing or coil replacement), evacuation and recharge. $640-$2,800 depending on leak location and refrigerant type.

Evaporator coil failure:

Refrigerant leak from formicary corrosion (most common with copper coils in environments with VOC exposure), vibration-induced cracks, manufacturing defects. Repair: coil replacement $1,800-$3,400 + refrigerant + labor.

Control board failure:

Component failures on printed circuit board, surge damage, corrosion. Repair: board replacement $485-$1,400 + labor.

Blower motor failure:

ECM module failure on variable-speed equipment, PSC motor failure on older equipment, capacitor failure. Repair: motor replacement $485-$1,400 + labor.

Economizer issues:

Economizer dampers stuck, sensors failed, controls disconnected. Often disabled by previous service to “make equipment work” without diagnosing actual problem. Repair: damper service, sensor replacement, control programming $385-$840.

Gas heat issues (gas RTUs):

Ignitor failure, gas valve failure, pressure switch failure, flame sensor fouling, heat exchanger cracking. Repair scope varies; gas heat repairs typically $385-$1,400 depending on component.

Drain pan corrosion / condensate leaks:

Standard maintenance item over 8-10 year service life. Repair: drain pan replacement $385-$840 + labor.

RTU Replacement Scenarios

Age-driven replacement (most common):

RTU 15+ years old with declining performance, refrigerant phase-out considerations (R-22 equipment requires replacement at this age), accumulating repair costs, declining efficiency. Mid-tier replacement typical: $11,400-$18,400 for 3-5 ton unit, $14,800-$28,400 for 5-10 ton.

Catastrophic failure replacement:

Equipment beyond economical repair. Compressor failure on 12+ year old unit. Multiple major component failures. Refrigerant system contamination. Emergency replacement scenarios — we have stocked replacement units for common 3-5 ton applications during peak demand seasons.

Tenant-driven replacement:

New tenant with different occupancy patterns requires different equipment (higher capacity for restaurant taking over retail, ASHRAE 170 compliance for medical office taking over standard office). Replacement coordinated with tenant build-out.

Energy efficiency upgrade:

Property owner replacing functional but inefficient equipment with higher-efficiency tier. Drivers: rebate availability, energy cost reduction, sustainability goals, tenant comfort improvement.

Coordinated multi-unit replacement (Carrier 50TC scenario):

Properties with multiple aging RTUs: phased replacement strategy spreading capital expenditure across years while standardizing on common equipment platform. The Gateway law firm example on the commercial HVAC page illustrates this approach.

The RTU Service Process

1. Initial diagnostic. Technician arrives on-site, typically within 2-4 hours for maintenance plan members during business hours. Roof access verification (some buildings have specific safety requirements for roof access). Symptoms confirmation from property manager or tenant.
2. Equipment inspection on roof. Diagnostic equipment carried up: refrigerant gauges, electrical testers, combustion analyzer for gas equipment, control diagnostic tools. Initial inspection 15-30 minutes for most issues.
3. Diagnostic completion. Specific failure identified. Photos taken of relevant components. Repair scope determined: in-the-truck parts vs. parts requiring procurement.
4. Customer authorization. Property manager or owner contacted with diagnosis and repair quote. Authorization obtained before proceeding. Plan members with established repair authorization ceilings (like Carla’s $1,400 ceiling) often allow immediate proceeding.
5. Repair execution. Common repairs completed on-site: contactor replacement, capacitor replacement, refrigerant adjustment, control board replacement, blower motor replacement (smaller commercial sizes). Major repairs scheduled separately: full compressor replacement, evaporator coil replacement, control system overhaul.
6. Commissioning. Equipment restored to operation. Refrigerant charge verified. Combustion analysis performed (gas equipment). Safety devices verified. Operation through full cycle confirmed.
7. Documentation. Written service report with measurements and findings. Photos of repaired components. Recommendations for any other observed issues. Delivered electronically within 24 hours.
8. Follow-up. If repair was scheduled (not immediate), parts ordered and follow-up service visit scheduled. For complete repairs, no follow-up needed; next quarterly maintenance visit catches any related concerns.

RTU Maintenance Scope

Quarterly maintenance visit scope for typical 3-10 ton RTU (more detailed for premium variable-capacity equipment, less detailed for cost-conscious tier):

Refrigerant system:

Subcooling and superheat measurement. Refrigerant level verification; adjustment if needed. Refrigerant leak detection if pressure indicates concern. EPA refrigerant tracking documentation (systems with 50+ pounds).

Outdoor section:

Condenser coil cleaning (debris removal, coil washing). Compressor amperage measurement. Compressor capacitor microfarad measurement. Condenser fan motor amperage. Contactor inspection.

Indoor section:

Evaporator coil inspection (visible portion). Blower wheel cleanliness. Blower motor amperage. Capacitor measurement (PSC equipment). ECM module diagnostic (variable-speed equipment).

Electrical:

Disconnect electrical inspection. Wiring connection tightness. Voltage measurement. Amperage measurements compared to nameplate FLA.

Gas heat (gas RTUs):

Combustion analysis with Testo 320: CO, O₂, CO₂, flue gas temperature, efficiency. Heat exchanger borescope inspection (equipment 10+ years old). Manifold pressure verification with altitude derate. Flame sensor microamp reading. Hot surface igniter resistance.

Controls and safety:

Thermostat and control board diagnostic. Pressure switch verification. Limit switch testing. Economizer function test. Outside air damper operation.

Filter and IAQ:

Filter inspection and replacement. Static pressure measurement. Drain pan inspection. Condensate drain line clearing.

Written report:

All measurements documented. Photos of any concerns. Recommendations with priority categorization (immediate, near-term, monitor).

Pricing Reference (Q2 2026)

Diagnostic visit:

$125-$245 per visit (credited toward authorized repair on first visit). Plan members: included in plan service.

Common repairs:

• Contactor replacement: $245-$485 installed
• Capacitor replacement: $185-$385 (compressor capacitor higher; blower capacitor lower)
• Compressor replacement: $2,400-$5,400 + refrigerant
• Condenser fan motor: $485-$1,200 + labor
• Blower motor replacement: $485-$1,400 + labor
• Evaporator coil replacement: $1,800-$3,400 + refrigerant + labor
• Control board replacement: $485-$1,400 + labor
• Refrigerant leak repair (depending on location): $640-$2,800
• Drain pan replacement: $385-$840 + labor
• Economizer service: $385-$840
• Heat exchanger replacement (gas equipment): $1,800-$3,400 + labor

Refrigerant replacement (when needed):

R-22 (legacy): $75-$140 per pound. R-410A: $35-$65 per pound. R-454B: $25-$45 per pound.

RTU replacement (most common):

• 3-5 ton single-stage replacement: $8,400-$13,800 per unit installed
• 3-5 ton two-stage replacement: $11,400-$18,400 per unit installed
• 5-10 ton replacement: $14,800-$28,400 per unit installed
• 10-15 ton replacement: $24,800-$48,800 per unit installed

Crane service (when needed):

For larger RTUs (over 5 tons) and roofs without crane truck access, dedicated crane service required. Typically $640-$2,400 per visit depending on lift complexity. Smaller RTUs can sometimes be hand-set with truck-mounted hoist for $245-$485.

Plan member discounts:

15-20% off all parts and labor for commercial maintenance plan members. After-hours dispatch fees waived. Priority dispatch with response time guarantees.

Tax considerations:

Section 179 deduction available for RTU replacement costs up to $1.16M annually. Bonus depreciation. Documentation provided for tax filing.

Rebates:

Rocky Mountain Power Wattsmart commercial rebates: $400-$1,200 per ton for high-efficiency equipment.

What Makes RTU Service Quality Different

Roof access expertise:

Commercial roofs require safety procedures: roof access permits, fall protection, weight limits for technician + equipment, weather considerations for roof work. Our commercial techs are trained on these procedures.

Carrier WeatherExpert certification:

Carrier Factory Authorized Dealer with WeatherExpert certification for premium commercial equipment. Provides: faster warranty service, equipment-specific training, parts availability for Carrier-specific components.

Truck-stocked common RTU parts:

Common contactors, capacitors, control boards for major platforms (Carrier, Trane, Lennox, York). Reduces multi-visit repair scenarios.

EPA refrigerant compliance:

EPA Section 608 certified technicians. Refrigerant tracking and documentation for systems with 50+ pounds. Proper recovery and recharge procedures.

Combustion analysis capability:

Testo 320 combustion analyzer with altitude derate verification. Proper combustion for gas RTUs especially important at Salt Lake’s 4,226 ft elevation.

Documentation rigor:

Commercial property owners need documentation for: AHJ inspections, insurance audits, ASHRAE compliance, tenant complaints, capital planning. We deliver photos, measurements, and written reports suitable for all these purposes.

Frequently Asked Questions

How quickly can you respond to an RTU failure?

Commercial maintenance plan members: 2-4 hour priority dispatch during business hours, 1-hour for Larger Commercial tier. After-hours: 2-4 hours from initial call. Non-plan customers: 1-2 business days typical, faster during shoulder seasons. Critical-uptime customers with custom plans: 1-hour or less response time available.

How long does an RTU last?

15-20 years for typical commercial RTUs with regular maintenance. Premium variable-capacity equipment: 18-25 years. Cost-conscious tier: 12-15 years. Commercial runtimes (12-16 hours/day) shorten service life compared to residential runtimes.

Can you replace an RTU during business hours?

Yes, for property managers who prefer that approach. Most RTU replacements can be completed in 4-8 hours, restoring HVAC to operation by end of business day. After-hours and weekend replacement also available; sometimes better for retail tenants where business hours service interruption is unacceptable.

Do you provide temporary cooling during RTU replacement?

Portable cooling units available for situations where extended outage would be problematic. Spot coolers, mobile chillers, or roof-mounted portable HVAC can maintain comfort during equipment swap-out. Typically rentable for $385-$840/day depending on capacity.

What’s the cheapest RTU replacement option?

Cost-conscious tier 3-5 ton single-stage replacement: $8,400-$13,800 installed. This is the lowest-cost adequate solution. For properties planning longer-term occupancy or with revenue-impact considerations, mid-tier ($11,400-$18,400) typically provides better value due to higher efficiency and longer service life.

Schedule RTU Service

Same-day diagnostic for maintenance plan members with priority dispatch. Non-plan customers typically 1-2 business days.

• Phone: (385) 300-1867
• Address: 756 E Winchester St #322, Salt Lake City, UT 84107
• Email: info@saltlakecityheatingairconditioning.xyz
• Utah DOPL HVAC Contractor License: #11567823-5501
• EPA Section 608 Universal (Lead Tech): #608U-2009-447129

Schedule Service →

Office Hours

• Emergency Service: 24 hours a day, 7 days a week
• Office Staff: Monday – Friday, 8:00 AM – 5:00 PM
• Closed: Weekends and State/Federal Holidays (emergency line always active)