This guide works through the Nevada C-21 Refrigeration & A/C credential end to end: the full classification and its seven subclassifications under NAC 624.380, the PSI trade examination of 85 scored questions in 3 hours keyed to the Uniform Mechanical Code 2018, the Contractor Management Survey that accompanies it, and the qualifying-person, monetary-limit, bond and renewal rules that frame the license. The companion program page is at Nevada C-21 Refrigeration & A/C Exam Preparation.
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The credential at a glance
| Item | Verified position |
|---|---|
| Classification | C-21 Refrigeration and Air Conditioning (NAC 624.380) — the full classification covers all seven subclassifications |
| Regulator | Nevada State Contractors Board (NSCB) — NRS Chapter 624; NAC 624 |
| Trade examination | PSI, open book — 85 scored questions · 3 hours · minimum passing score 60 of 85 |
| Contractor Management Survey | PSI, open book — 60 scored items plus 3 non-scored items · 120 minutes plus 6 minutes · passing standard 45 of 60 / 75% |
| Code layers | Tested: Uniform Mechanical Code, 2018 · Field: no statewide field-code edition exists; local jurisdictions adopt their own |
| Experience | At least 4 years inside the 15 years immediately preceding application (NRS 624.260) |
| Term | Each license expires 2 years after the date it is issued (NRS 624.283) |
| Administrator note | PassProfessor is independent and is not affiliated with the Nevada State Contractors Board |
Reading the Nevada record
Nevada facts arrive in three layers, and this guide tags them as it goes. Statute facts come from NRS Chapter 624 — experience, term, bond, the Recovery Fund. Rule facts come from NAC 624 — the classification at 624.380, fees at 624.130, the application at 624.590, examinations at 624.600, endorsement at 624.615, renewal at 624.630. Bulletin facts — counts, minutes, outlines, room rules — come from PSI’s two bulletins for this credential, both updated March 25, 2026: the “C” Classification Examinations Bulletin and the Contractor Management Examination Bulletin.
One discipline governs the whole guide. The trade examination’s passing standard is published as a count, and the guide follows the bulletin exactly: the count is the standard, stated in the bulletin’s form wherever it appears, and never rendered in any other form. The survey’s standard is published in a different form, and is likewise stated only in its own form.
The route, step by step
Step one — fix the classification and the monetary limit sought. The applicant chooses C-21, full or by subclassification, and the monetary limit its financial record can support; both choices shape everything downstream.
Step two — assemble the application package. A separate application for the classification under NAC 624.590, experience documented as the next sections describe, a financial statement under NAC 624.593, fingerprint cards and background authorisation, and the Board’s application fee.
Step three — establish eligibility. The Board, not PSI, determines eligibility. The qualifying person must then pass both examinations within 6 months after the filing of the application, and an application not completed within 6 months is deemed withdrawn.
Step four — sit both examinations. The trade examination and the Contractor Management Survey, each open book, each under its own standard, with the PSI fees and room rules set out below.
Step five — qualify, bond and issue. The bond or cash deposit is in place before issuance, the license issues at the Board’s fee, and the two-year term begins.
The full scope in depth
The bulletin quotes the classification in three strands, and each strand has an edge worth learning. The refrigeration strand reaches devices, machinery and units controlling air temperatures below 50°F in refrigerators, refrigerated rooms and insulated spaces. Its connection grants are drawn tightly: natural-gas lines run from the unit to the existing gas line at or after the meter, and electrical service runs from the unit’s overcurrent device to the main panel — and the scope says expressly that other gas or electric services are not included. A candidate who reads those grants as general gas or electrical authority has over-read them. The air-conditioning strand covers equipment, devices, machinery, units and related ductwork using evaporation, refrigeration, boilers or combustion to control air temperatures in occupied structures, across installation, repair, service and maintenance. The sheet-metal and repair strand covers sheet metal work in its enumerated forms — cornices, flashings, gutters, leaders, downspouts, pans, kitchen equipment, ducts, louvers, patented chimneys, metal flues — and repair and replacement of parts of existing units and systems.
The seven subclassifications at NAC 624.380 divide that whole, and two carry internal limits worth learning. C-21d Maintenance reaches repair and replacement of parts — compressors, motors, relays, coils, heat exchangers — but stops before complete condenser assemblies on remote systems, air handlers, and any work altering a system’s design. C-21c Sheet Metal reaches fabrication and installation including metal roof systems, but not equipment using refrigeration as an integral part. The remaining five — C-21a Refrigeration, C-21b Air-Conditioning, C-21e Solar Air-Conditioning (collectors, piping and storage converting solar energy to temperature-control energy), C-21f Chilled and Hot Water Systems (boilers, chillers, coils, cooling towers, piping, pumps, storage tanks and valves producing and transferring water for temperature control), and C-21g Industrial Piping — complete the roster. A full C-21 license authorises all of it. This guide builds the full classification’s examination; it does not build subclassification sittings, and nothing here should be read as preparation tailored to one.
The trade outline in full
Eighty-five scored questions in twenty-three areas. Grouped as the trade itself groups, they read as follows.
Fuel and fire — the centre of gravity. Fuel Systems carries 10, the largest single block in the sitting, supported by Chimneys, Flues and Vents 5, Combustion Air 2, and Furnaces and Heaters 4. Together that cluster is the largest territory on the paper, and it is anchored in the room by NFPA 54 (2012) alongside the mechanical code. Candidates whose preparation is refrigeration-first should note where the weight actually sits.
Refrigeration and air side. Refrigerants and Refrigeration 7, A/C and Heat Pump Equipment 4, Evaporative Cooling 2, Chillers 3, Solar 4, and Heating and Cooling Principles 3. The solar block — 4 questions in a classification whose solar subclassification is one of seven — is easy to under-prepare and is examined from the solar manual on the reference list.
Air distribution and balance. Ducts 6, Testing, Adjusting and Balancing 3, Ventilation and Exhausts 3, Hangers and Supports 3, Insulation 1, and Sound, Vibration and Seismic Control 1. The SMACNA duct standards on the reference list serve this group directly.
Loads, controls and the machine room. Load Calculations 6 (served by Manual N), Controls 5, Piping 6, Hydronics 2, and Machine Room 1.
Safety — 4. The closing block, examined from the allowed references. Candidates should note again that OSHA 29 CFR Part 1926 is not among them for this sitting.
Around the scored 85, the bulletin layer adds that non-scored experimental items, between one and ten, may be added and count against the 3 hours. They are not identified in the room and are never part of the scored count; pacing plans should assume their presence.
The Contractor Management Survey in depth
The CMS is a business-and-law sitting in Nevada’s own form — not a NASCLA sitting, because no NASCLA edition exists for Nevada, and its only allowed reference is PSI’s Construction Business and Law Manual for Nevada. It carries 60 scored items plus 3 non-scored items in 120 minutes plus 6 minutes for the non-scored items, open book. Its outline: Licensing 10; Estimating and Bidding 7; Lien Law 3; Financial Management 12; Tax Laws 5; Labor Laws 5; Project Management 3; Contracts 6; Risk Management 4; Environmental and Safety 5. Financial Management is its largest block, and Licensing its second — the survey examines the business of contracting as Nevada regulates it, with lien law present but small. Its passing standard, in the form the bulletin publishes for this portion, is 45 of 60 / 75%. A Spanish-language version of the CMS exists; Spanish-language versions also exist for one subclassification sitting, but not for the full C-21 trade examination.
Administration for both sittings: testing at Las Vegas, Reno and Elko and at PSI centres nationwide; arrive 30 minutes early; one form of photo identification; scores reported immediately, with a diagnostic report by subject area on failure; cancellation or rescheduling without forfeiture on notice 2 days before the appointment, with voicemail not an acceptable cancellation; references highlighted, underlined and indexed beforehand but never written in, permanent tabs only; a silent, non-printing, non-programmable calculator allowed.
The code position in depth
State the Nevada position in its two halves and never let them touch. Examination half: code questions key the Uniform Mechanical Code, 2018, only — the bulletin allows that edition into the centre and bases code answers on it. Field half: Nevada has no statewide field-code edition for this trade. Nothing in the statute or rules read for this guide adopts one; local jurisdictions adopt their own editions. It follows that field experience under a locally adopted edition — even a later UMC edition — does not settle examination answers, and examination preparation does not settle field compliance. The candidate’s discipline is to hold the exam key at UMC 2018 while working, in the field, under whatever the jurisdiction of the work has adopted.
The trade reference list, complete as published, is: Uniform Mechanical Code, 2018; NFPA 54 National Fuel Gas Code, 2012; Modern Refrigeration and Air Conditioning, 19th or 20th edition; HVAC Duct Construction Standards, Metal and Flexible, 2005 (SMACNA); Manual N Commercial Load Calculation, 5th edition, 2008 (ACCA); Solar Water and Pool Heating Design and Installation Manual, 1997 (Florida Solar Energy Center); and Evaporative Air Conditioning Handbook, 3rd edition, 1997 (Watt & Brown). Material keyed to a different code family’s book is not Nevada trade material for this sitting.
Eligibility in depth
Experience. NRS 624.260(6) requires, within the 15 years immediately preceding the filing of the application, at least 4 years of experience as a journeyman, foreman, supervising employee or contractor in the specific classification applied for. A journeyman, at subsection (8), is a person fully qualified to perform the work without supervision, or who has completed a State Apprenticeship Council-approved apprenticeship program (or Board-accepted equivalent) for the classification. Training in an accredited college or university program, or a Board-accepted equivalent, may satisfy not more than 3 years of the requirement. An applicant who previously qualified in the same classification need not have accrued the experience inside the 15 years (subsection (7)). Older summaries carrying a shorter window are stale; the statute’s 15-year window governs.
The qualifying person. The qualifier must be a bona fide member or employee of the applicant, make the technical and administrative decisions, hold authority to hire, superintend, promote, transfer, lay off, discipline and discharge, and devote himself or herself solely to the business. One natural person may not qualify for more than one active license unless an ownership exception in the rule, or the public-benefit-corporation limb, applies. Qualification runs by a natural person personally or through a responsible managing employee, and for a firm through a responsible managing officer or member. On the qualifier ceasing to be connected with the licensee (NRS 624.285): written notice to the Board within 10 days; the license remains in force for a Board-set period not exceeding 30 days; failure to notify brings automatic suspension.
Financial showing. Experience is documented by four or more certificates of work experience on the Board’s form, or by a current governmental master certification in a substantially similar discipline, or proof of transferable military experience or training, or training-credit documentation. The financial statement follows the tiers at NAC 624.593 by the limit requested: at or below $25,000, a CPA-prepared statement, a Board form with affidavit, or accounting-software output with affidavit; above $25,000 and below $500,000, a CPA compilation within 6 months or a review or audit within 1 year; at or above $500,000 and below $1,000,000, a CPA compilation with full disclosures within 6 months or a review or audit within 1 year; at or above $1,000,000, a CPA review or audit within 1 year. Financial responsibility under NRS 624.262 and 624.263 is judged on solvency — net worth, liquid assets, working capital, current ratio, bonding and payment records, experience, lawsuits, liens and judgments, convictions, prior discipline, insolvency proceedings, references, and reputation for honesty and integrity — determined independently of the assets of owners, officers and qualifiers, though those may be considered. Fingerprint cards accompany the application, with a cashier’s check payable to the Nevada Highway Patrol equal to the Central Repository and FBI charges, for which the rule sets no fixed dollar amount.
Endorsement. Under NAC 624.600 and 624.615, examination waiver is available where the qualifier passed an endorsing-state examination approved by the Board, or a NASCLA-accredited examination the Board determines substantially equivalent, with verification, alongside a discretionary Board waiver for experience and qualifications. The Board determines substantial equivalence and maintains and publishes the endorsing-state list. On the Board’s current requirements, endorsement expects the trade qualifier to have been actively licensed in the endorsing state for the past 4 years with no disciplinary actions, suspension or sanctions, a verification of licensure completed by that state, and a Nevada trade examination where the endorsing state offers no equivalent trade examination. The endorsement route also waives the experience-documentation requirement where the qualifier has at least 4 years of Board-approved experience in good standing with no discipline history (NAC 624.590(3)). This guide names no endorsing states: the Board’s published list is the only reliable source.
The monetary limit in depth
The monetary limit is Nevada’s distinctive control, and it operates before, during and after the work. It is the maximum contract value the licensee may undertake on one or more construction contracts on a single construction site or subdivision site for a single client, fixed by the Board on the NRS 624.260 to 624.265 factors. The license number and the monetary limit must appear in all bids and contracts, and a bid or contract outside the license’s scope or above its limit is void (NAC 624.640). A single-project increase must be requested at least 5 working days before the bid date and approved before bidding, with not more than five single-project increase applications in any 12-month period (NAC 624.670). The licensee displays its name and license number on each commercial motor vehicle in letters and numbers approximately 1½ inches high (NRS 624.288).
The de-minimis edge cuts the other way. Nevada excepts certain small work in a classification the contractor is not licensed in — worth less than $1,000 including labour and materials, with no permit required — but the exception at NRS 624.220(4)(b) never applies to plumbing, electrical, refrigeration or air-conditioning work. For this trade, the license is the entry condition at every job size.
Fees, bond and the Recovery Fund in depth
PSI fees (vendor layer). One examination portion $95; two portions $140, only where the second examination is the CMS — two trade examinations are $95 each. Fees are non-refundable, non-transferable, and expire with the candidate’s eligibility.
Board fees (rule layer, NAC 624.130, complete schedule as sourced). Application for a classification not yet held $300; issue or renew a license $600; late filing of an active-license renewal application $150; issue or renew an inactive license $300, with an inactive late fee of $75; cash-deposit administrative fee $200; duplicate license $25; duplicate identification card $10; duplicate certificate of eligibility $50; name-change application $250; conversion application $300; single-project monetary-limit increase $75; permanent monetary-limit increase or decrease $250; change of qualified person $250; broaden-license request $250; certificate of eligibility, issue $500 and renew $300; returned checks $25. Each is its own instrument; none merges into a licensure total.
Bond (licensure instrument). A surety bond — surety authorised in Nevada, its long-term debt rated “A” or better — or a cash deposit in lieu, required before issuance, with evidence of force required at renewal. The Board fixes the amount on financial and professional responsibility and the magnitude of operations, between $1,000 and $500,000. The bond is continuous in form and the surety’s aggregate liability is capped at its face amount; the Board may increase or reduce the amount at renewal or after hearing. A cash deposit may be withdrawn 2 years after license termination or completion of authorised work, whichever is later, if no claim is outstanding. After 5 consecutive years licensed, the Board may relieve the bond requirement, and may reimpose it, including where three substantiated wage claims are filed within a 2-year period. The bond runs for owners, employees, suppliers and persons injured by unlawful acts; an action on it must be brought within 2 years of the act, and employee labour claims are preferred. A surety may cancel on 60 days’ notice by certified mail, and the license is suspended or revoked unless an equivalent bond or deposit is furnished.
Recovery Fund (residential layer only, NRS 624.470 and following). A residential contractor pays a biennial assessment by monetary limit: $200 at a limit of not more than $1,000,000; $500 above that where the limit is limited; $1,000 for an unlimited license — stated as statutory caps. An individual recovery is capped at $40,000, and claims against a single contractor are subject to a statutory aggregate cap. An injured person files a complaint within 4 years after completion of the qualified services and a judgment-satisfaction application within 2 years after judgment. Residential contractors must give owners the statutory Recovery Fund notice in the contract, on pain of a Board fine of not more than $250 for a first violation and not more than $500 for a later one. These figures govern the residential layer only.
Renewal and retakes in depth
The license expires 2 years after issuance (NRS 624.283), with the Board able to stagger biennial renewals. Under NAC 624.630 the Board mails the renewal application; the completed application is due not later than the last day of the month in which the license expires, and where a financial statement was requested, the application, fee and statement are due by the first day of that month. The late fee is $150 for an active license. A license not renewed on or before its renewal date is automatically suspended; reinstatement is available within 6 months on a renewal application, the renewal fee and a Board-fixed reinstatement fee, if otherwise in good standing with no complaints pending — otherwise a current CPA financial statement or other conditions may be required. Beyond 6 months the license may be cancelled, and a license then issues only on an original application. Timely but incomplete renewals are conditionally renewed. Inactive status renews on the same cycle, and an inactive license not placed on active status within 8 years expires (NAC 624.635). Military-service reinstatement exceptions exist at NRS 624.283. Changes in address or personnel affecting the application must be reported in writing within 30 days. And the renewal record carries no coursework: neither the statute nor the renewal rule imposes any continuing-education requirement for this license.
Retakes, in their two unmerged layers: at PSI, a candidate who fails waits 2 weeks before retaking each portion; at the rule layer (NAC 624.600), failing a third time voids the application, and the candidate re-applies directly with the Board, with a fresh application and fee, 30 days or more after the date of the last examination.
A study plan built on the two sittings
First, fuel systems and the code together. The largest trade block and its supporting venting and combustion areas are reference-driven; study them inside UMC 2018 and NFPA 54, retrieving under time. Second, the breadth sweep. Twenty-three areas punish narrow preparation; work the outline in mixed sets so no small block — insulation, machine room, seismic control — is met for the first time in the room. Third, the charts-and-manual skills. Load calculations from Manual N and refrigeration reasoning from the allowed texts are performances; drill them timed. Fourth, the CMS as its own sitting. Its Financial Management and Licensing weight, its single allowed reference, and its business content reward separate, scheduled preparation rather than leftover time. Fifth, the Nevada layer as memorised structure. The count-form standard, the 15-year window, the monetary-limit rules, the fee layers and the two-layer retake rule are short, exact material — learn them verbatim.
The errors this credential is built to catch
Restating the trade standard in another form. The bulletin publishes a count; any other rendering is an error. Assuming a statewide field code. None exists; the examination layer stands alone at UMC 2018. Bringing the wrong shelf. OSHA Part 1926 is not allowed for the trade sitting, and the CMS allows exactly one reference — the Nevada manual, not any NASCLA edition. Reading the connection grants broadly. Gas and electrical authority inside C-21 stop at the meter-side connection and the overcurrent-device run described in the scope. Expecting a small-job exception. For refrigeration and air-conditioning work, there is none. Merging the fee layers, or the retake layers. PSI’s charges, the Board’s schedule and the bond are separate instruments, as are the 2-week wait and the third-failure rule. Letting the 6-month clocks lapse — completion of the application, and passing both examinations after filing.
Frequently asked questions
How do the program page and this guide divide the work?
The program page states the verified position compactly. This guide works through the same record in depth — scope edges, both outlines, the financial showing, the bond’s full terms and the renewal choreography. Both describe the same program: Nevada C-21 Refrigeration & A/C Exam Preparation.
Why is the trade passing standard always written as a count?
Because the PSI bulletin publishes it as a count: a minimum passing score of 60 of 85. This package follows the bulletin and states the standard in that form only.
Does the full C-21 examination cover every subclassification?
The full classification license authorises all seven subclassifications, and this program prepares candidates for the full C-21 examination. It does not promise preparation tailored to any individual subclassification sitting.
What references may be taken into the trade examination?
UMC 2018; NFPA 54 (2012); Modern Refrigeration and Air Conditioning (19th or 20th edition); SMACNA HVAC Duct Construction Standards (2005); ACCA Manual N (5th edition, 2008); the Solar Water and Pool Heating Design and Installation Manual (1997); and the Evaporative Air Conditioning Handbook (3rd edition, 1997). OSHA Part 1926 is not allowed.
What happens after a failure?
Scores are reported immediately with a diagnostic report by subject area. At the PSI layer the wait before retaking a portion is 2 weeks; at the rule layer, a third failure voids the application, and re-application may follow 30 days or more after the last examination.
Can licensure from another state shorten the route?
Possibly, through the Board’s endorsement mechanism — an approved endorsing-state examination or a substantially equivalent NASCLA-accredited examination, with verification, and a possible waiver of the experience-documentation requirement under NAC 624.590(3). This guide names no endorsing states.
Is there a hands-on component to either examination?
The sources behind this guide describe the PSI sittings recorded here and state no hands-on component; this guide states neither its presence nor a verified absence.
Do fingerprints carry a set fee?
No fixed dollar amount exists in the rule. The fingerprint cards are accompanied by a cashier’s check payable to the Nevada Highway Patrol equal to the Central Repository and FBI charges.
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