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We take pride in being recognized as one of Hawaii’s Top 250 businesses. With over 70 years of serving Hawaii, we remain committed to delivering quality products and services. This commitment to high standards allows us to create an ideal environment for continuous learning and development. Our employees have the added benefit of working alongside industry leaders who provide valuable insight into our industry and teach through professional mentorship.


Benefits offered to our valued employees include paid medical insurance, 401(k) retirement plan, paid time off, holidays, group life insurance, flexible spending accounts, and supplemental insurance.


It's simple. Complete our employee application and email it with your resume to hr@senplex.com

Sen Plex Corporation and its subsidiaries, Oahu Plumbing & Sheet Metal, Ltd, Oahu Air Conditioning Company and Oahu Air Conditioning Service, Inc. are equal opportunity and affirmative action employers. Reasonable accommodations may be made to enable qualified individuals with disabilities to perform the essential functions.

Available Positions

Accounts Payable Clerk

Duties and Responsibilities:

• Review invoices and properly allocate expenses to the correct cost account and/or job and cost center

• Verify vendor statements and maintain vendor files

• Resolve discrepancies with vendors and follow up as needed

• Process payments on a timely basis

• Reconcile credit card statements

• Work closely with the various departments to obtain missing information

• Communicate effectively with customers, vendors and colleagues

• Perform additional duties as assigned

Desired Qualifications:

• Associates degree in Accounting

• 1 year of AP experience

• Experience with Timberline and construction industry accounting is a plus

• Proficiency in Microsoft Office: Word, Excel, Outlook

• Excellent written and verbal communication

Accounts Receivable Specialist

Duties and Responsibilities:

• Enter daily cash received in the accounting system

• Follow up with customers for delinquent payments

• Responsible for collecting money on COD accounts in a timely manner

• Process credit card payments

• Assist the billing department with preparing and issuing invoices to customers

• Investigate overpayments and process refunds and/or credit memos

• Print and distribute monthly customer statements

• Update detail aging report with daily deposits

• Process credit application and run credit checks to ensure credit worthiness

• Setup / update customer information in accounts receivables

• Provide month end closing reports as they pertain to accounts receivable

• Other duties as assigned

Desired Qualifications:

• Associates degree in Accounting

• 1 year of collection experience

• Accuracy and attention to detail

• Proficiency in Microsoft Office: Word, Excel, Outlook

• Excellent written and verbal communication

• Positive, courteous and professional attitude in dealing with internal and external customers

• Strong time management and organizational skills

• Ability to work in a fast-paced environment and meet deadlines while maintaining a professional demeanor

• Ability to portray a positive phone and email image

• Strong team player who is dependable, reliable, detail-oriented with good attendance

• Conscientious about timeliness of assignments and quality of work

• Must reside on Oahu and be eligible to work in the United States

Apprentice - Maui

Duties and Responsibilities:

• Conduct regular maintenance service on air conditioning systems

• Peform light repairs to existing customer equipment

• Inspect equipment and determine what work is needed to repair the equipment

• Provide customer with an estimated repair cost

• Order parts and schedule the repair service

• Coordinate tasks and jobs efficiently, follow through on customer questions

• Follow all established policies, procedures and direction from the supervisor

• Maintain a pleasant and courteous demeanor

• Follow safe work practices at all times

Desired Qualifications:

• High school diploma or equivalent

• Technical school education in related field desired

• Working knowledge of air conditioning systems, components, controls and system operations

• Basic knowledge of air conditioning equipment and duct cleaning highly desirable

• Good time management, analytical and communication skills

• Ability to maintain composure at all times, especially in difficult situations

• Detail-oriented and able to manage multiple concurrent projects and requests

• Valid driver’s license, clean drivers abstract and ability to drive service van required

• Must be eligible to work in the United States

Billing Clerk

Duties and Responsibilities:

• Accurately prepare billing and credit memos with the proper supporting documentation

• Process credit card payments

• Calculate payment amount on COD invoices

• Follow up on collection for all COD accounts

• Preparation and reconciliation of master billings to individual invoices

• Coordinate with concerned parties to gather information needed for billing

• Verify cost to ensure accurate pricing

• Investigate and resolve discrepancies

• Mail and/or upload invoices to customers

• Update billing notes as necessary

• Respond to customer queries related to invoices sent

• Generate month-end closing reports in a timely manner

• Other duties assigned

Desired Qualifications:

• Associate degree in accounting is preferred

• 3+ years of billing experience

• Proficiency in Microsoft Office products

• Excellent written and verbal communication skills

• Must reside on Oahu and be eligible to work in the United States

Contract Administrator

Duties and Responsibilities:

• Review awarded contracts, identify contract obligations such as certified payroll, reporting, insurance, bonds etc.

• Provide administrative assistance to Project Managers and Estimators

• Setup and manage contracts and Service Maintenance Agreements, and Work orders

• Prepare change orders, purchase orders, subcontracts, and job cost transmittals

• Maintain accurate records by updating electronic files and/or software to monitor and record project documents

• Prepare project information, reports and filings required to close the job

• Download Certificate of Vendor Compliance

• Compile, distribute and file customer contract packets

• Assist in collection efforts as needed and inform billing department of the necessary billing adjustments

• Assist estimators as needed in preparation of bid packages

• Assist in other areas as needed

Desired Qualifications:

• Associate Degree

• 3+ years of construction or service contract administration experience preferred

• Construction accounting or billing experience is a plus

• Excellent time management skills, proven ability to meet all required deadlines while handling multiple priorities

• Excellent verbal and written communication skills, exhibiting a professional demeanor at all times

• Strong computer skills and aptitude to learn various computer programs

• Must reside on Oahu and be eligible to work in the United States


Duties and Responsibilities:

• Responsible for managing the accounting department including initiating new processes and procedures aimed at creating efficiency

• Oversee all aspects of accounts payables, accounts receivables, and closely monitor cash functions

• Ensure payroll is accurately processed and all related reporting and compliance requirements are met

• Ensure proper job cost reporting of transactions, prepare quarterly job closing and related journal entries

• Prepare and analyze Work-In-Process reports

• Perform month-end closing, including analysis of operation costs and results

• Issue monthly financial statements, perform analytical review to ensure accurate accounting records are maintained

• Prepare quarterly reports for financial institutions and Board of Directors

• Prepare annual budget

• Coordinate annual review by independent auditors

• Ensure compliance with all applicable laws, rules, and regulations

• Performs special projects and completes all other duties as assigned

Desired Qualifications:

• Bachelor’s Degree in Accounting or Finance

• 8 - 10+ years of complex, progressive accounting experience, including construction accounting

• Solid GAAP and financial reporting technical skills

• Exceptional work ethic, strong time management skills with the ability to meet deadlines

• Advanced decision making, analytical and problem-solving abilities

• Knowledge of Timberline software desirable

• Strong communication skills at all levels of the organization and a desire to manage personnel

• Demonstrated knowledge with Microsoft Office products – highly skilled in Excel including spreadsheets, pivot table and other key excel functions

Project Manager

Duties and Responsibilities:

• Acts as the primary contact for the general contractor and/or owner; lead and/or attend

• Acts as the primary contact for the general contractor and/or owner; lead and/or attend project meetings, maintain communication regarding all project related matters

• Review Contracts, Project Plans and Specifications

• Prepare subcontract agreements, purchase orders, schedule of values and customer billings

• Review submittals and shop drawings for accuracy, efficiency, and clarity

• Responsible for the purchasing, scheduling and delivery of equipment and materials required for the project, ensure accuracy to project plans and specifications

• Prepare and submit change order estimates and work orders, confirm completion of changes

• Identify and recommend appropriate cost savings/value engineering items

• Work with general contractor and/or owner, subcontractors, vendors and various internal departments and field throughout the negotiation process, provide clarification and resolution as needed

• Prepare work order and budget for any change order work

• Monitor job cost and update budget constantly

• Identify, analyze and resolve problems through RFI process, define any cost or schedule impact

• Mentor and train junior engineers

• Provide project schedule and updates to the appropriate departments

• Prepare and submit closing documents, maintain all project documentation diligently

Desired Qualifications:

• Bachelor’s Degree in engineering, Mechanical Engineering preferred

• 8+ years of experience in HVAC trade

• Project management experience

• Solid understanding of Trade Standards and Practices, building codes and standards

• Ability to read and understand specifications and plans

• Good understanding of the cost estimating including labor units used for estimating and material costing

• Perform complex tasks and handle multiple priorities while maintaining a professional demeanor at all times

• Excellent time management skills, proven ability to meet all required deadlines

• Excellent verbal and written communication skills

• Strong computer skills and ability to quickly learn various computer programs

• Drivers License with a clean traffic abstract

Service Estimator

Duties and Responsibilities:

• Understand trade standards and practices, building codes and standards

• Read and understand specifications, architectural and mechanical plans

• Understand the bid process including labor and material costing

• Manage entire life cycle of assigned projects, taking ownership of all communication, contract agreements, budgets, and closing documentation

• Develop and maintain client relationships to achieve cooperation and establish partnerships

• Promptly address any issues and find satisfactory solutions

Desired Qualifications:

• Bachelor’s in Mechanical, Electrical, or Civil Engineering, or other industry related field

• 1-2 years of HVAC experience in lieu of education

• Ability to work independently, collecting and processing data and information, formulating conclusions and making recommendations

• Conscientious about timeliness of assignments and quality of work product

• Possess exceptional written and verbal communication skills, including ability to effectively interact with operation personnel and management

• Strong organizational skills to manage multiple assignments effectively and efficiently

• Must reside on Oahu and be eligible to work in the United States

• Drivers License with a clean traffic abstract

Warehouse Worker

Duties and Responsibilities:

• Responsible for receiving incoming inventory, materials and parts (occasional manual offload)

• Check all received freight for damage and count according to company procedures; report damage, shortages, overages, and other discrepencies on the outgoing manifest or to supervisor

• Responsible for outgoing shipments; pre-load and deliver materials, parts or equipment to various jobsites or prepare for shipping to the neighbor islands

• Pick-up will calls from various vendors for all departments

• Operate forklift to move parts, equipment, supplies, etc.

• Clean and maintain warehouse and yard area

• Provide support tall departments in relocation, removal of office supplies, equipment, etc.

• Assist field and shop as needed

Desired Qualifications:

• High school diploma

• Warehouse experience

• Experience driving a forklift

• CDL (Commercial Driver's License) highly desirable

• Must have a valid Driver’s License with a clean Traffic Abstract

• Dependable, honest and able to accept constructive criticism

• Have good communication skills and ability to follow instructions

• Able to lift 50 pounds, with or without assistance

• Must be available to work occasional weekends

Featured projects

OACS and OPSM are full-service mechanical companies specializing in all types of commercial heating, ventilation, air conditioning, plumbing, and sheet metal services. Here are a few of the projects we have worked on: