BAS Application Engineer Position

We are seeking a detail-oriented BAS Application Engineer to support the design and execution of building automation projects. This role is responsible for developing control drawings (primarily in Microsoft Visio), interpreting project documents, and supporting project teams to ensure systems are designed correctly and installed efficiently.

You will work closely with project managers, field technicians, and contractors to keep projects on track and prevent issues before they hit the field.

Since 1954, Jarrell has been building trusted partnerships in St. Louis and nationwide. As a family-owned, full-service mechanical contractor, we provide end-to-end design-build MEP solutions, from preconstruction and engineering to installation and ongoing service. Our in-house expertise and state-of-the-art prefabrication shops give us unmatched control over quality, safety, and schedule from the start. Specializing in HVAC, plumbing, piping, refrigeration, and control systems, we deliver efficient, high-performing solutions built for long-term reliability. From data centers and manufacturing facilities to schools and multifamily housing, customers trust us for hands-on expertise, innovative thinking, and our commitment to quality, safety, and performance.

• Develop BAS control drawings using Microsoft Visio
• Interpret mechanical plans, specifications, and sequences of operation
• Produce complete submittal packages, including:
• Control wiring diagrams
• Valve and damper schedules
• BAS equipment selection
• Order materials and coordinate with vendors to ensure timely delivery for project schedules
• Design BAS solutions for new construction and retrofit projects
• Integrate and support systems utilizing Trane and Distech Controls platforms
• Coordinate with project managers, contractors, and internal teams to maintain project timelines
• Provide technical support to project managers and field installation teams
• Attend job meetings and site visits as required
• Identify and resolve design issues before they impact the field

• 3+ years of experience in:
• Building Automation Systems (BAS)
• HVAC Controls
• Industrial Automation
• Experience creating control drawings (Visio strongly preferred)
• Ability to read and interpret mechanical and electrical drawings
• Working knowledge of HVAC systems and sequences of operation

Preferred Skills & Qualifications

• Experience with Trane and/or **Distech Controls systems
• Niagara platform experience preferred (Niagara 4 a strong plus)
• Familiarity with platforms such as:
• Trane Tracer / Symbio
• Distech EC-Net (Niagara-based)
• Strong understanding of:
• RTUs, VAVs, DOAS, boilers, chillers
• Electrical systems and control wiring
• AutoCAD and/or Revit experience is a plus, but not required
• Basic understanding of networking (BACnet/MSTP, BACnet/IP, Modbus, etc.)
• Field experience (highly valued)

• Competitive salary based on experience and credentials.
• Full benefits package—health, dental, vision, life insurance, 401(k) with match, and PTO.

Who We’re Looking For

• Someone who can think through a system, not just reuse old drawings
• Strong attention to detail—bad drawings turn into expensive field problems
• Ability to manage multiple projects without losing control of deadlines
• A communicator who can work with both office staff and field technicians

Why This Role Matters

Bad control drawings create delays, change orders, and confusion in the field. Good ones keep projects moving and crews productive. This role is the difference.