916.1 General
Pool and spa heaters must be installed in accordance with the manufacturer's instructions. The IMC 2024 baseline distinguishes:
Oil-fired pool and spa heaters: tested in accordance with UL 726
Electric pool and spa heaters: tested in accordance with UL 1261
Pool and spa heat pump water heaters: comply with UL 1995, UL/CSA 60335-2-40 or CSA C22.2 No. 236
Do not assign UL 1261 to every electrically powered pool heater. Section 916 identifies heat pump water heaters separately.
Exception: portable residential spas
Portable residential spas and portable residential exercise spas must comply with UL 1563 or CSA C22.2 No. 218.1. The exception names specific equipment categories. It is not a blanket exemption for all spa heaters.
Why it matters
A generic "pool heater" schedule can hide the distinction the code makes. The selected equipment category, applicable standard and manufacturer instructions need to agree. Section 916 does not provide universal installation dimensions; verify the model's instructions rather than reusing a generic detail.
Where to show it
Equipment schedule: heater type, manufacturer, model and applicable standard
Equipment plan and detail: layout coordinated with manufacturer instructions
Product submittal: documentation supporting the specified standard and installation
Do
Identify the equipment category before assigning the standard.
Verify whether the portable-residential-spa exception applies.
Recheck installation instructions when the selected model changes.
Do not
Use one standard for every pool and spa heater.
Treat the exception as permission to omit manufacturer instructions.
Accept a substitution based only on matching heating capacity.
Field tip
For a heater replacement, compare the new model's installation instructions with the existing pad, connections and surrounding space before approving reuse. An existing layout is not proof that the replacement will fit its installation requirements. Next: #187 — IMC 917 Cooking Appliances.
In Florida
In Florida the mechanical code is the 2023 FBC-Mechanical (8th Edition), which is based on the 2021 IMC and generally follows the same Chapter 9 numbering. Confirm the Florida section text, any Florida amendment and the referenced standard editions before relying on a 2024 IMC detail. The 9th Edition applies to permit applications on or after 12/31/2026 (state adoption pending).
Questions to settle before design
Heat pump, electric resistance or fuel-fired? The standard follows the type.
Is it a portable residential spa (the exception) or a permanently installed pool or spa heater?
Where will the heater sit relative to the clearances and service space in the manufacturer's instructions?
MasterBuild field checklist
Read the nameplate: confirm the heater type and the standard it is listed to.
Compare the existing pad, piping and electrical connections with the new model's instructions.
Re-check service clearances after fences, screening and landscaping are installed.
MasterBuild recommendation: process steps for design and site review, not code text.
Where MasterBuild helps
PE-led MEP design in Miami, or send your project background. The fee is quoted in writing before work starts.
Code basis
2024 IMC Section 916 model-code education from the owner-published Daily Code Talk. Confirm the locally adopted edition and amendments, the selected product listing and manufacturer instructions, and the authority having jurisdiction. Read the ICC 2024 IMC Chapter 9 for the complete model-code provisions.