A compact, high-efficiency gas pool and spa heater featuring a rustproof Dura-Glas composite housing and intuitive digital controls. Engineered by Pentair, the Sta-Rite Max-E-Therm series combines fast heat-up performance with rugged weatherproof construction built to handle demanding Canadian outdoor environments. Available in 200,000, 333,000, and 400,000 BTU/h capacities for natural gas or propane installations, the Max-E-Therm delivers 84% thermal efficiency, a premix combustion blower system, and hot-surface ignition.
Technical specifications
| Heating Type | Gas Heater |
|---|---|
| Warranty | MasterTemp® & Max-E-Therm® High-Performance Pool & Spa Heaters 2 YEARS Standard Warranty – 1 Year Minimum Inground products purchased from a retail store (brick & mortar), pool builder, or pool service company receive a minimum of one-year parts and labor warranty when professionally installed. Source: Pentair warrantyWarranty is provided by the manufacturer under its own terms. See the source link for full details. |
Key features
- Rustproof Dura-Glas composite housing — sleek, rounded composite exterior eliminates metal corrosion, peeling paint, and rust stains on the pool equipment pad.
- Premix combustion with induced draft blower — completely enclosed air/gas mixing system provides stable flame control and clean combustion even under variable outdoor wind conditions.
- Hot-surface ignition (HSI) — direct electronic silicon carbide igniter eliminates standing pilot lights, reducing standby fuel consumption.
- Precision digital dual-temperature display — top-mounted rotatable control panel features dual digital thermostats for seamless pool and spa temperature switching.
- Smart automation ready — integrates directly with Pentair IntelliCenter, IntelliTouch, and EasyTouch automation systems via standard two-wire communication.
- Direct-vent indoor capability — certified for outdoor installation as well as indoor mechanical room ventilation using certified Category III or IV stainless venting.
Sizing guide
| Model | Rated input | Typical pool surface area | Typical pool volume | Application |
|---|---|---|---|---|
| SR200 | 200,000 BTU/h | Up to 450 sq ft | Up to 55,000 L (14,500 US gal) | Standalone spas and smaller in-ground pools |
| SR333 | 333,000 BTU/h | Up to 750 sq ft | Up to 95,000 L (25,000 US gal) | Mid-size in-ground pools and rapid spa heating |
| SR400 | 400,000 BTU/h | Up to 1,000 sq ft | Up to 130,000 L (34,000 US gal) | Large residential pools and extended shoulder seasons |
Specifications
Performance
| Specification | SR200NA / LP | SR333NA / LP | SR400NA / LP |
|---|---|---|---|
| Input capacity | 200,000 BTU/h (58.6 kW) | 333,000 BTU/h (97.6 kW) | 400,000 BTU/h (117.2 kW) |
| Thermal efficiency | 84.0% | 84.0% | 84.0% |
| Ignition type | Direct hot-surface ignition (HSI) | Direct hot-surface ignition (HSI) | Direct hot-surface ignition (HSI) |
| Blower system | Induced draft combustion blower | Induced draft combustion blower | Induced draft combustion blower |
| Heat exchanger | Fin-tube copper with bronze headers | Fin-tube copper with bronze headers | Fin-tube copper with bronze headers |
| Emissions profile | Low-NOx certified (<40 ng/J) | Low-NOx certified (<40 ng/J) | Low-NOx certified (<40 ng/J) |
Hydraulic & plumbing
| Specification | Value |
|---|---|
| Plumbing connection size | 2 in. CPVC slip unions included (reversible header for left or right piping) |
| Minimum water flow rate | 40 US gpm (151 L/min) across all sizes |
| Maximum water flow rate | 120 US gpm (454 L/min); external manual bypass required above 120 gpm |
| Internal bypass valve | Automatic built-in thermal regulating bypass valve |
| Maximum working pressure | 50 psi (345 kPa) |
Fuel supply & electrical
| Specification | Natural gas models (NA) | Propane models (LP) |
|---|---|---|
| Fuel inlet connection | 3/4 in. NPT female | 3/4 in. NPT female |
| Gas supply pressure (inlet min / max) | 4.0 in. w.c. / 14.0 in. w.c. | 10.0 in. w.c. / 14.0 in. w.c. |
| Manifold operating pressure | Normal: 3.5 in. w.c. | Normal: 10.0 in. w.c. |
| Electrical supply | 115 V AC or 230 V AC, 60 Hz, single phase (convertible field plug) | 115 V AC or 230 V AC, 60 Hz, single phase (convertible field plug) |
| Operating current | 5.5 A at 115 V AC / 3.0 A at 230 V AC | 5.5 A at 115 V AC / 3.0 A at 230 V AC |
Cabinet dimensions & weight
| Dimension | SR200 | SR333 | SR400 |
|---|---|---|---|
| Height | 30.18 in. (767 mm) | 30.18 in. (767 mm) | 30.18 in. (767 mm) |
| Width (cabinet diameter) | 28.14 in. (715 mm) | 28.14 in. (715 mm) | 28.14 in. (715 mm) |
| Depth (front to back) | 33.00 in. (838 mm) | 33.00 in. (838 mm) | 33.00 in. (838 mm) |
| Shipping weight | 128 lb (58.1 kg) | 138 lb (62.6 kg) | 149 lb (67.6 kg) |
Before you buy
- Gas lines, meter regulators, and venting must be sized and installed in compliance with CSA B149.1 (Natural Gas and Propane Installation Code) and local utility standards by a licensed gas technician.
- Electrical connections require a dedicated 15 A 120 V or 240 V branch circuit compliant with the Canadian Electrical Code (CSA C22.1). Ensure proper bonding to the pool bonding grid with a minimum 6 AWG copper conductor.
- Maintain minimum clearances from combustible construction: 6 in. on top, 6 in. on rear, 6 in. on right side, and 12 in. on water connection side. Provide 36 in. front clearance for maintenance access.
- Maintain balanced water chemistry (pH 7.4–7.6, total alkalinity 80–120 ppm, calcium hardness 200–400 ppm) to ensure long heat exchanger operating life.
- For winter freeze protection in cold climates, drain all water by opening the manifold drain plug and clearing connecting piping with compressed air.
Have questions about gas line sizing or selecting between 200K, 333K, or 400K BTU/h? Request a product quote or see the manufacturer documents below.
Frequently asked questions
Does the Max-E-Therm feature a reversible water header?
Yes. The plumbing connections can be reversed from the factory right-hand side to left-hand side in the field to match existing equipment pad pipe runs.
What is the natural gas supply pressure requirement?
Supply gas pressure must measure between 4.0 inches W.C. minimum and 14.0 inches W.C. maximum during firing load. A licensed gas technician must verify line sizing under CSA B149.1.
Is the Max-E-Therm certified as Low-NOx?
Yes. The unit produces low nitrogen oxide emissions under 40 ng/J, meeting all Canadian environmental air quality standards.
Can the Max-E-Therm connect to automated pool controllers?
Yes. The heater supports two-wire connection to Pentair IntelliCenter, EasyTouch, and compatible digital pool automation systems.
What clearance is needed around the circular housing?
Allow 6 inches (150 mm) of clearance on non-plumbing sides, 12 inches (300 mm) on the plumbing side, 18 inches (450 mm) for control panel access, and unrestricted overhead clearance.
How do I winterize the Max-E-Therm for sub-zero temperatures?
Turn off electrical power and shut off the gas supply. Remove the water header drain plug, disconnect the PVC union couplings, blow out any standing water inside the exchanger with low-pressure air, and fit a protective cover.
Documents
- Specification brochure — Sta-Rite Max-E-Therm (English) (PDF)
- Installation and user's guide — Sta-Rite Max-E-Therm (English) (PDF)
- Guide d'installation et d'utilisation — Sta-Rite Max-E-Therm (French) (PDF)
- Engineering submittal data sheet — Sta-Rite Max-E-Therm (PDF)
Specifications sourced from Pentair Sta-Rite Max-E-Therm Installation and User's Guide (P/N 473435 Rev D), brochure (P/N STA-MAXBR-EN), and engineering submittal data. Specifications are subject to change by the manufacturer. View the Pentair Sta-Rite Max-E-Therm manual (PDF).
Common questions
Is installation included?
No. AVL Shop sells equipment only. Installation is done by an independent licensed contractor that you hire.
How is freight charged?
Freight cost is included in your written quote before you pay.
What warranty does this product have?
The manufacturer warranty applies. Where we have the manufacturer’s exact wording, it is shown in the Warranty row of the specifications on this page, with a link to the source.
How do I get a quote?
Use Request a quote on this page and send the model and your city or postal code.