Pentair Max-E-Therm® 400 Natural Gas Pool & Spa Heater 400K BTU SR400NA

Pentair Max-E-Therm® 400 Natural Gas Pool & Spa Heater 400K BTU SR400NA

Pentair Max-E-Therm® 400 Natural Gas Pool & Spa Heater 400K BTU SR400NA

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For indoor or outdoor installations on pools and spas. Features include an LED temperature readout with dual thermostat controls, temperature safety lockout, and 6-position control panel. PMG burner technology requires no outdoor draft hood. Proven Dura-Glas rust-proof construction with plastic manifold and PVC union connections. Heavy-duty unit with cupro-nickel exchanger stands up to the harshest of applications, like low pH, high flow or heavy use.

An Eco Select Choice: Max-E-Therm high performance heaters offer best-in-class energy efficiency. Plus, they are certified for low NOx emissions, making them eco-friendly favorites.

Max-E-Therm Features:

  • Lightweight - Lightest heater in its class
  • Compact Design - Ideal for retro-fit installation
  • Easy to Switch - Change gas sources with installation of separate orifice
  • Environmentally Friendly - All units are low NOx
  • Rustproof Housing Sleek, matte black enclosure is made of Dura-Glass - an exclusive Sta-Rite material that handles the heat and weathers the elements
  • Lower Operating Costs - 84% efficiency rating - rated 1st in its class for highest energy efficiency
  • Custom or Retrofit - Direct-connects to Sta-Rite System:3 Mod Media filter or easily fits other systems

First in its class - Sta-Rite Max-E-Therm Low NOx heaters offer the best in pool heating.

  • Indulge in the warmth of your pool even as cool weather approaches without a single concern. Max-E-Therm offers advanced technology - a weather-proof frame, effortless controls, and an environmentally conscience exhaust.
  • Perfect for pools and spas, each Max-E-Therm features an LED temperature readout with dual thermostat controls, 6-position control panel and PVC union connections.
  • Start Saving Its high efficiency rating makes the Sta-Rite Max-E-Therm extremely economical to operate.
  • The heat is on Designed for faster heat-ups , why wait to enjoy that soothing swim?
  • A view from the top Top-mounted control panel has large format digital display for easy viewing.
  • Self diagnostics Control panel indicator lights pinpoint heater or system conditions, which can save money through faster troubleshooting (if required).
  • Easy on the environment Certified for low NOx emissions and outperforms industry standards for air pollution exhaust.
  • Tough exterior Heater enclosure is made of Dura-Glas , an exclusive Sta-Rite thermoplastic resin that handles the heat and weathers the elements.



Upgraded shipping options are available, just select your rate upon checkout! Check out the Expedited Shipping Section below for more details.

Hours Of Operation: 

Monday – Friday: 8:00 am to 4:00 pm

Saturday & Sunday: CLOSED 

We can ship to virtually any address in the world. Note that there are restrictions on some products, and some products cannot be shipped to international destinations.


When you place an order, we will estimate shipping and delivery dates for you. Shipping date estimates may appear on the shipping quotes page. You will receive constant updates on stages of shipping statuses. Order Placed, Order Shipped, and even Order Delivered.

  • All Orders Ship Free “Standard” To USA Domestic Mailing Addresses.
  • All Pool Pumps/Vacuums will be subject to restocking fee if rebate/warranty has been issued by manufacturer. 
  • We proudly ship with FedEx, USPS, UPS, and OnTrac.***
  • Some Orders may receive a 3-5 day handling time before shipment.
  • Certain items will be upgraded for shipping…ON US!
  • Orders above $300 could be required to have signature confirmation
  • All Pool Pumps and Pool Vacuums WILL require signature upon delivery
  • Some Expedited Shipping will incur additional handling time ****

***Shipping Carrier is determined upon delivery speed needed for each order. Paid Expedited Shipping will be shipped with speed requested but Carriers are subject to change without notice.

**** Handling time varies with inventory and availability. Please reach out with any questions or concerns regarding the inventory of your item.


  • All custom orders are NON-REFUNDABLE.
  • Once deposit is made and item is ordered NO refunds/credits are available.
  • All custom order sales are final and CANNOT be returned.
  • Non-Refundable Deposits cannot be transferred if your order is canceled, for any reason.
  • Non-Refundable Deposits cannot be reinstated and placed on a different order.
  • Non-Refundable Deposits may be refunded upon cancellation only in the rare case that the item’s delivery date has been delayed by more than 90 days from the original order date.


We do NOT allow changes in address with Carriers after items shipped. 

United States Post Office (USPS) Notice:
Please allow all First Class Packages 7-10 business days for delivery. If items are stuck in transit, please allow an additional 48-72 hours for tracking information to update. For all packages marked as “Delivered” but did not arrive, please allow 48-72 hours before contacting us for more information.

Shipping Days and Cut-Off Times: 

We ship all orders Monday – Friday. We are closed on the weekends.


All International Order Sales are FINAL and are not eligible for returns/exchanges. Please contact us for more information regarding your product before ordering.


We do not allow changes in address with Carrier after items are shipped. 


We offer additional shipping speeds on any item in stock! If the item is available to purchase then additional shipping speeds are available. You can use the Expedited Shipping tab in each product to determine shipping speed available. To see full price for shipping, you must continue to checkout with your item.

  • Shipping Carrier is determined upon delivery speed needed for each order. Paid Expedited Shipping will be shipped with speed requested but Carriers are subject to change without notice.
  • Handling time varies with inventory and availability. We will contact you if the item is not eligible to meet your shipping speeds.

PLEASE NOTE: We do not allow changes in address with Carrier after items are shipped.


  • Even though we strive on our perfect inventory systems and shipping, we request that all items must be inspected by homeowners for discrepancy within 48 hours of receiving the product to make a shipping, missing, or damage claim.
  • All products are eligible for returns, or exchanges, up to 30 days from delivery.
  • All products are subject to manufacture warranty from day 1 up to when the warranty ends.
  • Returns require a Returns Merchandise Authorization (RMA) form filled out below or call us for help.
  • You are responsible for the cost of shipping the merchandise back to us. The returned item must be returned in as new condition, just like it was delivered to you. If you require a shipping label, the cost of the label will be deducted from your refund upon return.
  • All items must be returned in manufactures packaging, and all contents of the item shipped to you must be returned as well, such as warranty cards, product registration cards, and manuals. Items without original packaging are subject to a restocking fee.
  • All returns, return to sender packages, and refused packages are subject to a 20% restocking fee based off condition of return.
  • All refused items will received a 20% restocking fee.
  • All Caretaker heads with a non-factory installed nozzle that was installed by homeowner/pool professional will receive a 20% restock fee.
  • All Pop Up Head Reamer Tools are not returnable. If item is returned, no refund will be given.
  • Items that have been incorrectly installed or broken during installation may not be covered under return policy.
  • Returns without an RMA or refused at delivery will result in your credit being delayed or denied.
  • In case of misprinted pricing, your order will not be fulfilled and your money will be credited back to you within 24 business hours.
  • If any exchange items are out of stock upon return, the item will be delivered as soon as the item arrives in our warehouse in the order they were received.
  • To obtain an RMA: Please complete the section below describing your return request.

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