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Pentair MasterTemp® Natural Gas High Performance Heater 300K BTU

by Pentair
$4,753.44

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✓ Authorized Dealer
✓ Free Shipping
✓ Manufacturer Warranty
✓ Expert Support

The Pentair MasterTemp® Natural Gas High Performance Heater 300K BTU offers all the efficiency, convenience, and reliability features you want in a pool heater — plus a lot more. As easy to use as your home heating system, with a user-friendly LCD display and troubleshoot icons that make system operation and monitoring a snap. The compact design and super-quiet operation won't intrude on your poolside leisure time.

Built by Pentair with a heavy-duty cupro-nickel heat exchanger that stands up to the harshest applications — low pH, high flow, or heavy use — the MasterTemp 300K BTU sits between the 250K and 400K in the lineup, delivering best-in-class energy efficiency. CSA certified. Backed by a 2-year warranty.

⚠️ Professional Installation Required. Pool heater installation involves gas line connections and electrical wiring. Always use a licensed contractor to ensure safety, code compliance, and warranty validity.

Key Features

300,000 BTU Output

Upper mid-range natural gas heating — between 250K and 400K in the MasterTemp lineup.

Cupro-Nickel Heat Exchanger (HD)

Heavy-duty exchanger withstands low pH, high flow, and heavy use applications.

Best-in-Class Energy Efficiency

Green certified — outperforms industry standards for efficiency.

LCD Display with Troubleshoot Icons

User-friendly display makes operation and monitoring simple.

Compact, Quiet Design

Same 23-inch wide cabinet as other MasterTemp models — quiet operation.

CSA Certified

Meets North American safety standards for gas-fired pool heaters.

Indoor and Outdoor Rated

Suitable for both indoor and outdoor pool and spa installations.

2-Year Warranty

Pentair residential warranty coverage.

Who It's For

  • Pool and spa owners whose heat load falls between the 250K and 400K BTU MasterTemp models
  • Salt water and chemically demanding pools that benefit from a cupro-nickel heat exchanger
  • Indoor and outdoor installations
  • Anyone who wants maximum heating output from the compact 23-inch MasterTemp cabinet

Specifications

Heating Performance

BTU Input 300,000 BTU
Fuel Type Natural Gas
Max Flow Rate 120 GPM

Construction

Heat Exchanger Cupro-Nickel (HD)
Control Type Digital (LCD with Troubleshoot Icons)

Installation

Gas Connection 0.75 in
Voltage 120V / 240V
Frequency 60 Hz
Phase Single
Application Indoor / Outdoor / Pool / Spa

Physical

Product Weight 136 lb
Cabinet Dimensions 23 W × 28.2 D × 21 H in
Shipping Dimensions 36 × 25 × 30 in

Approvals & Warranty

Certifications CSA Certified
Energy Efficient Yes (Green Certified)
Warranty 2 Years

What's in the Box

  • Pentair MasterTemp 300K BTU Natural Gas Heater
  • Union Fittings
  • User Manual

Warranty

The MasterTemp 300K BTU NG comes with a 2-year manufacturer warranty from Pentair. Clearflow Pool Supply is an authorized Pentair dealer and will assist with any warranty service needed.

Downloads

Frequently Asked Questions

Where does the 300K BTU fit in the MasterTemp lineup?

The MasterTemp is available in 125K, 200K, 250K, 300K, and 400K BTU sizes. The 300K sits between the 250K (suited for pools up to ~30,000 gallons) and the 400K (suited for pools up to ~50,000 gallons). All full-size MasterTemp models share the same 23-inch wide cabinet, cupro-nickel heat exchanger, and LCD display.

Does this heater require professional installation?

Yes. Gas heater installation involves connecting to a natural gas supply line, electrical wiring, and proper venting. A licensed pool contractor or plumber must perform the installation to ensure safety, local code compliance, and warranty validity.

Is it compatible with salt water pools?

Yes. The heavy-duty cupro-nickel heat exchanger provides superior resistance to salt water corrosion, making the MasterTemp 300K a strong choice for salt water pool installations.

What size pool is the 300K BTU suitable for?

As a general guideline, 300,000 BTU is typically suited for pools in the 25,000–40,000 gallon range depending on climate, desired temperature rise, and heat loss factors. A licensed pool professional can calculate the correct BTU requirement for your specific pool and location.

Can it be used indoors?

Yes. The MasterTemp is rated for both indoor and outdoor installation. Indoor installations require proper venting per local code. Consult the install guide and a licensed contractor for indoor venting requirements.

Description
✓ Authorized Dealer ✓ Free Shipping ✓ Manufacturer Warranty ✓ Expert Support

The Pentair MasterTemp® Natural Gas High Performance Heater 300K BTU offers all the efficiency, convenience, and reliability features you want in a pool heater — plus a lot more. As easy to use as your home heating system, with a user-friendly LCD display and troubleshoot icons that make system operation and monitoring a snap. The compact design and super-quiet operation won't intrude on your poolside leisure time.

Built by Pentair with a heavy-duty cupro-nickel heat exchanger that stands up to the harshest applications — low pH, high flow, or heavy use — the MasterTemp 300K BTU sits between the 250K and 400K in the lineup, delivering best-in-class energy efficiency. CSA certified. Backed by a 2-year warranty.

⚠️ Professional Installation Required. Pool heater installation involves gas line connections and electrical wiring. Always use a licensed contractor to ensure safety, code compliance, and warranty validity.

Key Features

300,000 BTU Output

Upper mid-range natural gas heating — between 250K and 400K in the MasterTemp lineup.

Cupro-Nickel Heat Exchanger (HD)

Heavy-duty exchanger withstands low pH, high flow, and heavy use applications.

Best-in-Class Energy Efficiency

Green certified — outperforms industry standards for efficiency.

LCD Display with Troubleshoot Icons

User-friendly display makes operation and monitoring simple.

Compact, Quiet Design

Same 23-inch wide cabinet as other MasterTemp models — quiet operation.

CSA Certified

Meets North American safety standards for gas-fired pool heaters.

Indoor and Outdoor Rated

Suitable for both indoor and outdoor pool and spa installations.

2-Year Warranty

Pentair residential warranty coverage.

Who It's For

  • Pool and spa owners whose heat load falls between the 250K and 400K BTU MasterTemp models
  • Salt water and chemically demanding pools that benefit from a cupro-nickel heat exchanger
  • Indoor and outdoor installations
  • Anyone who wants maximum heating output from the compact 23-inch MasterTemp cabinet

Specifications

Heating Performance

BTU Input 300,000 BTU
Fuel Type Natural Gas
Max Flow Rate 120 GPM

Construction

Heat Exchanger Cupro-Nickel (HD)
Control Type Digital (LCD with Troubleshoot Icons)

Installation

Gas Connection 0.75 in
Voltage 120V / 240V
Frequency 60 Hz
Phase Single
Application Indoor / Outdoor / Pool / Spa

Physical

Product Weight 136 lb
Cabinet Dimensions 23 W × 28.2 D × 21 H in
Shipping Dimensions 36 × 25 × 30 in

Approvals & Warranty

Certifications CSA Certified
Energy Efficient Yes (Green Certified)
Warranty 2 Years

What's in the Box

  • Pentair MasterTemp 300K BTU Natural Gas Heater
  • Union Fittings
  • User Manual

Warranty

The MasterTemp 300K BTU NG comes with a 2-year manufacturer warranty from Pentair. Clearflow Pool Supply is an authorized Pentair dealer and will assist with any warranty service needed.

Downloads

Frequently Asked Questions

Where does the 300K BTU fit in the MasterTemp lineup?

The MasterTemp is available in 125K, 200K, 250K, 300K, and 400K BTU sizes. The 300K sits between the 250K (suited for pools up to ~30,000 gallons) and the 400K (suited for pools up to ~50,000 gallons). All full-size MasterTemp models share the same 23-inch wide cabinet, cupro-nickel heat exchanger, and LCD display.

Does this heater require professional installation?

Yes. Gas heater installation involves connecting to a natural gas supply line, electrical wiring, and proper venting. A licensed pool contractor or plumber must perform the installation to ensure safety, local code compliance, and warranty validity.

Is it compatible with salt water pools?

Yes. The heavy-duty cupro-nickel heat exchanger provides superior resistance to salt water corrosion, making the MasterTemp 300K a strong choice for salt water pool installations.

What size pool is the 300K BTU suitable for?

As a general guideline, 300,000 BTU is typically suited for pools in the 25,000–40,000 gallon range depending on climate, desired temperature rise, and heat loss factors. A licensed pool professional can calculate the correct BTU requirement for your specific pool and location.

Can it be used indoors?

Yes. The MasterTemp is rated for both indoor and outdoor installation. Indoor installations require proper venting per local code. Consult the install guide and a licensed contractor for indoor venting requirements.

Shipping

Shipping Policy

At ClearFlow Pool Supply, we keep things simple.

👉 Free shipping on all orders within the United States.
No hidden fees. No surprises.


Order Confirmation

As soon as you place your order, you’ll receive an order confirmation email.

This means:

  • we’ve received your order
  • your payment method has been pre-authorized

Once your order is in our system, we verify:

  • product availability
  • inventory status with our suppliers

If an item is unavailable or backordered, we will:

  • void the pre-authorization
  • contact you promptly to discuss alternatives

If your item is in stock and ready to ship (typically within 3–5 business days), your order will be processed and prepared for shipment.


Order Shipment

Orders that are in stock will typically ship within 3 business days.

You will receive a shipping confirmation email with tracking details within 24 hours of your order leaving the warehouse.

If you do not receive tracking information within 4 business days, please contact us at:

👉 support@clearflowpoolsupply.com 


Shipping Scope

We currently ship to customers within the United States.

Due to the size and nature of many pool equipment products, some orders may ship via freight carriers. Delivery times may vary depending on location and product availability.


International Orders

At this time, our products are designed and configured for the U.S. market, operating on 110V electrical systems and meeting U.S. safety standards.

We may be able to accommodate international orders on a case-by-case basis.
If you are located outside the United States, please contact us to request a custom shipping quote.


Damaged Shipments

Please inspect your order upon delivery.

If you notice any damage:

  • note it with the carrier before signing
  • or refuse the delivery if damage is severe

If you accept the delivery:

👉 Take clear photos of:

  • the packaging
  • the damaged product

Then email us immediately at:

👉 support@clearflowpoolsupply.com

We will work with you quickly to resolve the issue.


Returns

For full details on returns, please visit our Returns Policy page.

Why Buy from Us

Why Buy From Us

We understand—you have options when it comes to buying pool equipment online.

At ClearFlow Pool Supply, our goal is simple:

👉 provide reliable products
👉 offer a straightforward buying experience
👉 and support you every step of the way

Here’s what sets us apart.


Free Shipping Across the U.S.

No hidden fees. No surprises.

All orders ship free within the United States, including large and heavy equipment.


Competitive Pricing

We work to offer strong, competitive pricing across our entire catalog.

If you find the same product available online at a lower total price, feel free to reach out—we’re happy to review it.


30-Day Return Policy

If your product isn’t the right fit, we offer a 30-day return window.

We aim to make the process as simple and straightforward as possible.
(See our Returns Policy for full details.)


Reliable Equipment

We focus on products that matter:

  • durable
  • proven
  • built for long-term use

Our goal is to help you avoid the frustration of unreliable or low-quality equipment.


Customer-Focused Support

We’re here to help before and after your purchase.

Whether you’re:

  • replacing a component
  • upgrading your system
  • or choosing equipment for the first time

👉 we’re here to make the process easier


Our Commitment

We stand behind what we sell.

If something isn’t right, we’ll work with you to resolve it quickly and fairly.


Price Match Policy

If you find the same product offered at a lower total price (including shipping), contact us at:

👉 support@clearflowpoolsupply.com

We’ll review the offer and do our best to match it.

Description
✓ Authorized Dealer ✓ Free Shipping ✓ Manufacturer Warranty ✓ Expert Support

The Pentair MasterTemp® Natural Gas High Performance Heater 300K BTU offers all the efficiency, convenience, and reliability features you want in a pool heater — plus a lot more. As easy to use as your home heating system, with a user-friendly LCD display and troubleshoot icons that make system operation and monitoring a snap. The compact design and super-quiet operation won't intrude on your poolside leisure time.

Built by Pentair with a heavy-duty cupro-nickel heat exchanger that stands up to the harshest applications — low pH, high flow, or heavy use — the MasterTemp 300K BTU sits between the 250K and 400K in the lineup, delivering best-in-class energy efficiency. CSA certified. Backed by a 2-year warranty.

⚠️ Professional Installation Required. Pool heater installation involves gas line connections and electrical wiring. Always use a licensed contractor to ensure safety, code compliance, and warranty validity.

Key Features

300,000 BTU Output

Upper mid-range natural gas heating — between 250K and 400K in the MasterTemp lineup.

Cupro-Nickel Heat Exchanger (HD)

Heavy-duty exchanger withstands low pH, high flow, and heavy use applications.

Best-in-Class Energy Efficiency

Green certified — outperforms industry standards for efficiency.

LCD Display with Troubleshoot Icons

User-friendly display makes operation and monitoring simple.

Compact, Quiet Design

Same 23-inch wide cabinet as other MasterTemp models — quiet operation.

CSA Certified

Meets North American safety standards for gas-fired pool heaters.

Indoor and Outdoor Rated

Suitable for both indoor and outdoor pool and spa installations.

2-Year Warranty

Pentair residential warranty coverage.

Who It's For

  • Pool and spa owners whose heat load falls between the 250K and 400K BTU MasterTemp models
  • Salt water and chemically demanding pools that benefit from a cupro-nickel heat exchanger
  • Indoor and outdoor installations
  • Anyone who wants maximum heating output from the compact 23-inch MasterTemp cabinet

Specifications

Heating Performance

BTU Input 300,000 BTU
Fuel Type Natural Gas
Max Flow Rate 120 GPM

Construction

Heat Exchanger Cupro-Nickel (HD)
Control Type Digital (LCD with Troubleshoot Icons)

Installation

Gas Connection 0.75 in
Voltage 120V / 240V
Frequency 60 Hz
Phase Single
Application Indoor / Outdoor / Pool / Spa

Physical

Product Weight 136 lb
Cabinet Dimensions 23 W × 28.2 D × 21 H in
Shipping Dimensions 36 × 25 × 30 in

Approvals & Warranty

Certifications CSA Certified
Energy Efficient Yes (Green Certified)
Warranty 2 Years

What's in the Box

  • Pentair MasterTemp 300K BTU Natural Gas Heater
  • Union Fittings
  • User Manual

Warranty

The MasterTemp 300K BTU NG comes with a 2-year manufacturer warranty from Pentair. Clearflow Pool Supply is an authorized Pentair dealer and will assist with any warranty service needed.

Downloads

Frequently Asked Questions

Where does the 300K BTU fit in the MasterTemp lineup?

The MasterTemp is available in 125K, 200K, 250K, 300K, and 400K BTU sizes. The 300K sits between the 250K (suited for pools up to ~30,000 gallons) and the 400K (suited for pools up to ~50,000 gallons). All full-size MasterTemp models share the same 23-inch wide cabinet, cupro-nickel heat exchanger, and LCD display.

Does this heater require professional installation?

Yes. Gas heater installation involves connecting to a natural gas supply line, electrical wiring, and proper venting. A licensed pool contractor or plumber must perform the installation to ensure safety, local code compliance, and warranty validity.

Is it compatible with salt water pools?

Yes. The heavy-duty cupro-nickel heat exchanger provides superior resistance to salt water corrosion, making the MasterTemp 300K a strong choice for salt water pool installations.

What size pool is the 300K BTU suitable for?

As a general guideline, 300,000 BTU is typically suited for pools in the 25,000–40,000 gallon range depending on climate, desired temperature rise, and heat loss factors. A licensed pool professional can calculate the correct BTU requirement for your specific pool and location.

Can it be used indoors?

Yes. The MasterTemp is rated for both indoor and outdoor installation. Indoor installations require proper venting per local code. Consult the install guide and a licensed contractor for indoor venting requirements.

Shipping

Shipping Policy

At ClearFlow Pool Supply, we keep things simple.

👉 Free shipping on all orders within the United States.
No hidden fees. No surprises.


Order Confirmation

As soon as you place your order, you’ll receive an order confirmation email.

This means:

  • we’ve received your order
  • your payment method has been pre-authorized

Once your order is in our system, we verify:

  • product availability
  • inventory status with our suppliers

If an item is unavailable or backordered, we will:

  • void the pre-authorization
  • contact you promptly to discuss alternatives

If your item is in stock and ready to ship (typically within 3–5 business days), your order will be processed and prepared for shipment.


Order Shipment

Orders that are in stock will typically ship within 3 business days.

You will receive a shipping confirmation email with tracking details within 24 hours of your order leaving the warehouse.

If you do not receive tracking information within 4 business days, please contact us at:

👉 support@clearflowpoolsupply.com 


Shipping Scope

We currently ship to customers within the United States.

Due to the size and nature of many pool equipment products, some orders may ship via freight carriers. Delivery times may vary depending on location and product availability.


International Orders

At this time, our products are designed and configured for the U.S. market, operating on 110V electrical systems and meeting U.S. safety standards.

We may be able to accommodate international orders on a case-by-case basis.
If you are located outside the United States, please contact us to request a custom shipping quote.


Damaged Shipments

Please inspect your order upon delivery.

If you notice any damage:

  • note it with the carrier before signing
  • or refuse the delivery if damage is severe

If you accept the delivery:

👉 Take clear photos of:

  • the packaging
  • the damaged product

Then email us immediately at:

👉 support@clearflowpoolsupply.com

We will work with you quickly to resolve the issue.


Returns

For full details on returns, please visit our Returns Policy page.

Why Buy from Us

Why Buy From Us

We understand—you have options when it comes to buying pool equipment online.

At ClearFlow Pool Supply, our goal is simple:

👉 provide reliable products
👉 offer a straightforward buying experience
👉 and support you every step of the way

Here’s what sets us apart.


Free Shipping Across the U.S.

No hidden fees. No surprises.

All orders ship free within the United States, including large and heavy equipment.


Competitive Pricing

We work to offer strong, competitive pricing across our entire catalog.

If you find the same product available online at a lower total price, feel free to reach out—we’re happy to review it.


30-Day Return Policy

If your product isn’t the right fit, we offer a 30-day return window.

We aim to make the process as simple and straightforward as possible.
(See our Returns Policy for full details.)


Reliable Equipment

We focus on products that matter:

  • durable
  • proven
  • built for long-term use

Our goal is to help you avoid the frustration of unreliable or low-quality equipment.


Customer-Focused Support

We’re here to help before and after your purchase.

Whether you’re:

  • replacing a component
  • upgrading your system
  • or choosing equipment for the first time

👉 we’re here to make the process easier


Our Commitment

We stand behind what we sell.

If something isn’t right, we’ll work with you to resolve it quickly and fairly.


Price Match Policy

If you find the same product offered at a lower total price (including shipping), contact us at:

👉 support@clearflowpoolsupply.com

We’ll review the offer and do our best to match it.