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Home Pool Pool & Spa Heaters Pentair & Sta-Rite Pool & Spa Heaters Pentair MasterTemp 125 Low NOx Pool Heater - Electronic Ignition - Natural Gas with Electrical Plug-In Cord - 125,000 BTU - EC-462024
NOTICE: The pool & spa industry continues to face industry-wide shortages on many products that most vendors expect to last late into 2022. We're allowing items to be purchased so that customers who choose to wait will have their order shipped when product is available. Most vendors are not providing any ETA on when items will be available. WE WILL EMAIL YOU RIGHT AWAY IF YOUR ITEM IS BACKORDERED. 

Pentair MasterTemp 125 Low NOx Pool Heater - Electronic Ignition - Natural Gas with Electrical Plug-In Cord - 125,000 BTU - EC-462024

Pentair MasterTemp 125 Low NOx Pool Heater - Electronic Ignition - Natural Gas with Electrical Plug-In Cord - 125,000 BTU - EC-462024

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  • 82% Energy Efficiency is Highest in its Class
  • 1-1/2" Plumbing-Ideal for Smaller Bodies of Water up to 15,000 Gallons
  • High-Performance, Affordable Heating with Premium Features
  • Pre-Mixed Combustion Technology for Ultra-Fast Heat-Up
  • Easy-to-Use, Digital Display Makes Programming and Monitoring a Cinch.
  • Online part number EC-462024 is the direct replacement for part number 461059
  • Pentair Sta-Rite 4x6 Metal Flue Collar for Indoor Vertical Venting - Negative Pressure for Distance Less Than 8' | 77707-0076
    Indoor Vertical Venting - Negative Pressure 4x6 Metal Flue Collar for Distances Less Than 8' | 77707-0076

  • Pentair Sta-Rite 4x8 Metal Flue Collar for Indoor Vertical Venting - Negative Pressure for Distances Over 8' | 77707-0077
    Indoor Vertical Venting - Negative Pressure 4x8 Metal Flue Collar for Distances Over 8' | 77707-0077

  • Pentair 4" Stainless Steel Appliance Adapter for Horizontal or Vertical Positive Pressure by Heatfab | 77707-0086
    4" Appliance Adapter Horizontal or Vertical Venting, Positive Pressure by Heatfab | 77707-0086

  • Pentair 4" Stainless Steel Appliance Adapter for Horizontal or Vertical Positive Pressure Venting by Z-Flex | 77707-0087
    4" Appliance Adapter for Horizontal or Vertical Positive Pressure Venting by Z-Flex | 77707-0087

MasterTemp® 125 High Performance Heater
Introducing! The High-Efficiency, High Technology Heater for Bodies of Water up to 15,000 gallons
The remarkably affordable new MasterTemp 125 heater gives you the energy savings and advanced operating features that were only available from much larger heaters. With its revolutionary pre-mixed gas combustion technology, the MasterTemp 125 heater offers 82% thermal efficiency - the highest of any heater in its category. Its 1-1/2" plumbing is ideal for smaller applications, including aboveground pools, spas and inground pools up to 15,000 gallons. Featuring the first ever rotating, digital display offered in its class, the MasterTemp 125 heater provides valuable information conveniently and at the touch of a button. Plus, its lightweight, compact design makes the MasterTemp 125 heater easier to install than any other heater in its class - reducing labor costs which saves you money.
New Improved Rodent Resistance for the MasterTemp High Performance Heater
The engineers made improvements to reduce gaps and eliminate access points, including advancements to the heater base, all exterior side panels and louvers, the gas valve and water manifold openings, the exhaust opening and the exhaust cover. These subtle, but important, design changes add up to a better heater, from every angle.
In addition to the new rodent resistant improvements, the features and benefits of a MasterTemp High Performance Heater include:
  • Enhanced LCD display and diagnostics include easy to display and front-facing error messages and icons
  • Best-in-class energy efficiency
  • Eco-friendly certified for low, NOx emission and outperforms industry standard
MasterTemp 125 heater features include:
  • 82% energy efficiency is highest in its class.
  • 1-1/2" plumbing - ideal for smaller bodies of water up to 15,000 gallons.
  • High-performance, affordable heating with premium features.
  • Pre-mixed combustion technology for ultra-fast heat-up.
  • Easy-to-use, digitial display makes programming and monitoring a cinch.
  • 125,000 BTU rating.
  • Available in natural gas or propane gas.
  • 120v electrical.
  • Lightweight - easy to handle and ship.
  • Certified for low NOx emissions.
  • Certified for Direct Air Intake with PVC Pipe.
  • Certified for outdoor and indoor vented installations.
These installations instructions are designed for use by qualified personnel only, trained especially for installation of this type of heating equipment and related components. Some states require installation and repair by licensed personnel. If this applies in your state, be sure your contractor bears the appropriate license.

Brand: Pentair
BTU Rating
Gas Type
Natural Gas
Q & A
Start typing your question and we'll check if it was already asked and answered. Learn More
Browse 46 questions Browse 46 questions and 73 answers
Is the power cord shipped inside the master temp 125 to plug into ac outlet?
A shopper on May 22, 2019
Will this heater work with a salt water pool?
George C on Nov 15, 2017
BEST ANSWER: Based on the general specifications of the User Manual, it says, "The heater is designed for the heating of chlorine, bromine or salt system swimming pools and spas. It should NOT be
used as a space heating boiler, or general purpose water heater."
can this unit be used with a small inground spa and does it come in a standing pilot configuration ?
A shopper on Mar 22, 2017
BEST ANSWER: Works great with an inground spa. Electronic ignition requires 110 volt source. Check with your installer for standing pilot configuration?
Going to run it with natural gas for a 24ft above ground pool what do I need to purchase along with the heater we have trench dug?
Randy H on Jul 16, 2019
What does 82% energy efficiency mean?
A shopper on Jul 4, 2017
BEST ANSWER: The heater gives you $.82 worth of heat for every $1.00 in fuel you spend. It burns all the gas coming in. The heat coming from the exhaust vent is just going into the atmosphere, not the water. That's the 18% that is not going into the water.
Can this heater be used with a salt chlorination system?
A shopper on Dec 10, 2016
BEST ANSWER: I sold my home when I bought this heater and unfortunately, do not know if the heater can be used a salt chlorination system. Sorry.??
Is this hard wired or does it have a pig tail?
Charles D on Sep 22, 2019
BEST ANSWER: This one specifically comes with a 110V pig tail.
how hot does the water get?
A shopper on Mar 2, 2016
is it for salt / chlorine ?
michael g on Apr 20, 2020
Does this natural gas 125 come with a 110 plug?
A shopper on May 16, 2020
BEST ANSWER: Yes, but caution is not supplied with water flow switch approx 50.00 witch it will not start without. shown on parts list"purchase seprarately."
What type of venting do I need for this heater the size and etc. to go through a wall and up through the ceiling will be used indoors?
Victoria G on May 17, 2018
BEST ANSWER: You'll need to buy an adaptor from pool supply that will connect your heater to 6" single walled exhaust vent, buy a section of "double walled" where it comes into contact with your ceiling/roof and perhaps a condensation drain, we're having quite a bit of condensation running down the vent in our cold climate!
can you set this heater on wood?
A shopper on May 9, 2020
BEST ANSWER: I set mine on 3/4 inch plywood. ran a whole season no problem.The unit doesn't get hot on the bottom.
How hot can the water get and is it warm enough to swim in the winter?
A shopper on Apr 5, 2020
BEST ANSWER: How much water are you trying to heat. A 10k gallon pool has about 80k pounds of water in it.This heater would raise the temperature of that body of water about 1 degree per hour. If the pool is covered it would still take a considerable amount of time to get it warm enough to swim in the winter (depending on your location and starting temperature). If you get strong winds or rain your temperature-gain could be considerably less. If you can afford it, get a larger heater (more BTUs).
how difficult to install--have an existing nat gas heater ?
tony n on Sep 4, 2016
BEST ANSWER: We had ours professionally installed to get the longer warranty , but should have done it on our own. It is a gas line, and two water pipes. Pretty simple. unfortunately ours was not grounded so after a year the coils were eaten away. And that's the one part 500$ not covered by the warranty. Nowe we have to fight the installation company to get that covered. The ground connection is right under the hot air exhaust.
How long to heat up spa?
A shopper on Feb 27, 2016
BEST ANSWER: I have a 24 round above ground pool. It heats it up in just a few hours. Of course it depends on the weather, but I love it. I kept my pool open until mid October and I live in southwestern PA.
Is this electric?
Emily on May 21, 2020
BEST ANSWER: No this a natural gas heater but does need 120v outlet for the controls and fan.
So does this run with a propane tank?
A shopper on Apr 30, 2020
BEST ANSWER: I don’t think so. This one is natural gas. I think you have to have one that is specifically propane. We love ours though. Our grandkids swim all the time since we don’t have to wait for it to warm up after a rain or cool spell.
Does this natural gas 125 come with a 110 plug?
A shopper on May 16, 2020
BEST ANSWER: Yes 3 prong about 6 feet long
Service heater light on and I can't find my book. Any ideas?
A shopper on Aug 16, 2018
BEST ANSWER: Two things , one unplug it wait 30 seconds and plug it back in . Next check you filter pressure and make sure it’s below the requirement
What's the difference bw with cord and without cord ... what cord are they talking about?
Sssss on Jan 27, 2018
BEST ANSWER: With a cord is a normal power cord that you plug into a wall. Without a cord means you would need a whip kit or an existing one that would be hard wired in.
What BTU rating is required for a 20X40 in ground pool?
calvin p on Feb 6, 2017
BEST ANSWER: I agree with Charles. A 400K BTU heater is the recommend heater for your pool.
Is this heater okay for a 15 x 30 above ground pool?
Michael D on Mar 27, 2016
BEST ANSWER: I use this heater for my 18 foot round or 254 sq/ft 52 inch deep above ground with no problem. 15x30 is near double my volume if it is a 52" deep wall.
What size gas pipe is recommended ?
A shopper on Nov 1, 2019
BEST ANSWER: 1/2 gas lines works fine .
Can this be use on a koi pond?
Tony E on Nov 1, 2019
BEST ANSWER: Sure. Make sure you check the specification that address minimum water flow requirements. The heater is equipped with a sensor that monitors water flow. The heater will not run or stay running if water flow is inadequate
Can i get it in electric operated only for use in the Caribbean with 240v?
A shopper on Sep 20, 2019
BEST ANSWER: Use model 461058 instead which can be hard wired and converted to 240V in the filed. It comes pre-wired for 110V but it can be quickly and easily changed during installation. Here is a link for model 461058:

What's the part# for the heat exchanger?
A shopper on Sep 12, 2019
BEST ANSWER: Part number 474971 - attached here.
Pentair Tube Sheet Coil Assembly Kit | 474971
Pentair Tube Sheet Coil Assembly Kit | 474971
How much does this heater weigh?
Karen on Mar 24, 2019
BEST ANSWER: 122 lbs.
what do I need to hook up the Pentair MasterTemp 125Low NOx Pool Heater to my Bestway/Coleman pool? So I would have attach the flexible hose coming from pool to PVC in order to connect with heater?
Mike Y on Oct 5, 2018
BEST ANSWER: I hard piped my heater with 1.5" schedule 40 PVC to and from the pump/filter return line. Pentair provides a 1.5" union at the in and out port to the heater. I also insulated and buried all piping to and from the heater to help reduce heat loss. Make sure you hard pipe the gas lines and follow the plumbing recommendations from Pentair so that you get proper gas flow.
What lines/pipes do you need to hook up to pool?
Mike Y on Oct 5, 2018
BEST ANSWER: What you would need to install this heater is a gas line coming from your meter and the piping from the pool should be 1.5" pvc.
cost to install pool heater ?
bob s on Sep 4, 2018
BEST ANSWER: We don't install items but you may want to check with a company we work with.

4.6 / 5.0
18 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
Rated 5 out of 5
As a resident of California, the law requires LoNox heaters. This one fits the bill and does the job perfectly. Heats the water quickly and very reliable.
December 5, 2015
Rated 5 out of 5
Best heater after trying 3 different competitors
never had a problem with it and have had it over year. I take it in the or winter time
September 5, 2016
over 6 years ago
Rated 4 out of 5
Heats up spa in small amount of time. Great unit for the price. Recommended. <br>
January 7, 2015
Rated 5 out of 5
When you despise shopping do it this way ??
Hi All : Got on-line found our product easily placed the order within minutes we had confirmation and Delivery was on time the guy who delivered it was great he set it in the back yard for us . This was a replacement of our previous unit which was identical, setup time took a few minutes and within a day or two our 21 ft round pool was 90 degrees ????
May 26, 2018
over 4 years ago
Rated 5 out of 5
great experience
I priced this heater with a local pool supply company and the price was almost double. After I ordered it, I received it in less time then they told me . My overall experience was fantastic ! Fyi the heater works great .
July 3, 2017
over 4 years ago
Rated 5 out of 5
Purchase for a 24’ above ground pool 52” deep. Heater had no problem getting water up to set temperature fast. Runs Quite and was easy to install.
October 6, 2020
1 year ago
Rated 5 out of 5
Perfect pool heater
I got a 24ft round above ground Pool it was 62 degrees when I started the heater. 12 hours later it was 77 degrees then the next morning it was 85 degrees now it is maintaining the 85 degrees this tiime of the year the pool would be around 70 with out heater we love the heater
May 16, 2020
over 2 years ago
Rated 5 out of 5
Great heater for the price!
My old heater was replaced with this one and what a difference. We have a 24 ft above ground pool and this heater works great right out of the box. Would recommrnd...
June 1, 2018
over 4 years ago
Rated 5 out of 5
Delivered my heater on time everything is working perfect thanks for the great service
July 18, 2021
11 months ago
Rated 5 out of 5
Very nice unit , does the job well. Easy set up. Turned on the filter / pump , plugged in the heater , set for pool and off it went.
July 17, 2020
over 2 years ago
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Register your Pentair product online at www.pentair.com.

You've always been able to count on the quality and long service life of Pentair products. Pentair uses state of the art workmanship, materials and manufacturing processes to create the most innovative pool and spa equipment anywhere. And now Pentair products can deliver even more value and peace of mind, because Pentair offers extended warranty coverage on select products that are installed by a qualified installer*.
While the majority of Pentair products are covered by a sixty- (60) day warranty, a select number of products qualify for extended warranty coverage.
Select Bundled Products: applies to purchases and qualified installation of a minimum of a pump and filter, and one or more of the following: heaters, heat pumps, control systems, automatic cleaners, lighting, salt chlorine generators or UV sterilizer**
*Note: Qualified Installer - Defined as a licensed professional who charges a fee for his services, and possesses a business license, contractor's license and/or resale permit. Common examples of a "qualified installer" include: Swimming Pool, Home Repair or Landscape Professional; Plumber or Electrician; General Contractor; Heating and Air Conditioning Specialist.
**Note: Bundled products - must be purchased on the same invoice and installed at the same time. If any product within a bundle is ineligible for the bundled warranty coverage then all products within the same bundle will be disqualified from receiving the three (3) year extended warranty coverage for bundled products.
TradeGrade products must be purchased from a retail store (brick & mortar), pool builder or pool service company to receive a one-year, two-year or three-year warranty. If purchased online will only receive a sixty-day limited warranty. View the list of TradeGrade Products.
Ecommerce (EC) products: Products purchased from an Authorized Pentair Online Reseller (products beginning with EC-) receive a one (1) year (parts only) warranty from the date of purchase. The exceptions are: IntelliChlor cells and IntelliFlo SVRS pumps which receive a two (2) year warranty. EC products are not eligible for the bundled three (3) year extended warranty.
Visit www.pentair.com to submit your product warranty registration.
This information was updated on 11/19/2021. For the most current information and full warranty policy please visit www.pentair.com/warranty.

 Adobe Acrobat PDF Warranty Information
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