Home Pool Pool & Spa Heaters Pentair & Sta-Rite Pool & Spa Heaters Pentair MasterTemp 125 Low NOx Pool Heater - Electronic Ignition - Natural Gas without Cord - 125,000 BTU - 461058

Pentair MasterTemp 125 Low NOx Pool Heater - Electronic Ignition - Natural Gas without Cord - 125,000 BTU - 461058

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Pentair MasterTemp 125 Low NOx Pool Heater - Electronic Ignition - Natural Gas without Cord - 125,000 BTU - 461058 Pentair MasterTemp 125 Low NOx Pool Heater - Electronic Ignition - Natural Gas without Cord - 125,000 BTU - 461058

Parts AvailableParts Available
Platinum Preferred Manufacturer
  • 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.
  • Improved Resistance to Rodent Intrusion
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.
  • 120/240 V 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.

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

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 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

Q & A
Start typing your question and we'll check if it was already asked and answered. Learn More
Browse 32 questions Browse 32 questions and 53 answers
Why did you choose this?
Pool Supply Unlimited Store
compact and works well for my hot tub
Mark N on Apr 14, 2019
size i needed , and reviews , info on site $
arden w on Jun 12, 2018
compact and works well for my hot tub
Mark N on Apr 14, 2019
Great price and reasonable shipping rate
Marc S on Jul 23, 2018
size i needed , and reviews , info on site $
arden w on Jun 12, 2018
advertised in kayak
mike w on May 13, 2018
Raj P on Jan 12, 2018
Currently have Pentair pump and filter system and satisfied with their performance. This heater looks like it will fill our needs and allow us to open the pool early in the Spring and keep it open into early Fall. The kids are gonna be happy! ;-)
Joseph S on Dec 19, 2017
/To Replace old Heater with a electrical and rusting problems.
James C on Nov 10, 2017
My Pentair MasterTemp 250 heat exchanger failed but only have a small outside spa so instead of fixing it was cheaper to buy a new smaller unit.
Jennifer B on Nov 1, 2017
I shopped around it was a good price, and I replacing a Pentair heater.
Dennis B on Jun 22, 2017
We have a Pentair filter system
Jeff J on Jun 19, 2017
Advised to order by my installer
Susan G on May 29, 2017
Replacing an existing heater with the same piece of equipment
Valerie B on May 16, 2017
Price. Name.
Frank W on May 11, 2017
great price
grant r on May 10, 2017
Thomas H on Apr 24, 2017
Seen good reviews on your product and also a previous owner and purchaser
Lydia L on Apr 10, 2017
Best in class product
Lola D on Mar 14, 2017
was a good affordable energy efficient option to replace our old heaters and i have had good experiences in the past with Pentairs products and customer service.
Shane H on Feb 9, 2017
Seems like the right fit for my 1000 gallon spa
richard o on Dec 8, 2016
My plumber recommended it to purchase this pool heater
Angie C on Dec 4, 2016
John P on May 27, 2016
Best bang for buck, Pentair good product
Gary K on Feb 11, 2016
Pricing and avaiable
James M on Dec 7, 2015
Good price and availability. Ryan was very helpful when I called.
James K on Sep 25, 2015
Great price and reasonable shipping rate
Marc S on Jul 23, 2018
advertised in kayak
mike w on May 13, 2018
Will this size work on a 15,000 gallon in-ground pool?
A shopper on May 18, 2017
BEST ANSWER: Yes, in my opinion it should work just fine for that size pool. It is a very well designed and a very efficient natural gas heater. It is easy to install, control, and it runs fairly quietly. It is a quality piece of equipment!
I have a 15,000 gal inground pool would a higher BTU heat faster than 125K?
A shopper on May 30, 2017
need the right heater for 24' intec above ground pool 52" deep?
Joshua P on Mar 2, 2019
will this heater be efficient for my spa and 14000 gallon pool ?
James F on Nov 24, 2015
BEST ANSWER: i have a similar sized pool with a small spa (fits about 4 people). The heater is used for the jacuzzi 99% of the time, and heats it up fast, about 1 degree/minute. The pool we only heat for special occasions -- probably takes about a degree/hour.
Do you need a seperate pump to pump water into the heater?
Paul P on May 22, 2019
BEST ANSWER: Yes, the heater is attached to your circulating filter pump. Water runs through the heater at all times but only heats when the auto thermostat turns it on.
What does cord and no cord mean?
A shopper on Jun 25, 2018
BEST ANSWER: I just noticed this email. No cord means you have to run electrical wires to the inside and make a connection. If it comes with a cord, it may have a plug to go directly into an outlet or just wires so that a connection can be made at the outside power source. Mine came with no plug.
Should I cover this heater in the winter months?
L M on Oct 23, 2016
BEST ANSWER: Depends on your climate conditions. I would say yes if it will be subjected to a lot of rain and/or snow in winter and also if subjected harsh sun in summer. The outside is plastic and I think could be harmed or weakened by adverse exposure. A simple lean-to cover would probably suffice.
i have 2" plumbing, can i just put a reducer on it?
A shopper on Jun 6, 2016
BEST ANSWER: I reduced mine with no problems.
How Many amps does this heater need?
A shopper on Jul 29, 2019
BEST ANSWER: 15 amps
Can this be converted to lp gas?
Brian H on Jul 20, 2019
I am at a high elevation. Will it work well at 6,100 ft elevation?
A shopper on May 26, 2019
BEST ANSWER: I am at almost Sea level, but I don't see why it wouldn't work at a higher elevation, as long as the Gas pressure in your area is if sufficient as per the specs. Of course because of the higher elevation, it might take a bit longer to heat as the temperatures would be lower.
Can this heater be used with a saltwater pool?
Phyllis C on May 22, 2019
BEST ANSWER: yes if installed correctly.
I am considering installing solar to run my pool equipment. How many watts does this heater draw?
Dan G on Jul 19, 2018
BEST ANSWER: Do not buy a Pentair. The warranty only lasts 90 days if you install it yourself. Find a better manufacturer that backs their heater against defects for at least a year.
What does with or without cord mean? What's the cord???
A shopper on Jan 21, 2018
BEST ANSWER: power cord to plug it in or without for direct power hookup.
I have a 20000 gallon in ground pool. Will it just take longer to heat? Is waiting longer the only issue?
A shopper on Dec 5, 2017
BEST ANSWER: Yes, the Mastertemp will take 2.5 times longer to heat the pool compared to a Mastertemp 400.
can I buy this Pentair gas pool heater through Home Depot?
A shopper on Aug 25, 2017
BEST ANSWER: Hello, we are not affiliated with Home Depot so we are not aware of the products that they sell. They may purchase Pentair products through us or you can order direct from the website or call our office and a sales rep will happily assist you. Thank you.
will this heat an above ground pool 5000 gallon?
sarah w on Aug 17, 2017
BEST ANSWER: for sure, we have a 10,000 gallon pool and heats just fine
I have an indoor therapy pool 8ft x 17ft does this brand operate in a confined space and come with a remote control or separate wire to control the unit?
A shopper on May 1, 2017
BEST ANSWER: Yes will operate in confined space as long as you VENT IT TO THE OUTSIDE.No remote control, on unit control only.Very happy with heater and this price is the best i found.
We just opened our pool and the heater would not work. So we opened the heater and found all the wires had been chewed to nothing. How can we keep this from happening again? Help
A shopper on Apr 16, 2016
BEST ANSWER: put the moth balls in the bottom of it
I had an electric heater. I am now just wanting a heater to heat my spa. in order to use this heater do i need to run a gas line?
A shopper on Jun 23, 2018
Can anyone confirm, I have ordered a master temp 125 propane, I am 45 feet away from my propane source, looks like half inch line for my supply?
jerry k on Jun 12, 2018
I have a pentair mastertemp 125 pool heater. I cannot get the unit to power up. The gas is hooked up, switch on. water is flowing through nicely. I plug in the unit and it jut will not power up. Am I missing a step?
A shopper on Jun 1, 2018
My above ground pool pumps 1,075 gallons an hour. Is this sufficient flow rate to ignite this heater? If not, what do I need to install or adjust?
Michele R on May 25, 2018
Do I need a professional to install?
Stephanie B on May 18, 2018
I have a 27' round 52" high pool, looking for a natural gas heater, but I'm not sure what I would need in BTU's?
Jan K on May 7, 2018
Would this heater work well for my 24' above ground round pool?
Z K on Apr 23, 2018
how to know how to buy correct heater for pool?
jjames r on Apr 23, 2018
Is this heater will be sefficent for my under ground pool. 18'foot24'foot×average hight 5' (rectangular)???
A shopper on Apr 15, 2018
what hookup/plumbing is included?
A shopper on Dec 31, 2017
4.2 / 5.0
9 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
Excellent.. Very happy with this purchase..Saved thousands$$$ !!!
I would recommend this product I saved atleast $2,000 with this purchase just by waiting a little longer for the heat which gets really hot .when friends are coming over at 6pm I just turn it on at 5pm that's the only difference with the more expensive heaters .Excellent Quality!!! just more wait time..very happy with my purchase!!!
September 9, 2016
over 3 years ago
Very good small heater
While talking with my pool guy, he recommended this small heater for my 10,000 gallon pool and its working like a champ, always happy with Pentair products and this was perfect for my needs.
October 1, 2016
Great purchase!
Good communication. Fast shipping. Most importantly, I am very pleased with my Mastertemp 125 so far.
August 22, 2016
over 3 years ago
Works as advertised
It's so nice to have a heater that just works. A must have for people in cold areas that want to still enjoy their pool.<br>
April 4, 2017
Purchased this heater on line, arrived in great condition, installed and have used it once to date. So far so good.
July 9, 2017
over 2 years ago
Works very well with my Endless Pool.
It heats the water (2500 gallons) by 3-4 degrees an hour which is quite quick for its size I would think. It is controlled poolside through the EP Gecko. Very satisfied.
October 23, 2016
over 3 years ago
Great cheap heater for a good price.
This little heater heats the water up much faster than expected, i would buy it again and would recommend it for a nice cheap spa heater.
December 14, 2018
9 months ago
It warmed my 13000 gallon pool 15 degrees in 12 hours.
May 26, 2019
4 months ago
The heater has a whistling vibration tone that our pool service hasn't been able to fix. It is very loud and disturbing. I am going to call your company on Monday. You can either tell me what to do or you can replace it.
Elizabeth Pease
June 2, 2018
1 year ago
Adobe Acrobat PDF Brochure
Adobe Acrobat PDF Owners Manual

How do I register for the warranty with my new Pentair product?
For Pentair's warranty registration information, and to submit online, please click here.  You can also access more information about Pentair by visiting our manufacturer page.

While the majority of Pentair products are covered by a 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 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.
^Labor Costs are not covered outside of US/Canada
Product/Product Category Length of Warranty Requires Professional Installation TradeGrade
SunTouch® Solar and SolarTouch® Control Systems 3 Years Yes  
Automation equipment, excluding SunTouch® Solar and SolarTouch®Control Systems 1 Year Yes  
IntelliConnect™ 1 Year Yes
IntelliCenter® 1 Year Yes
IntelliLevel™ 1 Year Yes
Filters 1 Year Yes  
MiniMax 75/100 1 Year Yes  
ETi™ 400 3 Years Parts & Labor^ Yes
UltraTemp ETi™ 3 Years Parts & Labor^ Yes
Heaters 2 Years Yes  
Heat Pumps
Heat Pumps 2 Years Parts & Labor^ Yes  
Compressor 10 Years Parts & Labor^ Yes  
Titanium Heat Exchanger Lifetime Yes  
Light Bulbs 60 Days Yes  
Lights 1 Year Yes  
IntelliBrite® 5G White LED Light 2 Years Yes  
MicroBrite™ 2 Years Yes
Single and Dual Speed Pumps 1 Year Yes  
Single-Phase, TEFC Super Duty Pumps 2 Years Yes
Select Variable Speed Pumps 3 Years    
SuperFlo® and SuperMax® VS Variable Speed Pumps 2 Years Yes  
IntelliFlo (#011028 and IntelliPro (#P6E6VS4H-209, #013028) 2 Years Yes  
IntelliFlo 2 VST (# 011055) and IntelliPro 2 VST (# 013001) 3 Years Yes
IntelliFlo VSF (# 011056) and IntelliFloXF VSF (# 022056) 3 Years Yes
IntelliPro VSF (# 013004) and IntelliProXF VSF (# 023056) 3 Years Yes
BioShield®UV Disinfection Sanitizer 2 Years Yes
BioShield Sanitizer Quartz Sleeve only 1 Year  
IntelliChlor®Salt Chlorine Generator (without Power Center) 2 Years    
iChlor™ Salt Chlorine Generator - Bundle with Power Supply and Cell (iChlor 15 and iChlor 30) 3 Years Yes
White Goods / Water Features / Valves
White Goods and Water Features and Valves 1 Year Yes  
Maintenance Equipment / Replacement Parts 60 Days (with exception of motors)    
Single-Phase, TEFC Super Duty Replacement Motors 2 Years Yes
Above Ground Systems
Above Ground Systems 1 Year    
Cleaners (Automatic cleaners purchased in the USA from entities outside the USA do not qualify for any warranty)
Tires, Rollers, Brushes, Climbing Rings, Cartridge Fillers Sixty (60) days    
Suction Seal, Foot Pad, Wings, Bumper, Strap, Seal Flaps 1 Year    
Legend and Legend II Inground Cleaner 1 Year    
Racer® Inground Cleaners 1 Year    
Platinum™ Inground Cleaner 1 Year    
Warrior® Inground Cleaner 2 Years    
Lil Rebel™ Aboveground Cleaner 2 Years  
Tires, Rollers, (Rebel, Warrior and Lil Rebel only) 90 days    
Dorado® Inground Cleaner 2 Years  
Kreepy Krauly® Inground Cleaner 2 Years    
Kruiser™ Inground Cleaner 2 Years    
Great White® Inground Cleaner 2 Years    
Racer LS® Inground Cleaner 2 Years  
Rebel® Inground Cleaner 2 Years  
SandShark™ Inground Cleaner 2 Years    
Prowler® 820 and Prowler 830 Inground Cleaners 2 Years    
Prowler® 910, 920 and Prowler 930 Inground Cleaners 2 Years  
ACU-TROL AK Color and Accessories 1 Year    
ACU-TROL Commercial Controllers 5 Years    
ACU-TROL Commercial pH or ORP Probes 2 Year    
ACU-TROL Electronic Modules 5 Year    
IntelliChem Commercial Chemical Controller 1 year^    
IntelliChlor (CIC60P & CIC60S) Commercial Salt Chlorine Generator (w/o power center) 2 Years or 15,000 operative hours (whichever comes first)    
Heaters 1 Year    
Heat Pumps 2 years parts & labor^    
Lights 1 Year    
STARK Commercial Filters 3 years^    
THS Series Commercial Filters 3 years^    
Max-E-ProXF Variable Speed Pump 2 years  
WhisperFloXF Variable Speed Pump 2 years  
Exceptions that may result in denial of a warranty claim:
  1. Damage caused by careless handling, improper repackaging, or shipping.
  2. Damage due to misapplication, misuse, abuse or failure to operate equipment as specified in the owner's manual.
  3. Damage caused by failure to install products as specified in the owner's manual.
  4. Damage due to unauthorized product modifications or failure to use Pentair original replacement parts.
  5. Damage caused by negligence, or failure to properly maintain products as specified in the owner's manual.
  6. Damage caused by failure to maintain water chemistry in conformity with the standards of the swimming pool industry for any length of time.
  7. Damage caused by water freezing inside the product.
  8. Accidental damage, fire, acts of God, or other circumstances outside the control of Pentair.
  9. Please see warranty card for commercial exceptions.
This information was updated on 6/17/19. For the most current information and full warranty policy please visit www.pentair.com.

 Adobe Acrobat PDF Warranty Information
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Pool Supply Unlimited is an e-commerce company that loves water. We love to pump it, filter it, heat it, chlorinate it, light it up and stare at it while we're barbequing a fat, juicy steak. There are real pool professionals working here. Our guys have seen thousands of pools in their careers, no exaggeration. We are based in Southern California and can land most products to your door (within the 48 contiguous states) in less than a week.
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