20 Most Recent Hayward H Series Millivolt 250,000 Btu Pool Heater H2501 Questions & Answers

Having multiple issues with a milli-volt heater very common and can be expensive to fix at times. Start by cleaning EVERY connection in the safety circuit and the pilot circuit. If you have a milli-volt meter that would help a lot.

Hayward H Series... • Answered on Jul 24, 2017

since your question refers to two heaters 250000btu and h150, the best i can offer is the owners manual that covers both. there is no thermocouple on either but there is a manual thermostat, high limit sensors, thermostat etc. this manual will show where and how to change all of that http://www.hayward-pool.ca/pdf/manuals/Manual285.pdf

Hayward H Series... • Answered on Dec 20, 2015

Very simple... one complete bracket will drop straight down and then pull it out. two small fasteners hold it in place... one screw and one sm. nut. Located on the very bottom of inside of heater cabinet, Left side, below the burner tray. Nothin to take apart. Easy peasy. click the link to go to that page, where you will see a picture of the bracket with the igniter and flame sensor. You will see the stud where you will remove the nut, and you will be able to see the hole where the screw is supposed to be, both securing it to the burner tray. Hayward Ignitor Assembly with Bracket Series Heaters HAXIGN1931

Hayward H Series... • Answered on Apr 04, 2015

That is the same as a pilot generator. it is a thermal sensor right next to the pilot burner itself, it is touching the pilot flame. Its purpose... Is to get hot and then with that heat, it will generate voltage. But UNDER one volt. That is called Milli-volts. just enough power to be generated, to operate the switches and gas valve to open and close as needed! I had a customer tell me one time, that he wondered why there were so many wires in the heater, and the fact that he brought no power supply wires to the heater! And then I explained to him how his Milli volt system operated.

Hayward H Series... • Answered on Apr 04, 2015

Hi this is John the Hayward tech. If you have a millivolt heater it will only have one therm and an on and off switch. What you are describing is a electronic heater. Please call our tech line at 908-355-7995

Hayward H Series... • Answered on Sep 03, 2014

you need to replace either the display board or the main circ board

Hayward H Series... • Answered on Aug 28, 2014

On your main gas manifold you have orfaces that screw into it at each burner. Remove these and see if their are small spider webs in them. They will look like little lint balls. They can keep your main burner from getting gas and in turn keep the heater from sensing flame. The pilot lights and the heater starts but no flame at the main will shut it rite down. See if this helps.

Hayward H Series... • Answered on May 25, 2014

you prolly have an electrical short somewhere. follow the circuit and if any safety is getting around 200-250 dc millivolts then theres the problem. otherwise you have an open safety switch, or tsta controls

Hayward H Series... • Answered on Aug 07, 2013

Thank you for posting your question here on Fixya.com.

An IF error on a Hayward heater means the heater is not lighting; or it has lit but the control board does not recognize the burners are lighting and after a few attempts has locked itself out. It will reset itself and try again after 60 minutes or after power is interrupted and switched back on.

I'd start with determining if the heater is in fact lighting the burners or not. If it is the flame sensor is not sending the signal back to the board indicating such and needs to be looked at. If it is not lighting then you'll need to look at the control board, the gas valve and gas pressure to see if it is an electrical issue with the board or valve or there is a gas pressure issue in the supply line.

Depending on what you find you may want to seek professional help or add a comment to this post for further assistance.

You can also refer to your owner's manual, found here.

If this answer does not fix your problem, please comment with additional details prior to rating the answer. You may also contact me thru our website at www.arrowpools.net. Positive feedback is appreciated once your problem is solved!

Hayward H Series... • Answered on Aug 26, 2011

Check the disc and shaft on the by-pass, then check to see if you have an external by-pass and be sure it is closed if you have one, then adjust it open a small amount.

Hayward H Series... • Answered on Aug 15, 2011

Your are on the right track. Before you write off the gas control valve I would at least replace the thermocouple. See this picture:
The thermocouple is located in between the ignitor and the bracket. It has a braided umbilical with 2 terminals that connect to the Gas control valve. If there is not a Milli-volt signal to the gas valve when a flame is present the gas valve will shut off the gas to the burner. You DO NOT have to replace this whole $108.00 assembly. You can just replace the Thermocouple only. The manual below does NOT show just the thermocouple but most any pool & spa dealer will have this thermocouple in stock.

The manual is here:

Thanks for choosing FixYa,

Hayward H Series... • Answered on Jun 09, 2011

The solenoid inside the gas valve, the part that is supposed to assume the pilot light once the thermocouple is hot, is failing. You need a new gas valve. Your part number is HAXGSV0001 for natural gas or HAXGSVS0003 for propane.


Hayward H Series... • Answered on Jun 07, 2011

Not finding what you are looking for?
Hayward H Series Millivolt 250,000 Btu Pool Heater  H2501 Logo

Popular Tags

53 questions posted

Ask a Question

Usually answered in minutes!

Top Hayward Pool & Spa Experts

john h

Level 3 Expert

23796 Answers


Level 3 Expert

85239 Answers

Paul Carew

Level 3 Expert

3538 Answers

Are you a Hayward Pool and Spa Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

View Most Popular

Hayward Pool & Spa

  • Hayward Pool & Spa

Most Popular Question

f error code

  • Pool & Spa