Hayward H250 heater issue

Jump to latest Follow Reply
R

Ryanrobert

Member
May 6, 2022
15
Oshawa
Hey all, I'm having an issue with my heater. It's an older model h250 millivolt system. The heater will fire up, and after about 45 seconds to 1 minute it will go off and the pilot light extinguishes.

Anyone run into this issue and solve it?

Thanks in advance!
 
Welcome to TFP.

Sounds like a bad thermopile not sensing the flame.

From Hayward H-Series Heaters - Further Reading

Normal sequence for lighting the millivolt (MV) pilot would be to turn the gas valve knob to the "pilot" position and push it down to allow gas flow to the pilot. While holding the gas valve knob down, push the piezoelectric " spark generator" button multiple times until you observe a pilot flame.[5]

Keep holding the gas valve knob down for about 2 minutes. At this time ( after 2 minutes ) you can use a multimeter to measures the output of the thermopile in DC millivolts (the part that sits in the pilot flame and has 2 electrical leads attached to the gas valve ). It should measure 325 MV or above with no load. If it doesn't measure 325 MV or above, replace the thermopile.

@swamprat69
 
Bad millivolt generator (thermopile, etc.) usually. They are rated at 750mv. A new one, after it has been heated a while will generally produce about 700. After the heater lights an output of at least 100 still needs be seen on a meter or the heater will shut down. Get a universal fit model as it will have the correct bushings to fit most pilot burners.
Another thing to consider is that most pilot burners have a small diverter above the flame to make sure the flame contacts the generator near the middle. If that is gone it will also cause this issue and you will be very hard pressed to get a new burner.
 
Do you have a multi-meter that will read millivolts? The control circuit in a millivolt system is one continuous series loop through which a very small voltage passes. Any resistance within that loop from dirty/corroded physical or internal contacts can cause enough of a voltage drop that the gas valve will drop out when load (main gas valve) is applied. You can check the voltage (millivolts) at the gas valve while the heater starts up to see if this is happening. You can also check for an excessive voltage drop across either external or internal contacts individually within the series loop to isolate a problem to a specific point. It wouldn't hurt to clean all external contacts in the loop and confirm that the pilot flame is not weak due to a dirty pilot orifice.
 

Enjoying this content?

Support TFP with a donation.

Give Support
If a heater is used regularly, 10 years is a good life. On a commercial property manufactuers will tell you, though not very loudly, that 5 years is a good life. That has been my experience. Internal temperature of the firebox is about 2000f (1090C). They operate under the harshest of conditions, especially in your climate. If the weather doesn't get them they cook themselves to oblivion. Didn't notice your location at first.
Click to expand...
 
1poolman1 said:
Natural gas millivolt heaters have been illegal for 30 years.
Click to expand...
Millivolt heaters are still legal in some places.


www.doheny.com

Raypak Model 206A Millivolt Natural Gas, 199,500 BTU

Raypak Model 206A Millivolt Natural Gas, 199,500 BTU. Hurry and purchase today at Doheny's Pool Supplies Fast
www.doheny.com www.doheny.com

Digital vs Millivolt Pool Heaters – Raypak

Raypak Pool & Spa, Residential and Commercial Hydronic Products -
www.raypak.com www.raypak.com

In addition, millivolt ignition is no longer allowed with natural gas in certain areas (such as California) because of concerns about fuel usage when the unit is not firing.
Click to expand...
 
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply