Purex Triton Minimax Plus 150M not staying lit

[codyt]

My pool heater has worked fairly well for the 11 years that I've owned it, but now I can't get it to stay lit.

Background: The heater came with the house/pool when I bought it out of foreclosure in 2012. I don't know any history on it before that, but it is old. In 2013 I wasn't getting enough voltage from the thermopile, so I replaced it and that took care of that problem. I also replaced the pressure switch in 2015.

The heater has worked fine until a month or so ago. I couldn't get the heater to fire up. I checked voltage, and was only getting about 190 millivolts. While trying to remove the thermopile, I accidently broke the pilot assembly. So I bought a new thermopile and pilot assembly. I am now able to get about 500 millivolts from the thermopile. But when I flip the switch to on (spa or pool), the furnace starts to fire and then goes out, and then the pilot is really weak looking. Below is a link showing what happens.

You can hear me flip the switch on at the 2 second mark. Then it begins to fire at the 13 second mark, but then immediately goes out.

Does anyone have any ideas on what the problem might be with the heater?


Thanks,
Cody

 

[ajw22]

Your heater propane or NG?

You check the static and dynamic gas pressures with a manometer?

@swamprat69 may have ideas.

 

[codyt]

Your heater propane or NG?

You check the static and dynamic gas pressures with a manometer?

@swamprat69 may have ideas.

My heater is natural gas.

I have not checked gas pressures.

 

[swamprat69]

All indications seem to point to a gas supply pressure problem. As Allen mentioned you should check both static and dynamic gas supply pressures as the heater attempts to fire up. New pilot assembly would seem to eliminate the possibility of a restricted pilot orifice and even then with the heater being a miilivolt system the thermopile output should not drop quickly enough to drop out the gas valve unless it was just on the edge of being viable to operate the system (but still a possibility). As mentioned both the pilot and main flame receding as the gas valve opens point to a gas supply pressure problem.

 

[codyt]

All indications seem to point to a gas supply pressure problem. As Allen mentioned you should check both static and dynamic gas supply pressures as the heater attempts to fire up. New pilot assembly would seem to eliminate the possibility of a restricted pilot orifice and even then with the heater being a miilivolt system the thermopile output should not drop quickly enough to drop out the gas valve unless it was just on the edge of being viable to operate the system (but still a possibility). As mentioned both the pilot and main flame receding as the gas valve opens point to a gas supply pressure problem.

Your heater propane or NG?

You check the static and dynamic gas pressures with a manometer?

@swamprat69 may have ideas.

Thanks for the responses. You led me down the correct path and now the heater is heating my pool. Turns out there was nothing wrong with the heater.

I don't have a manometer to check the pressure, but your posts made me think to try to fire up the furnace that sits right next to the pool heater. It would light it's pilot, but then when it tried to fire up, it would do the same thing the pool heater did. So that led me to believe that you were on the right track with the questions about gas pressure. I am currently finishing my basement, so I though maybe I had accidently partially closed a valve. I looked and all the valves I could find were still open. So I went outside and looked at my meter. On the outside of the meter, the clear plastic case was very pretty and fresh and new looking. There was a date (that looked like a manufactured on date) on the label of 4-17-2023. So I called the gas company and asked them when was the last time they serviced anything on my property. Turns out they installed a new meter in early August, which matches up with when my water started getting cooler. They came out and looked at the meter and said it was seized up and not letting gas through. They installed another new meter and now everything works again.

 

[1poolman1]

My pool heater has worked fairly well for the 11 years that I've owned it, but now I can't get it to stay lit.

Background: The heater came with the house/pool when I bought it out of foreclosure in 2012. I don't know any history on it before that, but it is old. In 2013 I wasn't getting enough voltage from the thermopile, so I replaced it and that took care of that problem. I also replaced the pressure switch in 2015.

The heater has worked fine until a month or so ago. I couldn't get the heater to fire up. I checked voltage, and was only getting about 190 millivolts. While trying to remove the thermopile, I accidently broke the pilot assembly. So I bought a new thermopile and pilot assembly. I am now able to get about 500 millivolts from the thermopile. But when I flip the switch to on (spa or pool), the furnace starts to fire and then goes out, and then the pilot is really weak looking. Below is a link showing what happens.

You can hear me flip the switch on at the 2 second mark. Then it begins to fire at the 13 second mark, but then immediately goes out.

Does anyone have any ideas on what the problem might be with the heater?


Thanks,
Cody

500mV is not enough to keep a millivolt heater firing. As soon as the main valve opens all the voltage is used up, main valve closes, and the heater goes out. You need a minimum of 600-650. Pilot valve takes 100mV, main valve takes 400-450. Then you need to have a reading of about 100 left over with the heater running to keep it running.