H350 Not Heating as Effective as it should

[cth6]

Fired up the pool heater and it is taking forever to heat the spa up. Usually 1 degree per 2 mins, right now running 1 degree per 6 mins. Cleaned the burner assembly and no change. The assembly was relatively clean for 6 years old.

11"wc at the 2nd stage propane regulator when heater off. Heater on 2"wc. That seems to be low.

0"wc at the gas switch inside the unit when off which is good and 2"wc when the heater is lit. I believe the manual says that it should be about 9"wc when heater running.

The fact that it is the same reading of the 2nd stage and the gas switch tells me that if there is an issue, it is at the 2nd stage regulator or with the first stage regulator.

Is 2"wc ok? Should I be testing something else? Thoughts on what the issue could be?

 

[JasonLion]

2"wc operating is too low. Something is restricting the gas flow somewhere along the line. Usually that is a sign of a bad pressure regulator, but it can also be water accumulating in the gas pipe or some other kind of obstruction. Of course this can also happen when you are running out of propane in the main tank.

 

[ps0303]

Are "seeing" gas coming out of the vent line for the second stage reg? You can usually see the vapors pretty good or if you put your hand up to the vent line you can feel the pressure of the gas. Also check to make sure you have gas in the tank as well.

 

[cth6]

Thanks for the replies. To close the loop on the issue. I pulled the second stage as I figured that had to be it. Behind the adjustment cover there was a white powder that looked like DE that was damp. I dissembled the 2nd stage and it was full of that white powder on the high pressure side. The main copper feed from the 1st stage was clean as was the vent pipe and the low pressure piping. Well the low pressure piping did have little white dots covering the inside of the first few inches that looked like a light coating of powder coat.

After replacing the second stage with an old one from a friends house, I was back in business. 12"wc when off and 10.5"wc when burner running. Went back to a degree every minute or so.

In hind sight, I am not sure if turning the gas off at the tank after use was causing this. I had not used the heater in almost 9 months. Usually when I turn the tank on, you can hear the first stage repressurize. I usually lose 5% of the tank per month if I leave it on. Guessing it is due to the heating and cooling during the summer months. Gets into the 90's then summer rain cools it down to the high 70's on a daily basis.

Hopefully this helps someone else.

 

[ps0303]

If you're losing gas like that then you probably have a leak somewhere and you should get it checked out. You shouldn't lose any gas no matter what.

 

[racket]

I don't think he's losing gas, but the regulator is not regulating properly.