Pentair Mastertemp 250 screaming/whining on ignite

[Ahultin]

The propane tank is less than 20 feet from my heater and the regulator sits between the propane tank itself and the 3/4" black iron gas pipe I installed.

Sounds like you are good there just keep in mind it is effective distance so the 20ft plus risers plus 5ft for every fitting (tee's/ell's/union's/valve). You don't want to be chasing aa heater problem if it's really a supply problem.

 

[swamprat69]

Frontside and backside are not proper nomenclature for regulators and gas valves, so it is hard to tell exactly what you are talking about (frontside/backside???). The regulator and gas valve are designated with "inlet" and "outlet". The proper hookup of the manometer to the gas valve to check supply pressure (negative pressure in this case) to the heater is shown on page 19 of the manual https://www.pentair.com/content/dam...p/manual/Manual-MasterTemp-472592-English.pdf . The inlet pressure range for the gas valve is shown on page 20. You only need the positive side of the differential manometer to check if the inlet pressure drops out of range with the heater firing or the static pressure if the heater is not firing for either the gas valve or inline regulator. You should not be adjusting the gas valve regulator without having the manometer hooked as shown on page 19 of the manual. If you are listing adjustments to gas pressure you need to show both the original pressure readings and the readings that the pressure was adjusted to. Static pressure refers to the pressure without the heater firing and dynamic pressure refers to the pressure with the heater firing.

 

[johnsonps08]

Frontside and backside are not proper nomenclature for regulators and gas valves, so it is hard to tell exactly what you are talking about (frontside/backside???). The regulator and gas valve are designated with "inlet" and "outlet". The proper hookup of the manometer to the gas valve to check supply pressure (negative pressure in this case) to the heater is shown on page 19 of the manual https://www.pentair.com/content/dam...p/manual/Manual-MasterTemp-472592-English.pdf . The inlet pressure range for the gas valve is shown on page 20. You only need the positive side of the differential manometer to check if the inlet pressure drops out of range with the heater firing or the static pressure if the heater is not firing for either the gas valve or inline regulator. You should not be adjusting the gas valve regulator without having the manometer hooked as shown on page 19 of the manual. If you are listing adjustments to gas pressure you need to show both the original pressure readings and the readings that the pressure was adjusted to. Static pressure refers to the pressure without the heater firing and dynamic pressure refers to the pressure with the heater firing.

Sorry for the poor wording. I was referring to front side as the side facing out of the machine, so the inlet.

So to restate what I experienced:
- static pressure at the inlet was 10-11" WC.
- once heater fired, it dropped to just >8".
- differential pressure tested on the outlet waiverd a bit but never fell outside of the -.2 +/- .1 that the manual states.

Even with all the above, I was still getting the terrible squeal/whine. Only thing to stop it was putting my hand over the intake, as I showed with previous video UNTIL I decided to mess with the valve.

Wanted to make sure to say that I really appreciate everyone's help so far. But does anyone have an idea of what next troubleshooting steps they would take given all the above?

 

[Ahultin]

What size propane tank? To get sufficient vaporization to supply the 250k BTU's, it appears you need a 200 gallon plus tank (depending on average ambient temp during usage, lower temp, bigger tank)

 

[johnsonps08]

What size propane tank? To get sufficient vaporization to supply the 250k BTU's, it appears you need a 200 gallon plus tank (depending on average ambient temp during usage, lower temp, bigger tank)

Its a 120 gallon tank. I'm really out of my depth here so I apologize for the noob question but Is there a simple explanation for why the tank size would matter for a two-stage propane system? Would a 200 gallon tank not be able to run when the propane went <100 gallons of fuel?

 

[Ahultin]

Lol! No worries, we are on the outside edge of my understanding as well so maybe one of the experts will step in. Tank size, tank fill and temperature all play into the vaporization rate of propane. In most home applications this is rarely an issue but a pool heater is an extreme use case. Prior to the pool, my highest use appliance (also a high use case) was my tankless water heater at 196k btu's. The big difference though as I understand it is that my tankless water heater is throttled based on demand so it will rarely if ever reach that 196k btu demand. The pool heater on the other hand is all or nothing. When you call for heat on your mt250, it is using 250k btu's. The tank needs to have sufficient area to vaporize (boil) the liquid propane into enough gas to supply the heater.

LP TANK SIZING - Orion Propane Services

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