Propane Tank Noise when heating hot-tub.

Pesh

Member
Apr 19, 2020
10
Austin, TX
It has been quite a while now, but we’ve noticed that our propane tank makes a funny noise when the Spa heater kicks on. I have a video showing the noise but I could not attach it. The noise doesn’t happen when we first turn on the hot tub heater, its virtually silent. The sound occurs after the heater has been running for a while.

The heater (Pentair MasterTemp 400) works fine and the hottub gets to temp without issue. The sound only happens when the heater is running keeping the water at temp.

I assume this is not normal. Any idea what might be wrong?

Thanks in advance.
 

JamesW

TFP Expert
Mar 2, 2011
20,731
Post on Youtube and link.

What size is the tank and how full is it?

Are you getting frost on the tank?
 

JamesW

TFP Expert
Mar 2, 2011
20,731
The liquid propane in the tank needs to boil to convert from liquid to gas just like a pot of water on the stove boiling.

The liquid that boils absorbs heat from the rest of the liquid propane, which absorbs heat from the tank, which absorbs heat from the air.

During the process, the tank and valves can get cold enough that water in the air will condense and freeze.

This happens when the amount of liquid propane in contact with the tank is insufficient to provide enough heat.

Maybe contact the propane supplier to see if you should upgrade to a bigger tank or if any of the components need to be replaced.

Make sure that the valves, regulators, piping etc. are all big enough to carry the 400,000 btu/hr required. Undersized components can lead to issues.

Make sure that the regulators have the correct pressure and volume ratings.

When was the system installed?

Has the problem been the same since installation or has it changed over time?

Does the amount of liquid in the tank affect the noise?
 
Last edited:

Crabcruncher

Member
May 9, 2018
16
Panama city beach Fl.
It has been quite a while now, but we’ve noticed that our propane tank makes a funny noise when the Spa heater kicks on. I have a video showing the noise but I could not attach it. The noise doesn’t happen when we first turn on the hot tub heater, its virtually silent. The sound occurs after the heater has been running for a while.

The heater (Pentair MasterTemp 400) works fine and the hottub gets to temp without issue. The sound only happens when the heater is running keeping the water at temp.

I assume this is not normal. Any idea what might be wrong?

Thanks in advance.
If the noise sounds like a horn blaring, it is going to be the propane tank pressure regulator that sits on top of the tank. There are rubber diaphragms inside that need servicing. Most propane suppliers do not fix these reguators, they just replace them.
If you are renting the tank, call the propane company and tell them the regulator is making a noise loud enough to wake the neighborhood up.
 

Flying Tivo

Well-known member
Jan 24, 2017
1,889
Monterrey, NL, Mexico
Wow, certainly not normal. What i did is run a straight line without a regulator to the heater(1"). Then install the regulator besides the heater. Maybe this can help to alleviate the noise
 

Pesh

Member
Apr 19, 2020
10
Austin, TX
Yes, the noise seems to be coming from the tank. Our heater is 12 - 15' below the pool. I took the video from the pool. The propane tank + regulator have been there for 20 years or so.

The regulator is a Sherwood 800HPS1. From what I can tell it reduces the pressure to 10PSI and is configurable to a range of 5 - 15 psi. I couldn't tell you what its set at. I wonder if the regulator needs to be replaced?
 

Crabcruncher

Member
May 9, 2018
16
Panama city beach Fl.
When the tank is making that noise, go over to tank and put your thumb over the regulators vent opening, its that horn shaped part with the screen inside. The noise may stop for a while. The regulator needs replacing. If you rent the tank from the gas company, they are responsible for replacing it at no cost to you.
 
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