What kind of propane regulator to use?

Feb 10, 2004
4,060
Hunter 40.5 Warwick, RI
I have discovered that my propane regulator is leaking. So I ended up at a RV dealer and bought a regulator that "looks" like the OEM that is leaking. It is a single-stage regulator, and I cannot find any specification for the OEM unit. I also cannot identify its manufacturer.
I have read (and now cannot find the source) that only two-stage regulators should be used on boats and RV's. The OEM regulator pictured below does not look like any two-stage regulator that I can find. So I am wondering what does everyone else have for a regulator?

The next problem that I have is that after installing the new regulator and connecting to my propane tank, the high-side pressure is 160psi. Normally my propane pressure has always been about 90-100psi. My 10# tank has about 8# of propane. However the tank was in the 90 degree sun and I think the high pressure was due to this temperature. So I cooled the tank with cold water and the pressure went down to 130psi - lower, but still not at typical pressure. The new regulator claims to handle up to 250psi input.
However when I attempted to light my stove, a lot of gas was blown under the cook-top and flames were coming out at several openings. I shut the gas down immediately. According to the manufacturer of the new regulator, it is set to the standard 11" water column pressure. But the spec on the regulator claims 250psi max.
I am unsure as how to proceed. I have no way to verify the output pressure of the regulator. All of the two-stage regulators that I see are much longer in length and will not fit into my propane compartment without re-configuring the hoses and gauge fittings.

So, despite the requirement of a two-stage regulator, maybe the OEM is a one-stage unit. But I still have the problem of apparently having too much gas going into my stove.

Help anyone?
Rich

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jviss

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Feb 5, 2004
7,089
Tartan 3800 20 Westport, MA
Googled it:

"The pressure in a liquefied petroleum gas (LPG) tank, also known as a propane tank, can range from 100–200 pounds per square inch (psi). The pressure depends on the temperature, and can fluctuate slightly. For example, a 20-pound propane tank at 70°F might have 145 psi, but the same tank at 100°F might have 172 psi. The pressure can also be higher if the tank gets hot in the sun."
 
Feb 10, 2004
4,060
Hunter 40.5 Warwick, RI
@JoeWhite - It looks like you installed a single stage regulator like the original. The original regulator that you replaced is the same manufacturer and model as my OEM. Do you know the manufacturer or the specs of that original regulator?
BTW, very nice website.
 
Mar 6, 2008
1,221
Catalina 1999 C36 MKII #1787 Coyote Point Marina, CA.
Rich, I have listed the mfg in the text
Here is a copy of that text.

The regulator is Dickinson, Low Pressure Regulator part no 78177 for $ 15.69. I also ordered the Tank Fitting part no 318548 for $ 18.10. It included an elbow that I did not use. Instead I baught an elbow from Home Depot for $ 4.85 and teflon tape for $ 2.95.

View the album as well
Visit here for specs
 
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Jan 1, 2006
7,349
Slickcraft 26 Sailfish
When my regulator on my H356 failed I went to considerable trouble to get the drop in replacement, i.e. the exact same unit. I found it by tracking from the manufacturer to a local distributor. If I remember it was a welding supply or hydraulic supplier or both. But it went in with no space issues. There were no problems with supply fittings. And I could close the locker. In other words, it was worth the effort.
Did I mention that when I had to replace the fresh water pump on another boat the exact drop in wasn't available. For some reason the manufacturer felt making it about a 1/4 inch larger was OK. I had to chisel out some plywood on the cover to get it to seat. Of course it was also a bunk so .... standing proud wasn't an option.
 
Feb 10, 2004
4,060
Hunter 40.5 Warwick, RI
Rich, I have listed the mfg in the text
Here is a copy of that text.

The regulator is Dickinson, Low Pressure Regulator part no 78177 for $ 15.69. I also ordered the Tank Fitting part no 318548 for $ 18.10. It included an elbow that I did not use. Instead I baught an elbow from Home Depot for $ 4.85 and teflon tape for $ 2.95.

View the album as well
Visit here for specs
Joe,

I saw those notes. But I want the manufacturer and specs for the ORIGINAL regulator. It is a model 300, but I can't find the manufacturer or specs.
 
Mar 6, 2008
1,221
Catalina 1999 C36 MKII #1787 Coyote Point Marina, CA.
Oops, I goofed. Unfortunately I have discarded it.
It was on 1999 catalina 36 mkii. I wonder if they have any records.
 
Mar 6, 2008
1,221
Catalina 1999 C36 MKII #1787 Coyote Point Marina, CA.
This is the best photo from the album with mfg name on it. It appears to be TPA model 300.
Zoom in to see the name.
The gauge varies from 120 to 90 psi.


1724897743414.png
 
Jan 4, 2006
6,932
Hunter 310 West Vancouver, B.C.
the high-side pressure is 160psi. Normally my propane pressure has always been about 90-100psi.
The pressure produced by the liquid propane in the tank is in perfect lock step with its temperature, right down to the umpteenth decimal place :

1724890516242.png


This remains true right down to the last drop of liquid propane and assumes that the propane is 100% pure. Once all of the liquid has boiled off, you are down to the old PV=nRT gas law. As a matter of fact, the day you saw 160 PSI, the temperature of the liquid in the tank was, as near as I can see being blind in one eye and can't see out of the other, 34°C otherwise known as 93.2°F. Isn't that a little warm for your neighbourhood ? Never been there, so how would I know ?

A two stage reg. is always recommended for an application when the incoming pressure to the reg. is all over the place depending on the outdoor temperature. Now, having said that, I see yours, mine and the guy next door all have single stage regulators so let's deal with that.

You can measure the downstream pressure of the reg. by attaching a home made manometer partially filled with room temperature water, and made from cheap vinyl tubing of whatever dia. you have on hand. Something around 1/4" I.D. would be nice :

1724906240258.png


P2 is the reduced gas pressure and P1 is atmospheric pressure. If the reg. is working correctly "h" will be 11" on the tape measure. Don't worry about zeroing the tape measure when you have atmospheric pressure on both P1 and P1. Just pressurize and measure the difference between the levels in the two columns.

Jury rig the gas connections any way that works for you. Have the U tube assembly nailed to a small sheet of plywood and fixed near the propane tank, in the outdoors, and the tank shut off valve is always immediately at hand. This is not exactly according to Hoyle or Rube Goldberg when dealing with propane but if you are at all handy with your hands (which you have shown yourself to be) there is nothing here which will cause a problem.

- ALWAYS close the shut off valve if you step away from the equipment

- Use fire prevention common sense.

- No temporary propane fittings allowed inside the cabin.

- All propane open discharge must be in small quantities and be in the open cockpit.

- Ensure you are not in the doldrums while working with gas in the cockpit.

- Close the access which leads from the cockpit into the cabin.

- All propane fittings must be returned to their original gas tight condition before leaving the boat.
 
Jan 4, 2006
6,932
Hunter 310 West Vancouver, B.C.
For example, a 20-pound propane tank at 70°F might have 145 psi, but the same tank at 100°F might have 172 psi.
@jviss , I don't know who the author of this little gem is but I assure you, he's way past his re-test date

Look at the press. vs. temp. chart in post #11 and you'll find that contained liquid propane at a temperature of 70°F has a pressure of 110 PSI and not 145 PSI.
 
Sep 11, 2011
406
Hunter 41AC Bayfield WI, Lake Superior
Rich:

Under the plastic cap is a screw that can be used to reduce the out put pressure to the stove.
 
Feb 10, 2004
4,060
Hunter 40.5 Warwick, RI
The pressure produced by the liquid propane in the tank is in perfect lock step with its temperature, right down to the umpteenth decimal place :
<snip>
Thanks @Ralph Johnstone for your pressure vs temp graph. Actually my tank was in the sun and the temperature was about 90 degrees, so a pressure of 160 psi agrees with the chart.
Last night, just before sleep, I realized that I could construct the manometer that you describe. I just need to get some tubing and a fitting or two. I will probably do that since I am completely out of ideas on how to proceed.
 
Feb 10, 2004
4,060
Hunter 40.5 Warwick, RI
Rich:

Under the plastic cap is a screw that can be used to reduce the out put pressure to the stove.
I do know that, but I am reluctant to change the setting unless I can be sure that it is incorrect. And I do not know the range of setting that is possible.
 
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Jun 8, 2004
1,044
C&C Frigate 36 St. Margarets Bay, Nova Scotia
...However when I attempted to light my stove, a lot of gas was blown under the cook-top and flames were coming out at several openings. I shut the gas down immediately.
I do know that, but I am reluctant to change the setting unless I can be sure that it is incorrect.
If you have problems lighting your stove and "flames coming out at several openings" I think you can assume that your new regulator is incorrectly set. Try using the screw under the black cap to lower the pressure (by turning it anti-clockwise), and try lighting the stove again. Adjust the regulator until you have the range of flame you want on your burner, from simmer to high. Or use the manometer check suggested above. If you don't feel confident doing either of these things, call in a pro.
 
Feb 10, 2004
4,060
Hunter 40.5 Warwick, RI
This is the best photo from the album with mfg name on it. It appears to be TPA model 300.
Zoom in to see the name.
The gauge varies from 120 to 90 psi.
I managed to trace the OEM regulator to TPA Engineering Ltd to a company in the UK. Unfortunately, they are out of business, so I don't see a way to get the specs.
 
Dec 4, 2023
132
Hunter 44 Portsmouth
I managed to trace the OEM regulator to TPA Engineering Ltd to a company in the UK. Unfortunately, they are out of business, so I don't see a way to get the specs.
Hi Rich,

Do you have a place that re-certifies/services propane tanks near you? You might consider giving them a call and asking if they can test that regulator for you. I believe that some shops have a simple setup where they can measure input pressure and output pressure using compressed air to test if the regulator is working correctly.

You may also consider just buying a unit offered from a reputable marine retailer, like Defender or Dickinson if you're in doubt about the regulator you're using now.
Low Pressure Regulator - Single Stage

I think you might be going too hard on yourself by trying to source a regulator from the exact manufacturer, who you state is out of business. If you have the manual or specs on your stove, it would probably serve you to double check that the stove is designed to run on a common low pressure regulator (11" H2O as stated previously).

Personal experience: I've had both single-stage and two-stage regulators. I upgraded to the two-stage regulator when I installed a Dickinson propane stove (at that point I was feeding two propane appliances, so the two-stage regulator is required). Both regulators worked well.

PS - Since you mentioned that you "have gas leaking from several locations", you might also consider doing a leak down test after you have the regulator situation handled. It's very easy. There's lots of sources on the net that describe the test, if you haven't done one before.
 
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Feb 10, 2004
4,060
Hunter 40.5 Warwick, RI
Comments/answers are in the quoted text-


Hi Rich,

Do you have a place that re-certifies/services propane tanks near you? You might consider giving them a call and asking if they can test that regulator for you. I believe that some shops have a simple setup where they can measure input pressure and output pressure using compressed air to test if the regulator is working correctly.
I have searched the Warick, RI area for a propane service shop and come up empty. None of the propane dealers could offer any suggestions that panned out. If I was home (150 miles away) I have an excellent service shop that could help me.
You may also consider just buying a unit offered from a reputable marine retailer, like Defender or Dickinson if you're in doubt about the regulator you're using now.
Low Pressure Regulator - Single Stage

I think you might be going too hard on yourself by trying to source a regulator from the exact manufacturer, who you state is out of business. If you have the manual or specs on your stove, it would probably serve you to double check that the stove is designed to run on a common low pressure regulator (11" H2O as stated previously).
The stove manual (Seaward Model 3172) does not specify the type of regulator (single or double). It does spec the input pressure of 11" water column. The OEM regulator, which I have confirmed is leaking, is clearly a single stage type.

Regarding the new regulator that I have purchased, I performed a water column test per @Ralph Johnstone in post #11. I tested with a 1# propane tank and my 10# boat tank. The results showed that with an input pressure of 10 psi to 145 psi the output pressure was between 10.5" and 12.5" water column. The results varied a bit on multiple tests, and so did the temperature of the tanks vary during testing. Bottom line, I believe that the regulator is fine and is calibrated correctly.


Personal experience: I've had both single-stage and two-stage regulators. I upgraded to the two-stage regulator when I installed a Dickinson propane stove (at that point I was feeding two propane appliances, so the two-stage regulator is required). Both regulators worked well.

PS - Since you mentioned that you "have gas leaking from several locations", you might also consider doing a leak down test after you have the regulator situation handled. It's very easy. There's lots of sources on the net that describe the test, if you haven't done one before.
I did a leak down test on just the boat tank, gauge, regulator, and hose up to the solenoid valve. It held steady for over 5 minutes at 124psi input pressure.
The next leak test I did was with the stove burners and oven shut off, but with the solenoid valve turn on. At this point, the input pressure gauge read 0 psi, and my propane alarm inside the salon went off. This indicates a propane leak that is inside the boat.
I am confused as to why the input pressure gauge read 0 psi, and I am going to see if it also reads 0 psi if I disconnect the hose to the solenoid valve and let it vent to the atmosphere. Maybe this will give me a clue as to what is happening.


UPDATE: I disconnected the hose after the regulator that connects to the solenoid valve, and directing this hose overboard, I opened the valve on the propane tank. The input pressure read 0 psi and I could feel a slight supply of gas from the end of the hose. If I put my finger over the end of the hose, the flow decreased and the input pressure gauge increased to about 100 psi. So I can't really explain this scenario, but it agrees with the observation with everything connected to my stove.

My conclusion after this is that I have another leak somewhere between the solenoid valve output and the stove, or in the stove itself. I will now wait to get my air compressor and I'll pressurize the system and try to locate the leak inside of the boat.
END UPDATE

Meanwhile, I have a sailing buddy who is going to pick up my air compressor and hose at my home and bring it to me. I plan to connect it to the regulator input and try to find the leak in the salon. That will probably be tomorrow.

I am frazzled. First I discover the OEM regulator to be leaking. I confirmed this by installing it (heard leak) and then replacing it with the new regulator (no leak heard, and subsequent pressure leak down test confirmed). Now I seem to have leak somewhere in the salon near or in the stove. This is day four of dealing with this problem, and I have found that the most difficult problems are those where there are multiple failures. Maybe that is what is happening here.

See the picture below for my home-made manometer setup.

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