Propane Test Question

[RaymondR]

Originally Posted by MCilenti

Mike,
The pressure gauge is upstream of the regulator...in other words, it's measuring high pressure, so the 'settling' is going from high pressure down, not the other way.
Cheers,
Mike

Yes, that is true but after pondering on it I realized that there is a very small trapped volume between the bottle shut off valve and the regulator and a comparatively large volume downstream of the regulator between it and the appliance. Consequently any bleed through from the high pressure side ie. where the gauge is, to the low side whilst the regulator settles would show a pressure drop on the high side.

In my opinion this is the most probable cause of the initial bleed off which then stabilizes and the test is valid.

[MikeHoncho]

Originally Posted by RaymondR

Yes, that is true but after pondering on it I realized that there is a very small trapped volume between the bottle shut off valve and the regulator and a comparatively large volume downstream of the regulator between it and the appliance. Consequently any bleed through from the high pressure side ie. where the gauge is, to the low side whilst the regulator settles would show a pressure drop on the high side.

In my opinion this is the most probable cause of the initial bleed off which then stabilizes and the test is valid.

Seems a poor place to put a pressure gauge given the characteristics of LPG. I’d put it down stream of the regulator to confirm proper function if I really had to have a gauge in the system. I hope it’s not there to be used for a lpg volume gauge for the tank.

[cal40john]

Originally Posted by MikeHoncho

Seems a poor place to put a pressure gauge given the characteristics of LPG. I’d put it down stream of the regulator to confirm proper function if I really had to have a gauge in the system. I hope it’s not there to be used for a lpg volume gauge for the tank.

The pressure gauge is to leak test the system. The pressure on the downstream side of the regulator is only 0.5 psi.

https://www.boatus.com/expert-advice...ropane-systems

[Bill O]

Originally Posted by MikeHoncho

Seems a poor place to put a pressure gauge given the characteristics of LPG. I’d put it down stream of the regulator to confirm proper function if I really had to have a gauge in the system.

Actually the gauge placement before the regulator is good to help detect regulator leaks, which do on occasion go bad. To test the full system one would need to leave the solenoid open and turn the bottle off to see if it holds pressure.

The only other place I would put it would be after the solenoid. This would help monitor/test the hose and connections to the propane appliance after the solenoid was shut down/turned off.

The article mentioned above the only way to test the fullness of the tank is to weigh it. While that may be the most accurate way, this isn't too feasible while on the boat. A simple lpg tank monitor (temp strip) taped to the side of metal tank is a good one to do on the boat (if you can easily see the side of the tank).

[RaymondR]

The problem with subjecting cooking appliances to the full bottle pressure is that it tends to invert the stem seals in the gas controls and cause them to seriously leak.

Had a friend who appeared one day with both hands swathed in bandages. Knowing his propensity for mishaps I asked his wife the cause and she said the stove. Also knowing that he had a fairly normal anglo-saxon male ego and that she had expressed severe frustration at living aboard without a cooking appliance I wandered over to their boat and took a look at the gas locker. The problem was that there was no regulator in the gas supply. The wife produced the integrated regulator/solenoid which he had exchanged for a solenoid only and I refitted it and found the original culprit electrical problem, straightened out the lid of the cooker, gave each valve a few pushes to de-invert the stem seals and advised my mate to abandon the gas system repairs business.

[MCilenti]

Ahoy Team,
I wanted to provide an update.

We took our oven off the mounts to install new mounts (I'll expand on this below). While it was off, I took the opportunity to soap test the flare fitting between the hose and the oven and found a VERY slight leak. I tightened it up and conducted the pressure test again with absolutely no pressure drop at all. Interesting to note that our propane sensor is immediately below this and the leak was so small, that it didn't detect it. Not sure if this was the original cause or if it started leaking when we moved the oven, but we'll keep conducting the pressure tests frequently.

Now...about our stove mounts. As I mentioned in the original post, we just completely replaced our propane system and that included the stove. We chose a Force 10 for several reasons, but one of the main ones was because it was the same model as our previous stove so we figured it would be a drop in replacement. Well...we had to move the mounts by 1/2 inch so it wouldn't hit the edge of the opening when it gimballed. Additionally, the mounts included weren't even shown in the directions. After installing the new mounts, the opening between was too small (contrary to the directions) for the stove. So, we used the mounts from the old stove, which fit.
However, I really wanted to use the new mounts for several reasons- notably a larger bearing surface for the pivots and better retention in the event of a rollover. So...we took off the wood spacer blocks we had and trimmed them so the new mounts would fit. However, there is a round head screw on the outside of the stove right where you need to mount the blocks. In other words, the tolerances for mounting the stove are extremely tight (i.e. you have about 1/8 inch slop). Either you are too tight and hit the screw heads with the mounts, or you are too wide and the stove won't fit in the mounts.

So...be aware for those contemplating a new stove! The instructions and dimensions found online at Force 10's website do NOT match those you receive with the new stove and you may need some modifications.

Thanks to all for the help and we'll keep you updated if anything changes.
Cheers,
Mike