Capping a pigtail...

[Christhecaravanner84]

I have an auto changeover propane valve . Today I suspected one of my cylinders was empty as my water heater was on a red light and not working. Having checked my cyclinders, one of them is showing as nearly empty on the built in gauge , but still producing gas. Not sure why this particular cylinder has been used up because I have been trying to use up the smaller 3.9 so I can swap it for a 6, Maybe I have been turning the other one on first and it's been failing over to that one... Anyhow, It's got me thinking about what happens when I do need to take a cylinder out and I've got the fridge on gas. It just didn't seem right to leave one pigtail disconnected. Indeed, when I disconnected the bottle to give a it a bit of a slosh about , it did smell a bit gassy around the pig tail end. Having read up a bit on these, I understand now that if you disconnect one cylinder, you are relying on the non return valve to stop the gas flow, not good apparenly some low pressure gas can get through them, I am looking for some kind of blanking cap which would either go on the end of the pigtail or on the valve it's self. It rather seems to partially defeat the point of the changeover valve if I can't leave one cyclinder on whilst I take the other to exchange. And going by the "adventures" I had last time I wanted to buy a 6kg cylinder, it's not like I'll be just turning the fridge off for half hour. This is an item which I've convinced myself must exist. I'm either not looking in the right places or not doing the right search terms. I'm hoping one of you good folk can advise me. Thanks in anticipation!

By the way water heater working again after good old "turn it off and on". I did run my battery quite low and I've been using my generator on and off so I'm putting down to an electrical blip for now.

 

[ProfJohnL]

If you have a change over valve that does not seal an open feed you must get it repaired or replaced as it represents an unsafe gas system.

 

[Ern]

The smell from an open gas hose is quite normal, especially the Truma ones. It is probably the mixture of contaminants found in most gas hoses.

 

[Jcloughie]

I have an auto changeover propane valve . Today I suspected one of my cylinders was empty as my water heater was on a red light and not working. Having checked my cyclinders, one of them is showing as nearly empty on the built in gauge , but still producing gas. Not sure why this particular cylinder has been used up because I have been trying to use up the smaller 3.9 so I can swap it for a 6, Maybe I have been turning the other one on first and it's been failing over to that one... Anyhow, It's got me thinking about what happens when I do need to take a cylinder out and I've got the fridge on gas. It just didn't seem right to leave one pigtail disconnected. Indeed, when I disconnected the bottle to give a it a bit of a slosh about , it did smell a bit gassy around the pig tail end. Having read up a bit on these, I understand now that if you disconnect one cylinder, you are relying on the non return valve to stop the gas flow, not good apparenly some low pressure gas can get through them, I am looking for some kind of blanking cap which would either go on the end of the pigtail or on the valve it's self. It rather seems to partially defeat the point of the changeover valve if I can't leave one cyclinder on whilst I take the other to exchange. And going by the "adventures" I had last time I wanted to buy a 6kg cylinder, it's not like I'll be just turning the fridge off for half hour. This is an item which I've convinced myself must exist. I'm either not looking in the right places or not doing the right search terms. I'm hoping one of you good folk can advise me. Thanks in anticipation!

By the way water heater working again after good old "turn it off and on". I did run my battery quite low and I've been using my generator on and off so I'm putting down to an electrical blip for now.

I get your point and it is a concern if the auto valve might fail. And how would you know that is has or might fail. It is not something I have thought about, assuming they are made fail safe. Also, it is not something I have found to be a problem.

I have had auto valves on my last few vans and simply don't use them. This is because I want to know when a bottle is empty which gives me time to get a replacement. Easier than checking the bottle weights or relying on the guages.

However, if you are relying on gas for heating overnight an auto changeover might be useful.


John

 

[Christhecaravanner84]

I get your point and it is a concern if the auto valve might fail. And how would you know that is has or might fail. It is not something I have thought about, assuming they are made fail safe. Also, it is not something I have found to be a problem.

I have had auto valves on my last few vans and simply don't use them. This is because I want to know when a bottle is empty which gives me time to get a replacement. Easier than checking the bottle weights or relying on the guages.

However, if you are relying on gas for heating overnight an auto changeover might be useful.


John

The other thing is, if you are running the fridge on gas and a cylinder runs out while you are out. Ive tested switching the valve whilst the fridge is going and the new supply starts before the thermocouple cuts out, so thats reassuring. It must be possible to get something to blank off the pipe just for reassurance.

 

[RogerL]

The changeover valve will (probably) have come with a blanking cap for an unused connection - but that requires disconnecting the unused pigtail from the changeover valve.

 

[Damian]

If the non return valve in a pigtail fails you will certainly know about it as you will have an open gas pipe pumping out gas at 30Mb.
When dealing with any gas connections you almost always get a residual smell of gas from the joint.

As far as I am aware there is no blanking cap for any of the pigtails.

 

[Jcloughie]

If the non return valve in a pigtail fails you will certainly know about it as you will have an open gas pipe pumping out gas at 30Mb.
When dealing with any gas connections you almost always get a residual smell of gas from the joint.

As far as I am aware there is no blanking cap for any of the pigtails.

Is the non return valve in the pigtail or in the valve mechanism?

John

 

[Damian]

The non return valve is in the pigtail

 

[Jcloughie]

The non return valve is in the pigtail

Thanks, I was not aware of that.

John

 

[Mandarin]

Feom new our can came with a changeover valve but only one pigtail. Apparently the reason is that MIRO is calculated with as many gas bottles as pigtails.

Anyway the relevance is that the unused hose connector was blanked off with a flimsy plastic push on cap, clearly designed to just keep dust out. So the changeover valve must be expected to not leak via the unused side. If it is leaking then I would say it needs replacement

I suspect most of us with these has the gas connected to one cylinder whilst the other is in the car being changed.