Cause and effect?

[Cummins12V98]

Recently I filled my large outer propane tank. When re connection I heard a hiss and determined the crimp was leaking for the large connector. I found Mr heater hose in 12" but when looking at the end that screws into the transfer device it did not have a check valve as the OE did. I looked a few places and finally stopped at a Propane Delivery Company that had parts also. The Manager said no need for the check valve. OK so I installed the hose and all seemed well.....UNTIL.

We stayed at a rest area last night on our trip South and it was COLD up near Barstow, CA. I fired the gen up and then it died. I tried a few times and started to run then died every time.

OK now what had changed??? I had the outside tank open and the inside closed as usual so I never completely run out. I went outside and turned the transfer switch to the inside tank and opened it up leaving the outside tank open. Went inside and sure enough the gen fired and stayed running.

Raised the Satellite Dish and turned on the furnace and had a nice evening staying warm and watching NETFLIX. Well I fell asleep and around 12:30 am the gen stopped. I just went ahead and fell back asleep and woke at 5am thinking OH SHITE I bet both tanks are empty and my dish is sticking up. I had thoughts of having to disconnect and find propane.

Then my foggy brain kicked in and checked the tanks. Sure enough the inside tank ran out and the outside was still full even tho the transfer should have switched. So swapped the tanks and opened the inside tank and WA-LA the gen fired right up stayed running and allowed me to store the rooftop dish.

So now can someone please explain what the lack of a check valve has to do with the gen not staying running???

Opposite end of my finger has the built in check, new hose does not.

FYI the Mr Heater hoses are nice quality and US Made.

[Lantley]

Cummins12V98 wrote:

blofgren wrote:
Thanks for the follow up. I still don't understand why the automatic changeover valve would not prevent propane from flowing from one tank to the other though. :h

.

That was my point a few post ago. The check valve ensures no back pressure because gas can only flow one way. Otherwise there is back pressure which ultimately reduces flow.
The notion that the changeover valve controls the reverse flow is incorrect.

[Cummins12V98]

blofgren wrote:
Thanks for the follow up. I still don't understand why the automatic changeover valve would not prevent propane from flowing from one tank to the other though. :h

Bottom line I need a check for my gen to run.

My transfer switch works as it should.

[Bobbo]

I am not convinced the backflow preventer did anything. It still sounds to me like the high flow shutoff kicked in. Maybe the backflow preventer restricts the propane flow just enough to keep that from happening. My system works just fine with 2 pigtails without backflow preventers. I installed them early this past summer when my two pigtails started leaking propane.

blofgren wrote:
Thanks for the follow up. I still don't understand why the automatic changeover valve would not prevent propane from flowing from one tank to the other though. :h

If the auto-changeover regulator let both tanks connect to each other, it would draw down both tanks at the same time rather than let one tank run dry, then switch over to the second.

[blofgren]

Thanks for the follow up. I still don't understand why the automatic changeover valve would not prevent propane from flowing from one tank to the other though. :h

[MFL]

Thanks for letting us know that the problem has been solved. Great follow up, including pics!

I suspected that the valve was needed, even though propane guy (that should know) said not. Now we all know it is.

Jerry

[larry_barnhart]

Great story. Nice to have a quality knowledgeable owner. chevman

[Cummins12V98]

Stopped bu SunBird RV in Indio, CA. Talked to the new owner explained what was happening with the new hose without the check valve. He reached down right by the cash register and said this is what you need!

I screwed the new check onto the new hose then removed the brass fitting in the change over valve. Applied yellow teflon paste to the threads and screwed the new assembly into the change over. Hooked up the "NEW" side opened that tank and closed the old side. Fired off the gen and guess what??? The darn gen stayed running. So much for "The check valve is not needed".

[Cummins12V98]

wa8yxm wrote:
Reading this thread I nominate the "Excess flow" Feature for best answser.

Did not think of that but the new coupler may have a flow limiter.
Generators such BIG TIME.

Looking into the end of the new hose there is nothing but air. Looking into the end of the old hose there is a brass pc.

I would think the old hose has the "limiter" ???

[wa8yxm]

Reading this thread I nominate the "Excess flow" Feature for best answser.

Did not think of that but the new coupler may have a flow limiter.
Generators such BIG TIME.

[Cummins12V98]

bgum wrote:
If you had used your old line with a new crimp you wouldn't be confused as to the problem. Read this twice and possibly you will learn something.

My old line was hard and stiff and was not worth spending a nickel on it.

I totally understand the old line was doing whatever job it needed to do EXCEPT it was leaking.

So no one knows if there is a screw on device that can be added to my new line?

I understand if I had the hose fixed we would not be discussing this!!!

[bgum]

If you had used your old line with a new crimp you wouldn't be confused as to the problem. Read this twice and possibly you will learn something.

[Grit_dog]

Like the propane guy, I cannot think of a plausible reason that it wouldn’t run with a no back check hose.
Got me stumped too.
I’ve also not seen a pigtail with a check valve on it until you mentioned it and I looked it up, so my experience is 0.
Safe travels.

[Cummins12V98]

MFL wrote:
This is a dilemma which OldBiscuit could answer. He knows all things propane! I know he is N/A here any more.

I know you're not asking for WAGs, but here is mine. I'm thinking the gen is more sensitive to line pressure, than other appliances you mentioned.

Jerry

Thanks Jerry! I think you are correct. I just have no idea what that valve does.

Anyone have a part number I can add to the end of my new line to duplicate the function of the old hose?

[MFL]

This is a dilemma which OldBiscuit could answer. He knows all things propane! I know he is N/A here any more.

I know you're not asking for WAGs, but here is mine. I'm thinking the gen is more sensitive to line pressure, than other appliances you mentioned.

Jerry