30# LP Regulator Questions and system design

[brianharrison]

I have a questions regarding the 30# (high pressure regulator) on coachs with two regulator setup - ie 30# high pressure regulator on doorside tank and low pressure regulator after switching valve (in series).

What is the reason for using a high pressure regulator? Is it for system protection? - ie hose travelling across coach is not rated for full LP tank pressure? Or is it for code reasons - cannot pass HP LP through areas with human occupancy? Why could I not simply remove this high pressure reguator and flow direct to auto switch over valve?

My recollection this high pressure let down (after regulator) on door side flows through a hose and ties into ODS auto switch over valve which has ODS tank pressure tied into it as well. It would seem the auto swithover and low pressure (final) regulator can accomodate full tank pressure (it is tied into ODS tank this way). Am I missing something?

As an aside question - I read in my search here that someone mentions an overflow protection built into the hose - true? or false? I beleive false but thought I'd ask.

Thanks in advance.
Brian

 

[danemayer]

I think metal is required to cross the RV if at high pressure. Safety issue.


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[StevenJ]

The pressure regulator maintains appliance at 9.5 inches w.c., this is approx. 1/3 of 1# psi, the standing pressure in the lp bottle can run as high as 120# psi, if you bypass the regualtor you will damage all the gas valve on your appliances and when the appliance turns on your rv will catch on fire or explode, PLEASE don't alter the lp gas system and piping unless you know 100% for sure what you want to do is ok, don't mean to be blunt, but your dealing with a dangerous gas that can cause personal harm or death.

 

[brianharrison]

The pressure regulator maintains appliance at 9.5 inches w.c., this is approx. 1/3 of 1# psi, the standing pressure in the lp bottle can run as high as 120# psi, if you bypass the regualtor you will damage all the gas valve on your appliances and when the appliance turns on your rv will catch on fire or explode, PLEASE don't alter the lp gas system and piping unless you know 100% for sure what you want to do is ok, don't mean to be blunt, but your dealing with a dangerous gas that can cause personal harm or death.

Thank you Steven for your concern however my question concerns the 30# high pressure regulator and it's design purpose in a RV installation scenario. I am aware of LP gas, and modifications to OEM sytems; that was not my question in the original post.

Thanks Dan for your succint answer - are you aware of reference to RV codes or other that specifies as such? I am still searching online.......

Brian

 

[danemayer]

It's probably addressed in UL 592, which covers LP systems and hoses in RVs, but the standards docs are available for purchase. I'm not aware of any source to download them for free.

I'm pretty sure there are different standards for high pressure hoses and low pressure hoses. The pigtail between tank and regulator is high pressure. The hose running across the RV is low pressure. If you remove the regulator, high pressure LP will be going through a hose that's designed to carry low pressure.

I'm not sure which is less expensive: hose designed for high pressure, or pipe. But you can be sure that no manufacturer would spend $40 extra meeting UL standards by using high-pressure pipe or hose when a $10 regulator does the job.

 

[brianharrison]

... But you can be sure that no manufacturer would spend $40 extra meeting UL standards by using high-pressure pipe or hose when a $10 regulator does the job.

Yup I agree.

Thanks again.

Brian

 

[iowaone]

The pigtail hose with the green fitting on it does have high flow or leak protection built into it. If there is a leak it shuts down. Therefore they put the 30 lb regulator on the system to prevent it from shutting down when you first hook up a newly filled tank. If that isn't there with the empty pipe going across the camper it would act like a leak until it is filled and shut down the pigtail saftey device. If you remove the 30lb regulator than each time you hook up a newly filled tank you will have to open the valve very, very, slowly until the pipe across is filled. There may be other reasons for the regulator too but the practical effect of removing it is what I just explained. I have a long high pressure hose for a stove attached to mine before the regulator. I had to add a regulator close to the tank or the pigtail would shut down anytime I hooked up the empty long hose. I hope this is a helpful and understandable explaination.

 

[brianharrison]

Thanks iowane for your insight on the "flow limiting device" on the pigtail - I searched some more and found the info - I posted it to another thread with a specific title - it was a learning for me so hopefully it will help others as well.

Dan - I found this cheatsheet for hoses; and this OSHA 1910.110 standard which deals with hoses (section 1910.110(b)(9)) and there is some other good info on LPG containers, pipe etc. You may already have intimate knowledge or access to this standard.

Brian

 

[danemayer]

Looks like the relevant language is:

Hose subject to container pressure shall be designed for a bursting pressure of not less than 1,250 p.s.i.g.

Hose and hose connections on the low-pressure side of the regulator or reducing valve shall be designed
for a bursting pressure of not less than 125 p.s.i.g. or five times the set pressure of the relief devices
protecting that portion of the system, whichever is higher.

 

[Rodbuster]

The information on this thread has helped me out so much.
I've been having a problem with only the doorside propane tank. Please understand that I have never fiddled with anything to do with LP except to get my bbq tank filled when needed.
Anyways, I tried different things to make it work, I even took the advice that somebody posted to open the valve real slooow. Nothing worked. I went out and purchased a new 30# regulator (the red one) and that didn't work either.
Then I remembered something that Dan (Danemayer) posted. He was having a LP issue also. He said that when he purchased his regulator, the service tech suggested that he change his "pigtail" also. I didn't understand that because in my mind the pigtail was simply a hose used to transport the fuel from one place to another. I didn't see it as having a mechanical use like a regulator has.

After reading this post I went out and purchased a new pigtail and installed it. "EVERYTHING" is working fine.
Is this a great forum or what. It has helped me out many times.

Thank you Brian, Dan (again) and Steven.
Dick

 

[brianharrison]

Happy to hear the info helped another Heartlander resolve their issue.

Brian

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