Two Regulators

[masterdrago]

I've wondered every since our PDI on Oct.31 why there are two regulator on our 3791RD.
A red on on the starboard side connected directly to the bottle, then iron pipe running across to the port side connected to another grey one with a regulator and auto switching valve connected to the other bottle. Why two?

[BB_TX]

The grey one is a regulator as well as an auto change over valve. The red one is a high pressure regulator valve to drop the line pressure going to the grey one. It is not a change over valve.

Here is one of several discussions about the red one.

That red regulator valve

[DQDick]

The short answer is as I understand it is that, because of the distance between tanks the law requires Keystone to put the red one on.

[masterdrago]

So what I'm seeing is a red single stage regulator (GR 630) that drops bottle pressure to 30psi. Feeds it across the RV in 1/2" iron pipe to one inlet of the two stage automatic changeover LP regulator. The other bottle is feeding directly (~200psi) to the other inlet of that same auto changeover vlv. So 30psi on the left (in my pix) and up to 200psi on the right. Then the auto vlv feeds to the 2 stage valve below where it drops the 30psi or 200psi down to 10" of w.c.
The valves I've been exposed to over the last 40+ years in my service work are either one at the tank (drops from tank psi to 10psi), then to the appliance where it is regulated from 10psi to 10-12" w.c. The other regulators we see are the grill and outdoor fireplace that go directly from bottle (200psi) to burner psi (~10" w.c.).
Am I seeing this picture right?

[coachgrowl]

When you say auto changeover valve does this mean that if one tank goes empty this valve will automatically switch to the other tank without me moving the lever?

[masterdrago]

Originally Posted by coachgrowl

When you say auto changeover valve does this mean that if one tank goes empty this valve will automatically switch to the other tank without me moving the lever?

That is correct. It does a change internally from all I've read.

[coachgrowl]

I have the LPG tank sensors on my tanks seem to work very well. I always wondered why both tanks went down together. You must be right about the auto changeover valve.

[DarMar]

Originally Posted by DQDick

The short answer is as I understand it is that, because of the distance between tanks the law requires Keystone to put the red one on.

Agreed and some people may have eliminated it completely!!!

[BB_TX]

It has often been said that the reason for the red regulator is that without it the line pressure in the cross over pipe would be the same as the tank pressure. And since under tank pressure the propane in the tank is in a liquid state, it would theoretically be possible that the propane in the cross over pipe could condense back into a liquid state when flow stopped. And I suppose it could then possibly go into the two stage auto change over regulator as a liquid the next time flow started. An assumption only a real propane guru could verify.

People have eliminated them thinking they serve no real purpose. And apparently with no problem. I am not ready to go that far.

[shovelhead86]

When the automatic changeover takes place does the handle move to indicate what tank is feeding?

[coachgrowl]

my handle does not move but both tanks are feeding.

[rohrmann]

Originally Posted by shovelhead86

When the automatic changeover takes place does the handle move to indicate what tank is feeding?

The handle does not move, but when the indicator turns red, it is still pointing to the empty tank. Prior to removing the tank to get it filled, manually move the handle to the other tank and the indicator will change to green, indicating that the tank has gas in it. We have been full time for over five years and the auto change valve has never failed to switch over. Depending on how cold it is, I will check the indicator every so often, and will get the empty tank filled when I see the red indicator.

[coachgrowl]

thank you for being here

[masterdrago]

Thanks from me for folks like Bob & Becky for all the assistance and great advise and feedback for all of us noobs.

[Mike117]

I am still trying to understand this auto change over. If I turn the propane on the tank with the red regulator it smells like gas and you can hear it. Don’t you have to turn the tanks on to get propane? I can turn the tank on with the switch over switch and it appears to work. I guess I am not very smart and can’t understand how propane from the other side would come on without turning the valve? My old trailer you had to turn both tanks on. Any help would be great.

[Carl n Susan]

The auto change over valve function requires both tanks to be on for it to work.

[Mike117]

Originally Posted by carl n susan

The auto change over valve function requires both tanks to be on for it to work.

Ok thanks. When I turn on the side with the red regulator I get a propane leak out of a small hole on the regulator? Bad regulator or what?

[Carl n Susan]

If it leaks I would replace it. Those red ones are cheaply made.

[BB_TX]

Originally Posted by Mike117

Ok thanks. When I turn on the side with the red regulator I get a propane leak out of a small hole on the regulator? Bad regulator or what?

That small hole is where they start leaking when they go bad. Easy to replace.

[twindman]

If you change the regulator, remember to use the 'special' gas tape on the threads, not standard water usage tape.