Air in water lines

mgdots · 10-27-2015, 08:18 AM

I am getting air into my water lines and I can't seem to figure out where it's coming from. I am connected to city water and the pressure is about 45-50 psi. I have checked all the connections and they are tight. I have also removed the inline filter in case the housing was leaking and water was not dripping. The only thing I have changed inside is the kitchen sink faucet to a household type. All of those connections are tight as well. I see air in all the faucets and shower.
If anyone has any suggestions on things to check I would appreciate the help.

Regards,
Mike

**hankpage** · 10-27-2015, 08:54 AM

Are you getting it from the source??? Check with neighbors or use a hose nozzle on fine mist to see if the air is coming from the CG source. JM2¢, Hank

Javi · 10-27-2015, 09:16 AM

Could be a leak or it could be that you aren't getting ALL the air out of the system when you connect to the city water line.. We always open the faucets one at a time starting with the closest to the city connection and working our way downstream bleeding the air.

Or like Hank suggested it could be coming from upstream..

Try putting a gauge in line a cutting the water off at the faucet... and watch to see if the pressure bleeds of quickly.. to check for a leak..

Steve S · 10-27-2015, 09:27 AM

Does this do this in all faucets and in the shower? My first thoughts are there's a leak somewhere. The other thing to you can do is unscrew the end of the faucets and see if there's any junk in there because if there is it'll seem like you have air in the lines. Good luck and let us know how you fixed it

GaryWT · 10-27-2015, 10:20 AM

how is the water heater, is it full of water or is there some air in there. Pull the relief valve to be sure it is free from air.

**chuckster57** · 10-27-2015, 11:10 AM

Quote:

Originally Posted by GaryWT

how is the water heater, is it full of water or is there some air in there. Pull the relief valve to be sure it is free from air.

You actually want an "air gap" in the water heater tank. This allows for expansion of the water when you heat it.

notanlines · 10-27-2015, 11:19 AM

As an add to Chuckster's response (I better add that this was "borrowed" from Motleyrvrepair.com):

The T&P valve is a temperature and pressure valve. It is a safety device designed to release when the water temperature reaches 210 degrees or the pressure within the tank reaches 124 to 150 PSI. weeping or dripping of this valve while the water heater is heating does to mean it is defective. This is the normal expansion as the water is heated in the small closed water system of a RV. Your water heater tank is designed with an internal air gap at the top of the tank to reduce the possibility of weeping and dropping. Over time the heating water will absorbed this air. To replace this air which will correct a weeping T&P valve the steps are:

Step 1 : Turn off the water heater and let water cool.

Step 2 : Turn off the incoming water supply or water pump (first make certain the system is full, up to pressure and the water heater is full).

Step 3 : Open a faucet in the coach to release the pressure.

Step 4 : Pull the handle of the T&P valve and allow water to flow until is stops.

Step 5 : Snap the t&P valve shut, close the faucet and turn the water back on.

I might add it is not a bad idea to open the t&P valve occasionally just to make certain it has not become seized up with lime deposits. The T&P valve is a safety device but will not work correctly if seized up.

He runs a very interesting site, well worth looking into.

Steve S · 10-27-2015, 12:44 PM

Quote:

Originally Posted by chuckster57

You actually want an "air gap" in the water heater tank. This allows for expansion of the water when you heat it.

X2, you need that air in your tank and pulling the handle on the relief valve isn't a smart thing to do

Pull Toy · 10-27-2015, 01:38 PM

Just my 2cents...

Air in the lines probably isn't a traditional leak, as a leak moves H2O into spaces, not air into piping. If you are getting air in lines it must be on the low pressure side of things, as the high pressure side would spew water out to the world, not air in. I'm thinking bad check valve at the 12v pump pulling air out of the empty fresh water tank into the system? The Vortex / Venturi Effect would be my guess!

Easiest way I can think of to prove it is to fill your water tank all the way and prime the pump. Then stay on city water and see if you suck air. If you still do. I'm at a loss. If not, repair or replace the check valve. The cheaper check valves are just a spring loaaded type floating ball and socket. You may be able to remove it and clean it with a "Lyme Away" type product.

Let us know what you find, and GOOD LUCK!

mgdots · 11-19-2015, 06:32 AM

I finally made it home from overseas and I'm messing around with the system. I am looking at the check valve suggestion because that makes the most sense. There is no external check valve at the pump. I assume it's either internal or located somewhere else. Any suggestions?

**JRTJH** · 11-19-2015, 07:35 AM

While there are a number of different design pumps and yours may not be "exactly the same," here is a diagram of the most common type. As you can see, there isn't a "backflow valve" separate from the pump. Essentially, the valve is a an integral part of the pump head.

Also, here is a simplified diagram of your water system. As you can see, when you're on "city water" the pump is completely "out of the system as the water enters from the campsite supply and makes a turn to the trailer system, essentially bypassing the pump.

When connected to city water, there is no "negative pressure" (vacuum) on the system that would allow air to be "drawn into" the pressurized plumbing. As Hankpage asked, "Are you getting it from the source?".

Air just won't flow into a pressurized system, so the "source" is most likely the reason for your air.

If you were getting air into your pressurized system "ONLY WHEN USING THE PUMP" I'd think you may have a defective pump head, but the pump head won't induce air into the system when you're on city water.

hankaye · 11-19-2015, 05:30 PM

mgdots, Howdy;

The tip about checking all the spigots for crud in the aerators is a good one.
Had "Air" in my vanity just last week, removed and cleaned the screens ...
problem solved.
Another good tip IMO is checking the check valves, especially the one where
the water enters the RV.
Oh, you didn't mention what year and model you have, sometimes these
are related to others from the same assembly line and someone may already
have found the solution you are looking for... just a suggestion.

hankaye

dave-g · 11-30-2015, 02:49 AM

1. hot water heater tanks are to be 100% full of water- They are not to have air in them.
2. The relief valve sits at the top of the tank- opening it to get the air out is a good thing.
3. The relief valve opens, as a safety, on high pressure ( air or water it dose not matter) but also temperature 210F. If the top of the tanks has air and no water the temperature probe will not be in the water- and it will not work.
4. If you open your relief valve and it will not re- seat it needs to be replaced. You should cycle it 1-2 times per year.
5. Yes water expands when hot- so put in an expansion tank like most homes have but rv builders are too cheap to put in.

**chuckster57** · 11-30-2015, 04:59 AM

1) RV water heaters are designed to have an air gap at the top.

2) opening it to remove the air is not a good thing

3) it does operate as a safety.

4) correct. If it doesn't seat then it should be replaced.

5) putting in an expansion tank will do nothing for the water heater.

**JRTJH** · 11-30-2015, 05:13 AM

Quote:

Originally Posted by dave-g

1. hot water heater tanks are to be 100% full of water- They are not to have air in them.
2. The relief valve sits at the top of the tank- opening it to get the air out is a good thing.
3. The relief valve opens, as a safety, on high pressure ( air or water it dose not matter) but also temperature 210F. If the top of the tanks has air and no water the temperature probe will not be in the water- and it will not work.
4. If you open your relief valve and it will not re- seat it needs to be replaced. You should cycle it 1-2 times per year.
5. Yes water expands when hot- so put in an expansion tank like most homes have but rv builders are too cheap to put in.

The first sentence in your post is not correct (for water heaters that do not have an added expansion tank in the water system. The majority of manufacturers do not add the expansion tank as you indicate, probably because it costs extra. If there is not an expansion tank, both the Atwood and Suburban water heater owner's manuals give instructions on how to "maintain" and "replenish" the air gap in the water heater tank. Both indicate that the air gap in the tank is necessary and Suburban indicates that it will, in most situations, "naturally form" as the tank is used"

The air forms a "in tank expansion valve" and prevents the pressure relief valve from weeping. One way to help eliminate a "weeping valve" is to install an additional expansion tank in the HOT water line (adding one to the cold water line will not stop the weeping valve), but that is not a design feature included in most travel trailers and, unless the owner adds it, the air gap in the water heater is necessary for "normal operation" to prevent hot water from leaking out of the pressure relief valve.

Here are the comments in the Suburban manual and the Atwood manual:

SUBURBAN: One way to reduce the frequency of this occurrence is to maintain an air pocket
at the top of the water heater tank. This air pocket will form in the tank by design.
However, it will be reduced over time by the everyday use of your water heater.
To replenish this air pocket:
1. Turn off water heater.
2. Turn off cold water supply line.
3. Open a faucet in the RV.
4. Pull out on the handle of the Pressure Relief (P & T) Valve and allow water
to flow from the valve until it stops.
5. Release handle on P & T Valve - it should snap closed.
6. Close faucet and turn on cold water supply; as the tank fills, the air pocket
will develop.
Repeat this procedure as often as needed to reduce the frequency of the weeping
of the P & T Valve. If the weeping persists after following this procedure, you may
elect to install an expansion or accumulator tank in the cold water line between the
tank and check valve to relieve the pressure caused by thermal expansion.
Contact your local dealer for assistance.

ATWOOD: TO REPLACE THE AIR GAP FOLLOW THESE STEPS:
1. Turn off main water supply (the pump or water hook up source).
2. Let water cool or let run until cool.
3. Open the hot water faucet closest to the water heater.
4. Pull handle of pressure temperature relief valve straight out and
allow water to flow until it stops.
5. Allow pressure temperature relief valve to snap shut; close faucet;
turn on water supply.
6. Turn on water heater and test.

dave-g · 12-01-2015, 02:50 AM

SUBURBAN: One way to reduce the frequency of this occurrence is to maintain an air pocket
at the top of the water heater tank. This air pocket will form in the tank by design.
However, it will be reduced over time by the everyday use of your water heater.
To replenish this air pocket:
1. Turn off water heater.
2. Turn off cold water supply line.
3. Open a faucet in the RV.
4. Pull out on the handle of the Pressure Relief (P & T) Valve and allow water
to flow from the valve until it stops.
5. Release handle on P & T Valve - it should snap closed.
6. Close faucet and turn on cold water supply; as the tank fills, the air pocket
will develop.
Repeat this procedure as often as needed to reduce the frequency of the weeping
of the P & T Valve. If the weeping persists after following this procedure, you may
elect to install an expansion or accumulator tank in the cold water line between the
tank and check valve to relieve the pressure caused by thermal expansion.
Contact your local dealer for assistance.

You are correct- That is in the manual- And its the dumbest think I have ever heard of. The rv world is strange.

At least they say "you may elect to install an thermal expansion tank"

**JRTJH** · 12-01-2015, 06:51 AM

Quote:

Originally Posted by dave-g

SUBURBAN: One way to reduce the frequency of this occurrence is to maintain an air pocket
at the top of the water heater tank. This air pocket will form in the tank by design.
However, it will be reduced over time by the everyday use of your water heater.
To replenish this air pocket:
1. Turn off water heater.
2. Turn off cold water supply line.
3. Open a faucet in the RV.
4. Pull out on the handle of the Pressure Relief (P & T) Valve and allow water
to flow from the valve until it stops.
5. Release handle on P & T Valve - it should snap closed.
6. Close faucet and turn on cold water supply; as the tank fills, the air pocket
will develop.
Repeat this procedure as often as needed to reduce the frequency of the weeping
of the P & T Valve. If the weeping persists after following this procedure, you may
elect to install an expansion or accumulator tank in the cold water line between the
tank and check valve to relieve the pressure caused by thermal expansion.
Contact your local dealer for assistance.

You are correct- That is in the manual- And its the dumbest think I have ever heard of. The rv world is strange.

At least they say "you may elect to install an thermal expansion tank"

Yup, who are we (mere mortals) to argue with the engineers who built the equipment and their "design criteria" on how to best operate/maintain the water heater. I suppose they write those owner's manuals just so we have something to read (or not) while in the bathroom and to throw away when we're done. (Can't even "use" it because the paper won't soften enough to "add to the black tank" even when crumpled like an old Sears catalog <think outhouse>) LOL Hmmmmm

Pull Toy · 12-01-2015, 03:53 PM

"<think outhouse>) LOL Hmmmmm "

When you really think about it............ in the Camper.... we kind of Doo have our Outhouse "In House"! LOL

Sorry, couldn't resist!

carwheel_09 · 04-12-2016, 09:47 AM

Wonder if a Shurflo water pump accumulator tank would work. I have the weeping and it's got old always having to go through the process to get a air pocket in the water heater.

**JRTJH** · 04-12-2016, 12:11 PM

Quote:

Originally Posted by carwheel_09

Wonder if a Shurflo water pump accumulator tank would work. I have the weeping and it's got old always having to go through the process to get a air pocket in the water heater.

If your relief valve is weeping "all the time" it probably is bad and needs to be replaced. They are available at almost any "big box store" as well as any RV parts store. If you go to Lowe's or HD, take the relief valve with you so you can get the correct length temp probe.

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