Air in the water line

[Mike Groves]

We're full-timing and have found ourselves using the house water pump a lot this week as we camp in a relative's driveway on Whidbey Island, Washington State.  Our pump has been sounding a bit different (louder) and we've noticed that at times air comes out of the faucet and this takes place routinely, not just when we switched over from a water connection.

Can anyone tell me where this air in the system would come from? 

We thought perhaps our fresh water tank was getting low even though our CMP still read 30-50% (perhaps a false reading) but we filled up yesterday and still the same issues.  The pump sounds louder but somehow air is mixing in.  When the pump is off it stays off - no problem there - so there's not a leak in the system.  It is colder here but the enclosed tank area is kept between 50-65 depending on how we're heating.

Mike

[David T. Richelderfer]

I assume your coach is hooked up to the shore water supply.  If so, then the air could be coming through the shore water supply.  A few weeks ago here a couple fellows had the street water shut off to dig up and repair the main water line.  After repairs were made we had air in the shore water supply for a day or two.  But the house where you are parked would also have air in its lines if this were the culprit.

Outside of that prospect it's likely your coach's water pump going out.  We replaced our coach's water pump a year ago.  I do not remember any strange noises, but I do remember the few weeks leading up to its complete failure was evidenced by cycling of the pump when it should not have been pumping.  I suspect the interior of the pump had developed a gasket leak and water got into the electrical components.

Another thought is a cracked pipe or bad connection in the piping between the water pump and the fresh water tank.  When the pump engages some air may be getting sucked into the water line.

[Mike Groves]

We are not connected to a water supply we are self contained.

Mike

[Fred Brooks]

   Greetings Mike,
   Merry Christmas and Blessings, If you are on the pump only and there are no obvious leaks, the air leaking into the system is on the supply side of the pump. I have seen over the years you can have air getting into the supply side at the strainer/filter or a crimp clamp some where between the tank and the pump. The compromise can be small enough not to drip with no demand but allow air in under suction. If you have the resources to fabricate an alternative supply line from a bucket to the pump this will prove the issue.
    Regards, Fred

[Mike Groves]

Thanks Fred, I'll look into it. 

Mike

[Keith Moffett]

Here's a thought.  If the residual valve in the pump is failing, it wont maintain the prime from the tank.  If this happens the air in the tank takes the place of the water in the line up to the pump.  I have made this supposition before and replacing the pump seemed to resolve the problem.

Good luck and I hope you had a merry Christmas.  We are in Port Angeles, Wa

[Mike Groves]

Keith,

Thanks.  I'll research it.  Not as much air in the past day and Margaret thinks it is working "like it always has".  All we did was fill the tank.  I wonder, if the tank is higher than the pump that might force more water pressure at the inlet to the pump.

Mike

[Joel Ashley]

Like Fred, the first place I'd look is the connection(s) where the hose from the tank enters the filter and pump, because air is entering the pump probably from the supply side, and the pump is easiest to access for inspection compared to the tank end, and has the most likely failure points. 

Ours has a white plastic, easy-grip "tabbed" nut connecting the supply line to the filter head, and I think the filter head just screws onto the pump.  The white nut is easy to get a hold of with fingers to check its snugness, as is the filter and its head/holder.  Check also that the clear filter housing itself is snug into its holder/head, as air could be sneaking in around its large, round seal.  You may just want to remove the filter screen while you're at it for any necessary cleaning;  and check the seal integrity at the same time.

I suppose air could enter via the outlet hose connection, but lack of direct suction on that side makes the intake end a more likely place to look first.  After that, you'd have to direct your attention to the supply hose connection into the tank, a little harder to find and get at.

Then as others prescribe or imply, the pump's internal seals are going and it's nearing time for a new one.  But air intake is not necessarily a symptom of internal seal failure, since unless there's some sort of vent into the pump interior, air shouldn't get in that way.  I'd think seal failure should mostly evolve just poor pumping;  been there done that on the old Pace Arrow.

-Joel