Air in water pump on the caravan

Submitted: Sunday, Nov 28, 2010 at 20:27
ThreadID: 82741 Views:12574 Replies:5 FollowUps:5
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Hi,
My question concerns the water pump on my 3 year old Jayco Destiny.
Regardless of water levels in the two tanks, full or low, the pump will often not stop because of air in the system.

The pump is not externally leaking water, and all water hoses show no sign of leaks, but somehow air is entering the system and causing the pump to continue pumping after the tap is turned off, and while the water is running there is a lot of air coming out of the tap. Naturally the pump cannot compress air and senses low pressure causing my dilemma.

Can anyone give me a clue what maybe causing this, IE seals in pump or something else?
Cheers OnPatrol
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Reply By: Member - Christopher P (NSW) - Sunday, Nov 28, 2010 at 20:32

Sunday, Nov 28, 2010 at 20:32
you might want to see if there is a check valve in the line. a check valve will stop the water from syphoning back into the tank.

Or if you do have a check valve, you made need to check the seals
AnswerID: 437196

Reply By: Member - Toyocrusa (NSW) - Sunday, Nov 28, 2010 at 20:34

Sunday, Nov 28, 2010 at 20:34
Hi Tony. Not sure if you have a shower. With mine I have to bleed it at the front (kitchen) and back (handbasin) some times to get the air out. If you only have a tap at the front then I am not sure. Bob

AnswerID: 437198

Reply By: On Patrol & TONI - Sunday, Nov 28, 2010 at 20:38

Sunday, Nov 28, 2010 at 20:38
Thanks Chris & Bob
I will check those things out.
Colin.
AnswerID: 437201

Reply By: Rockape - Sunday, Nov 28, 2010 at 20:39

Sunday, Nov 28, 2010 at 20:39
Mate,
if the non return valve is ok, which I doubt is your problem as when you turn the tap off that should hold the water in the pump and stop it syphoning back and letting air enter.

I would look at a leak on the suction side of the pump, it may not leak when sitting but when you turn the pump on it can suck air. It may even be a seal in the pump.

Hope you find the problem
AnswerID: 437202

Follow Up By: newbies - Monday, Nov 29, 2010 at 21:59

Monday, Nov 29, 2010 at 21:59
I had a similar experience with my new (i.e. 2nd hand) Free Spirit in late July, but it was more to do with low water level in the tanks and being parked on a side-slope (I think!). Pump ran on without stopping after water ceased to flow out of the tap - must have been sucking air. Had to turn off the power to the pump. Seems as if the original owner also installed a Davey 2 litre pressure tank between the pump and the tap - designed to allow tap to run for 2 litres without the pump being switched on (e.g. to keep the noise down at night when in a caravan park, etc).

However, I have another water issue - the drinking water tap (i.e. only draws from one tank and through a replaceable cartridge filter) only sends water 'pulses' out, but at low volume on a continuous basis while the tap is 'on'. It sounds like a machine gun being fired - very disconcerting. As I am new to the caravaning game, is this a normal circumstance for filtered potable water taps? The pump looks identical to the other one for non-potable water supply. Any advice would be appreciated.

Mike
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FollowupID: 708790

Follow Up By: Rockape - Monday, Nov 29, 2010 at 22:24

Monday, Nov 29, 2010 at 22:24
Mike, the accumulator or tank as you call it is designed to stop the pump constantly stop/starting. my bore pump has an air bladder in the accumulator so the pump builds pressure to around 70psi then doesn't cut back in till around 50 psi (adjustable). What I believe is happening is you have no reserve when the pressure drops and the pump kicks in on low pressure.

If I remember correctly a sureflow pump sounds the same as you describe. Great pump but a little noisy. Put a pressure tank on it and I think it will fix your problem.

Have a good one
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FollowupID: 708801

Follow Up By: newbies - Saturday, Dec 04, 2010 at 17:06

Saturday, Dec 04, 2010 at 17:06
Thanks Rockape. Works OK so I guess I'll get used to the 'pulsing' (or not use the potable water tap when I can get good quality water from the other 3 tanks). And there is no hand pump, by the way.
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FollowupID: 709405

Reply By: Notso - Sunday, Nov 28, 2010 at 22:19

Sunday, Nov 28, 2010 at 22:19
If it has a hand pump in the line, it may be sucking air back through the hand pump, won't show up as a leak as the pump is higher than the tank.

I ended up putting a shut off valve in the line.
AnswerID: 437209

Follow Up By: On Patrol & TONI - Monday, Nov 29, 2010 at 18:04

Monday, Nov 29, 2010 at 18:04
Hi Notso
I was also told this on a C/Van forum. I bloked the hand pump and hey presto problem solved. I liked your idea about a shut off, I will do that, so if needed the hand pump is still available.
Thanks Colin.
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FollowupID: 708725

Follow Up By: Notso - Monday, Nov 29, 2010 at 18:25

Monday, Nov 29, 2010 at 18:25
Yep, it seems to happen a lot with the hand pump, I tried a non return valve in the line first but the hand pump didn't like it, so the shut off valve ended up the only answer.

It's a cost saving thing by the builders, if they put the hand pump on a separate line directly to the tank it wouldn't happen.
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FollowupID: 708728

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