Water pump thumping noise

Submitted: Wednesday, Jun 11, 2008 at 21:05
ThreadID: 58664 Views:5169 Replies:5 FollowUps:3
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Hi. We are new to caravanning & about 4 weeks into our trip around Oz. Our water pump sometimes makes a really loud thumping noise when we turn the tap on. Most of the time we hardly notice it and then other times I think the whole caravan park can hear it!! It first started when we had some battery issues so we thought it was related to that because it got better after the battery was sorted. We are currently in Alice Springs and it has started again - but mainly in the morning and night time. Could it have something to do with the colder weather?

Hope someone can shed some light on the issue :)

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Reply By: donk - Wednesday, Jun 11, 2008 at 21:08

Wednesday, Jun 11, 2008 at 21:08
When you are in van parks & the noise happens are you connected to a mains pressure tap or are you just using water out of your onboard tanks with no connection to the mains

Regards Don
AnswerID: 309359

Reply By: Member - Royce- Wednesday, Jun 11, 2008 at 21:12

Wednesday, Jun 11, 2008 at 21:12
I'm guessing that maybe the water is not filling the pump... i.e. it's pumping air at times. Maybe between use the water drains back past the pump and it has to suck air and water for a while.

Does it get better once the water flow has started?

Can you get to the intake pipe to check out if it is full beside the pump?
AnswerID: 309361

Reply By: Member - Matt H (SA) - Wednesday, Jun 11, 2008 at 21:19

Wednesday, Jun 11, 2008 at 21:19
Sounds like good ol' cavitation to me. Usually caused by air getting into the system. Maybe there is a small leak letting in air or maybe air from inside the tank is siphoning back into the lines/pump. Assuming you are using storage tank water.
If not, maybe fitting a anti-hammer washer to the tap might solve the problem if it's mains pressure water you are using.
So many variables here..sorry!

Cheers, Matt
AnswerID: 309363

Reply By: leeb1973 - Wednesday, Jun 11, 2008 at 21:25

Wednesday, Jun 11, 2008 at 21:25
Thanks for the quick replies.

The thumping noise has happened while connected to mains pressure tap and while using tank from water (while free camping).

My husband will check to see if air is getting in somewhere as that sounds like a possible cause.

Thanks again.

AnswerID: 309366

Follow Up By: donk - Wednesday, Jun 11, 2008 at 21:28

Wednesday, Jun 11, 2008 at 21:28
On most vans when you are connected to mains the van onboard pump shoud be switched off

Is this what you are doing

As a matter of interest what brand of van do you have

Regards Don
FollowupID: 575356

Follow Up By: leeb1973 - Wednesday, Jun 11, 2008 at 22:45

Wednesday, Jun 11, 2008 at 22:45
No we have not been turning the pump off when connected to mains water. We didn't know we were supposed to!! We just tried it without the pump turned on and it works beautifully.

Do you think we might have damaged the pump in some way by having it on when we shouldn't have?

The van is a 2005 Jayco Expanda that we bought in January this year.

Thank you for your help.

FollowupID: 575386

Reply By: donk - Wednesday, Jun 11, 2008 at 23:16

Wednesday, Jun 11, 2008 at 23:16
Not sure what,if any damage it may have caused to the pump but if it is working ok i wouldn't be to worried

One thing i have noticed is on our 2004 heritage the pump actually works when turned off when you flush the toilet while connected to the mains

If yours is the same if the tanks get empty it will suck air into the toilet flush water & you will get strange noises when you flush (if your toilet is electric flush)

If this happens put some water in the tanks,turn the mains off,turn the pump on & turn on a tap inside the van until the air is purged out & then turn the pump off ,the mains back on & it should have fixed the problem when you flush the toilet

Also something to be aware of is if you have two tanks you should have taps in the supply lines before the point where the two supply hoses T into the one inlet hose to the pump & you should only have one supply tap open at a time so you don't suck air from a empty tank (if one tank is empty & the other has water in it) into the pump supply line

Godd luck

Regards Don

AnswerID: 309396

Follow Up By: Member - DAZA (QLD) - Thursday, Jun 12, 2008 at 07:35

Thursday, Jun 12, 2008 at 07:35
Hi All

When filling your tanks, always fill them slow, that way eg, air comes
out at the same rate as water going in, no airlocks in tank or lines,
also just to make sure you have purged air out, turn on tap just as
tanks are just about full , that will let air out completely, another
thing is to check to see if the outlet side of the pump has a
non-return valve to stop the water between the pump and your taps
draining back, some caravan manufacturers dont put them in to save
dollars, a little bit of advice from and old Plumber.

FollowupID: 575412

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