Water pump problem

[Steveforrest78]

Hi all... news to caravaning so please feel free to talk to me like im a 4 year old.

I have a coachman pastiche 530/4... and my aquarol truma water pump has stopped working.... im hooked up, green light next to pump switch comes on, but pump is not activating (no noise from pump, checked pump with 12v supply and it works fine... also cleaned the terminals on pump and also checked battery in caravan... holding charge just fine.... fuse for pump next to battery also good.... considered it could be the pressure switch but i wouldnt have thought the green light would come on if that were the case.... any bright ideas? Steve

 

[Damian]

Adjust the pressure switch.

 

[Steveforrest78]

Adjust the pressure switch.

Thanks damian... ive just tried that... no joy... had pump switch on and tap open... turned pressure switch all the way up and down and no reponse at all... im wondering if theres likely to be a loose connection somewhere

 

[Damian]

Your next check is what voltage is available at the pump to van connection.
How did you check the van battery for charge?

 

[Steveforrest78]

I disconnected it and ran a multimeter across it... cant out at 12.7 to 13v

 

[Damian]

Sorry I do not understand what you posted.
There is only one measurement that is relevant and that is directly between Pos and Neg.

What I dont understand is the 12.7 to 13v??????

 

[Mel]

I am not as technical as Damien, so forgive the simplistic advice, but have you tried dunking the pump end in the aquaroll up and down to clear any air in the pump. Has orked or us before.
mel

 

[Steveforrest78]

Sorry if i wasnt clear damian... the check youre referring to was the leisure battery charge that i tested.... i havent measured the voltage at the pump end yet as i dont have a multimeter to hand... getting hold of one tomorrow, at which point ill start at the terminals and work my way back

Mel... i havent tried that as of yet but surely if there were air in the pipe the motor would still try to pump... its completely silent

 

[ProfJohnL]

Based on whats been posted so far. The pump assembly will run when supplied with 12V directly to its terminals. Therefore if its not running when connected to the water inlet socket, it means the pump is not getting 12V.

The obvious check is to measure to voltage at the pump socket on the caravan. but without a meter that is difficult.

However there is one thing you might check. Depending on the make of the pump connection housing, some models use brass connection pins that are split when you look at them end on.
Over time the brass quarters or halves can bend inwards a little, and that can mean they don't make a good connection. You can try prising them apart just a little using a small screwdriver, and that might improve the connection when the pump is plugged in.

 

[Damian]

the check youre referring to was the leisure battery charge that i tested.... i havent measured the voltage at the pump end yet as i dont have a multimeter to hand

So, given what you say about not having a multimeter at hand, what did you use to check the battery?

 

[Steveforrest78]

Thanks prof... i read that somewhere else and indeed mine are chaped like that... they dont look squeezed but i will try what you suggest just in case..... the pump has been increasingly temepramental for about a year and i really had to ram it home to get it working.... im wondering if the terminals in the caravan have actually been pushed in a little and they arent connecting.... does this sound feasible to anyone?

 

[Steveforrest78]

Damian... i used a friends multimeter to check battery, but the meter is at his home and im now at the caravan.... i travel between the two quite a lot.... ill have one tomorrow

 

[Steveforrest78]

Oh... sorry, something i really should have mentioned from the start as it may be relevent... ever since ive had the van (3 years give or take) the pump has never has a watertight seal.... water leaks out from the socket like crazy when its pumping.... is this normal, could it be related, and what could cause it?

 

[Hutch]

Steve, yes the terminals on the caravan corrode and need cleaning off,, and there should be two O rings on the connector, I change mine every year, there should be no water leakage there.

 

[Steveforrest78]

Hutch.... cheers, youve just answered one problem i suspect.... theres only one o-ring on the connector and its pretty loose.... so i can get that sorted tomorrow

 

[Damian]

OK, thanks for the info about the multimeter.
Now that a fuller picture is emerging I think you have almost answered you original question.

As Hutch has said there should not be any water leaking when in use, so, that kind of points to corroded pump connections on the van.
They may be salvageable with cleaning or they maybe past saving and a new inlet may be needed.

 

[ProfJohnL]

I do recall seeing a connector with the caravan terminals pushed in, but misaligned, because the housing had started to melt, due to a poor electrical contact that started to over heat, but that also caused the plug to distort and it wasn't water tight either by then, and the damage was fairly obvious.

There are simalarities to your symptoms, but without seeing the affected parts I couldn't be certain.

If that is the problem, the only solution is to change both the plug on the pump and the housing in the caravan.

 

[Robert_374373903]

Adjust the pressure switch.

My year 2000 Topaz has no pressure adjusting screw, just a empty hole with a blue cap on it. Does that mean there is not adjusting on this model?.

 

[Damian]

It is most probable that your system is a microswitched system where opening a tap completes the circuit to the pump.

 

[Robert_374373903]

Hi and thank you for reply. You are correct in that the taps have microswitch but how does that effect the pressure?.

 

[Damian]

Hi and thank you for reply. You are correct in that the taps have microswitch but how does that effect the pressure?.

It does not.
The pressure will be that which the pump supplies.
The microswitches only turn on and off the power to the pump.

Whilst a pump may show a good flow rate when tested in something like a bucket of water, when connected to the van it has to overcome the restriction of the pipe, length of pipe, number of bends etc.

 

[Robert_374373903]

It does not.
The pressure will be that which the pump supplies.
The microswitches only turn on and off the power to the pump.

Whilst a pump may show a good flow rate when tested in something like a bucket of water, when connected to the van it has to overcome the restriction of the pipe, length of pipe, number of bends etc.

Thank you again.