Poor water pump performance

[Caroline_374426230]

We have recently replaced our water pump but found the flow was very poor. When tried it on a friend's van it worked ok and so we put it down to a low battery.

Have replaced battery and although flow a bit better still not as good as should be. Any suggestions?

Also we have discovered that the caravan is fitted with a surge damper. What is this for and does it need replaced from time to time?

 

[ProfJohnL]

Hello Caroline,

I have to assume that your original pump was satisfactory, but then for some reason needed changing. Did you need to change it because the water flow was poor in the same way that your new pump is poor? If so that indicates that something has changed in your water system.

Are both Hot and Cold affected?

If only hot is affected, and you have a Carver Cascade water heater, it is almost certainly the non return valve that is fitted to the heaters cold water inlet. During the winter any water left in the pipe work to the heater may have frozen and dislodged the 'O' ring seal in the valve. Sometimes this can be just repositioned , or the valve may need to be replaced. To avoid this do ensure te water system is completely empty during winter storage.

Are both Hot and Cold are equally affected?

Then some restriction has occurred near the water inlet to the caravan. Look for a kinked pipe.

If the caravan has a water filter on the in inlet, it may need replacing.

If the pump is controlled by a pressure switch, it may need adjusting, or its non-return valve may have jammed, sometimes repairable or replacement needed.

Did you replace the pump with exactly the same model?

There are different models and makes of pumps, and they do have different performances, you may have chosen a pump with a smaller delivery than your original.

 

[Caroline_374426230]

Hi John

Thanks for the advice'

The old pump had broken.

Both hot and cold are affected.

Would the surge damper affect this?

Caroline

 

[Maginnis]

Hi Caroline

We had big problems with our water on our first outing with our new (to us) van after lots of investigations and some fabulous help from the guys on here we discovered the taps filters were full of debris.

Once I managed to get the ends off the taps and the filters apart we have perfect fast flowing water. We had spent

 

[Caroline_374426230]

Hi Tina

Thanks for this - I have had probs with debris in tap filters in the past and have checked this.

Still a good tip as first approach to any probs with water flow.

 

[xtrailman]

Caroline

The surge damper should not be the problem, a lot of vans don't even have one fitted.

I believe its just a spring in side the tube, it tends to absorb high pressure pulses from the pump, like a capacitor in an electrical circuit.

Have you checked for volt drop at the pump connections?

I assume its the in the barrel type?

If so have you checked for water/damp inside the pump plug?

 

[ProfJohnL]

Hello Caroline,

Do check Ray's point, but to answer yo question about the surge damper, I do not expect it to affect the pump delivery, but its inclusion does tell me you have a pressure switch controlled pump.

Just for your information:- Because there is a small air volume at the top of the water heater tank which is designed to be there to allow space for the water to expand as it heats up, after heating the air is compressed a little. When you open a tap, the compressed air tries to push hot water out of the tank, In a system with a mixer tap (Sink or Shower) this will prevent the cold water flowing as it back feeds into the cold pipework and keeps the pressure switch satisfied until the air pressure has dropped. At this point the pump will cut in and deliver cold water. In some systems this will repeat whilst the tap is open which alternatively delivers pulses of hot water and mixed water. Clearly this is not good for a shower with the possibility of scalding. So to help prevent this and similar sized air container surge damper)is coupled to the cold supply. This pressurises as the pump runs and as the pressure switch comes up to threshold. When the taps are opened both the pressurised air in the hot tank and surge damper expand and push water out until the pump cuts in.

 

[xtrailman]

caroline

If as JL says you have the pressure switch system, then the pressure switch could have a sticking non return valve inside, read the link below. The last post.

http://www.practicalcaravan.com/newforums/fm_messages.asp?FO=1&FM=450780