# A puzzling problem with electrics



## 100127 (Jul 20, 2006)

In the Autotrail V line there are two taps. One for the kitchen sink and one in the bathroom which when pulled out on its pipe doubles as a shower head. The problem is, that whilst not having the battery charger switched on all water pressures are fine. Switch the battery charger on and there is excessive pressure at the kitchen sink, but in the shower, when you get the desired temperature, the pump runs for a few seconds, then switches off for a few seconds and switches back on.This goes on throughout the time you are using it. The problem is, that when it switches back on the water is scalding hot and as we like the higher temperature shower it makes it impossible to use. Turn the battery charger off and all is well. Anyone else had this problem , or is it a Sargent/ sureflow problem?


----------



## Penquin (Oct 15, 2007)

It sounds like a voltage issue to me, the system works well when the battery is delivering 12v (nominal), but with the charger switched on the supply is around 14v AFAIK.

This means that the pump will run faster and therefore reach a higher pressure quicker.... at which point the pressure switch turns off the pump.....

but the pipes already have hot water in them and as the pressure falls as the tap is open the hot water is flushed out.....

That would be my thoughts, but how to sort it I do not know.......

it may be a case of simply adjusting the pressure setting if that is possible so that the pump does not cut out as quickly when the charger is switched on - this would allow the pump to continue to run and allow you to adjust the temperature to what you require. That would not effect the flow when the charger is off as it would not reach the higher pressure....

BUT I do not know if your pressure settings can be adjusted......

Not sure if that helps, but that's the way my thinking would go.....

it's a fault with the pressure setting rather than the pump or the Sargent supply.

Dave


----------



## listerdiesel (Aug 3, 2012)

If it was simply a pressure setting, the pump would still do its thing just the same?

It depends on whether the pump is controlled by a relay or something more sophisticated, which seems to be the norm these days, plus there may be other parts on the circuit which are affected by the higher voltage, such as solenoid water valves?

Peter


----------



## listerdiesel (Aug 3, 2012)

Just applying a bit of thought and logic to this.

The assumption is made that the shower has hot AND cold feeds to the shower head/mixer, and the kitchen sink has twin taps or a mixer?

So, the problem should arise with both outlets, all else being equal.

If the shower head is a mixer rather than twin taps into a common hose outlet, I'd start there first, as the shower should exhibit the same high pressure as the kitchen taps.

Peter


----------



## Pat-H (Oct 30, 2009)

I agree the pump start stop is likely due to the higher speed when the charger is on. The higher speed will deliver more water. The pressure will go higher and the pump shut off.
At this stage the extra capacity in the water heater will cause that to continue to flow while the cold feed has slowed due to the pump stopping causing the hot flush....

You could look at adding a water pressure regulator

http://www.ebay.co.uk/itm/Fiamma-A2...ervan_Caravan_Accessories&hash=item2a437807eb

That may help even out the pressure.


----------



## 100127 (Jul 20, 2006)

listerdiesel said:


> Just applying a bit of thought and logic to this.
> 
> The assumption is made that the shower has hot AND cold feeds to the shower head/mixer, and the kitchen sink has twin taps or a mixer?
> 
> ...


Both taps are mixer type Peter, and I can see that there is hot and cold feed to the shower mixer.

Bob


----------



## listerdiesel (Aug 3, 2012)

These little motors are not really voltage sensitive, they are designed for 10-14 volts or so, and they are driving small centrifugal pumps so not likely to get stressed when pumping against a tap that is closed.

If all taps are mixers, then they should all perform the same.

I think a quick check on hot / cold / both should be performed on the three sets of taps to determina exactly what the operating fault is?

Peter


----------



## Charisma (Apr 17, 2008)

Pat-H said:


> You could look at adding a water pressure regulator
> 
> http://www.ebay.co.uk/itm/Fiamma-A2...ervan_Caravan_Accessories&hash=item2a437807eb
> 
> That may help even out the pressure.


I fitted one of these in my last van for exactly the problem you describe and it fixed it - highly recommended!

Dave


----------



## Pat-H (Oct 30, 2009)

I'm sticking with there being some air at the top of the water heater that gets compressed and then that pushes the hot out as the pressure drops due to the pump stopping.
The cold has no such capacity.


----------



## Poulbot (Nov 8, 2013)

My advice is to fit an accumulator tank in the system. If you have pressure fluctuation problems caused by either restrictions in the system or changes in the voltage, the accumulator tank, fitted to the pressure side of the pump, will smooth out the flow. 
Just on another point, if the pump fitted is a Shurflo, then it is not a centrifugal pump. It is a diaphragm pump which comprises of 3 pistons set on an eccentric cam. It will always try to deliver a set amount of water per minute.


----------



## 100127 (Jul 20, 2006)

listerdiesel said:


> These little motors are not really voltage sensitive, they are designed for 10-14 volts or so, and they are driving small centrifugal pumps so not likely to get stressed when pumping against a tap that is closed.
> 
> If all taps are mixers, then they should all perform the same.
> 
> ...


Been onto the chappies that I bought it from, and the tech guy said he had a problem like mine, but in a caravan. Adjustment to the shurflo pump, allowing more to the shower than the kitchen sink, cured it. Anyway, booked it on 2nd Oct for that and other minor things. Thanks all for the help.

Bob


----------



## gorsecover (Jun 29, 2011)

Just a small point, a tap used in the sink will deliver more pressure than one with an extended hose held in a higher position for a shower.
The reason being is every extra foot water has to climb loses 0.49 1b/psi due to head pressure.
Martin


----------



## hampsterracing (Jun 2, 2011)

Also the shower head flow is restricted by the shower head so the pressure at the pump will be higher


----------



## exmusso (Jun 18, 2006)

Blobsta said:


> In the Autotrail V line there are two taps. One for the kitchen sink and one in the bathroom which when pulled out on its pipe doubles as a shower head. The problem is, that whilst not having the battery charger switched on all water pressures are fine. Switch the battery charger on and there is excessive pressure at the kitchen sink, but in the shower, when you get the desired temperature, the pump runs for a few seconds, then switches off for a few seconds and switches back on.This goes on throughout the time you are using it. The problem is, that when it switches back on the water is scalding hot and as we like the higher temperature shower it makes it impossible to use. Turn the battery charger off and all is well. Anyone else had this problem , or is it a Sargent/ sureflow problem?


Hi Blobsta,
We had exactly the same problem in my Bessacarr E480.

I investigated and found the hoses feeding the shower were running all the way along the offside, along front of garage and the eventually forward to the sink/shower mixer tap which also extends from the sink.

Pump ran for a few seconds, switched off then back on with scalding water.

I increased the pump pressure slightly - dramatic difference and no worries of scalding.

Concluded it was the length of the run and the build up in pressure (hydrostatic head) was fooling the pump into shutting down.

Hope this helps,
Alan


----------



## gorsecover (Jun 29, 2011)

Sounds interesting. How do you increase pump pressure?

Martin


----------



## 100127 (Jul 20, 2006)

exmusso said:


> Blobsta said:
> 
> 
> > In the Autotrail V line there are two taps. One for the kitchen sink and one in the bathroom which when pulled out on its pipe doubles as a shower head. The problem is, that whilst not having the battery charger switched on all water pressures are fine. Switch the battery charger on and there is excessive pressure at the kitchen sink, but in the shower, when you get the desired temperature, the pump runs for a few seconds, then switches off for a few seconds and switches back on.This goes on throughout the time you are using it. The problem is, that when it switches back on the water is scalding hot and as we like the higher temperature shower it makes it impossible to use. Turn the battery charger off and all is well. Anyone else had this problem , or is it a Sargent/ sureflow problem?
> ...


Thanks Alan, but if I shove the hose back into the sink tap and turn it on, it does just the same, on, off, on off.
No doubt the company I bought it from will fix it.

Bob


----------



## cabby (May 14, 2005)

Maybe stayed with the AT, is creeping into your mind. :lol: 

cabby


----------



## 100127 (Jul 20, 2006)

cabby said:


> Maybe stayed with the AT, is creeping into your mind. :lol:
> 
> cabby


Still an AT Cabby, we changed as I did not fancy the wife skydiving out of the hab door. Just teething problems, I hope. :lol: :lol:


----------



## exmusso (Jun 18, 2006)

*Pump Pressure Adjust*



gorsecover said:


> Sounds interesting. How do you increase pump pressure?
> 
> Martin


Hi Martin,
Removed the pump and following the instructions, turned the pressure screw half a turn - important not to turn it too much.

Re-fitted and tested OK.

Considered fitting a higher pressure/flow pump if it didn't work but no need.

Cheers,
Alan


----------



## gorsecover (Jun 29, 2011)

Thanks Alan


----------

