Water pump intermittently running.

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May 2, 2021
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Hi all - I had a chat with Truma technical department today. In their opinion, the fault is likely to be a non-return valve inside the ultraflow filter housing fitted to the side of the van where the pump plugs in. It appears the NRV is integral to the filter housing and cannot be adjusted or replaced. Has anybody got any experience of this type of fault?
 
Nov 11, 2009
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Hi all - I had a chat with Truma technical department today. In their opinion, the fault is likely to be a non-return valve inside the ultraflow filter housing fitted to the side of the van where the pump plugs in. It appears the NRV is integral to the filter housing and cannot be adjusted or replaced. Has anybody got any experience of this type of fault?
Didn’t the OP deal with a similar problem and purchased a new housing unit. It’s in the photo.
 
Jun 23, 2019
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Yes changed the inlet housing (where you plug your external pump into side of your van) . It has a rubber washer and spring inside it which only needs a slight leek. This can be caused by a small piece of dirt or grit or lime scale. I was unable to dismantle it and clean and therefore changed the whole thing. This was only 4 screws, 2 wires and 1 water pipe about 10 mins work and £40. However very pleased it worked. See photo earlier in this thread.
 
Apr 11, 2021
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I have a similar problem to the OP but in my case the Truma pump doesn't switch off when the tap is turned off. So it's on all the time the main pump switch is on (by the door, in our Adria).

So we have to turn this main pump switch on every time we want to use a tap, or the shower, which is a real pain.

It's not due to air in the system because the taps and shower all work well with no air in the flow.

I've replaced the water pipe clamp (in the pump head) with an adjustable jubilee clip, because the clamp wasn't tight enough and often came off, causing water to be pumped everywhere outside the van. So it can't be a loose pipe.

Is the pump constantly running because the pressure switch inside the van is incorrectly adjusted? I've tried turning the white knurled knob on top both ways but I don't know what I'm doing so I might have left it in the wrong position.

Or is the problem due to the NRV inside the main housing where the pump plugs into, like the OP found out?

The Truma water pump is new from the dealer we bought the van from, and apart from me replacing the poorly fitted OE tube clamp with a jubilee clip, should be ok.
 
Mar 14, 2005
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I have a similar problem to the OP but in my case the Truma pump doesn't switch off when the tap is turned off. So it's on all the time the main pump switch is on (by the door, in our Adria).

So we have to turn this main pump switch on every time we want to use a tap, or the shower, which is a real pain.

It's not due to air in the system because the taps and shower all work well with no air in the flow.

I've replaced the water pipe clamp (in the pump head) with an adjustable jubilee clip, because the clamp wasn't tight enough and often came off, causing water to be pumped everywhere outside the van. So it can't be a loose pipe.

Is the pump constantly running because the pressure switch inside the van is incorrectly adjusted? I've tried turning the white knurled knob on top both ways but I don't know what I'm doing so I might have left it in the wrong position.

Or is the problem due to the NRV inside the main housing where the pump plugs into, like the OP found out?

The Truma water pump is new from the dealer we bought the van from, and apart from me replacing the poorly fitted OE tube clamp with a jubilee clip, should be ok.
You tell us the pump doesn't turn off automatically - that suggest the pump is not pressurising the system enough to trip the switch.
There are five typical reasons why that may be the case.
1. The supply voltage to the pump may not be correct. Is you battery fully charged?
2. The pump might be faulty and not running fast enough - have you tried a spare pump?
3. The Whale pressure switch is not correctly adjusted - check you owners manual on how to set the switch.
4 The water system drain valves have not been closed after the winter drain down - usually dumps water under the caravan.
 
Apr 11, 2021
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You tell us the pump doesn't turn off automatically - that suggest the pump is not pressurising the system enough to trip the switch.
There are five typical reasons why that may be the case.
1. The supply voltage to the pump may not be correct. Is you battery fully charged?
2. The pump might be faulty and not running fast enough - have you tried a spare pump?
3. The Whale pressure switch is not correctly adjusted - check you owners manual on how to set the switch.
4 The water system drain valves have not been closed after the winter drain down - usually dumps water under the caravan.
Thanks ProfJohnL. In answer to your points:
1. This could be the reason because although the battery is relatively new, it lost a lot of amps in the four weeks between Easter and May Day B/H - from 14.4 down to single digits. But doesn't being on EHU negate the battery issue? I've no idea.
2. I have thought about trying another pump and will be doing this soon.
3. I haven't checked the owner's manual, stupidly, but have nevertheless followed verbal instructions from a caravan dealer as to how to set it. I'll have to turn the knob both ways again but - when the water flows through the taps ok - I'm never sure where to leave it!
4. Yes, I've ensured the yellow drain valve by the boiler is in the up position.

Many thanks for these points, I will go through them next time! (y)
 
Apr 11, 2021
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Thanks ProfJohnL. In answer to your points:
1. This could be the reason because although the battery is relatively new, it lost a lot of amps in the four weeks between Easter and May Day B/H - from 14.4 down to single digits. But doesn't being on EHU negate the battery issue? I've no idea.
2. I have thought about trying another pump and will be doing this soon.
3. I haven't checked the owner's manual, stupidly, but have nevertheless followed verbal instructions from a caravan dealer as to how to set it. I'll have to turn the knob both ways again but - when the water flows through the taps ok - I'm never sure where to leave it!
4. Yes, I've ensured the yellow drain valve by the boiler is in the up position.

Many thanks for these points, I will go through them next time! (y)
I mean the drain valve is down/off!
 
Mar 14, 2005
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Thanks ProfJohnL. In answer to your points:
1. This could be the reason because although the battery is relatively new, it lost a lot of amps in the four weeks between Easter and May Day B/H - from 14.4 down to single digits. But doesn't being on EHU negate the battery issue? I've no idea.
2. I have thought about trying another pump and will be doing this soon.
3. I haven't checked the owner's manual, stupidly, but have nevertheless followed verbal instructions from a caravan dealer as to how to set it. I'll have to turn the knob both ways again but - when the water flows through the taps ok - I'm never sure where to leave it!
4. Yes, I've ensured the yellow drain valve by the boiler is in the up position.

Many thanks for these points, I will go through them next time! (y)
Normally the EHU when connected and the caravans controls set correctly the caravans internal 12v power supply should recharge the battery - but you do need to check the position of the switches to make sure its turned on.

If you supply was down to sing digits then you have a severely discharged battery, and the pump would produce less pressure. That certainly could affect the operation of the pressure switch.

Many caravanners as a matter of course carry a spare pump.

Also some stand alone battery chargers (e.g.CteK and other multistage units) will not even start to charge a battery if its terminal voltage is too low. I don't know if or how sensitive to battery voltage some caravan systems might be.

The instructions on how to set the pressure switch tell you how to judge the correct position for the switch.
 
Apr 11, 2021
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Normally the EHU when connected and the caravans controls set correctly the caravans internal 12v power supply should recharge the battery - but you do need to check the position of the switches to make sure its turned on.

If you supply was down to sing digits then you have a severely discharged battery, and the pump would produce less pressure. That certainly could affect the operation of the pressure switch.

Many caravanners as a matter of course carry a spare pump.

Also some stand alone battery chargers (e.g.CteK and other multistage units) will not even start to charge a battery if its terminal voltage is too low. I don't know if or how sensitive to battery voltage some caravan systems might be.

The instructions on how to set the pressure switch tell you how to judge the correct position for the switch.
Thanks ProfJohnL, I was thinking about buying a spare pump so I'll definitely do that and see if it's a pump issue.

If it isn't, I'll try adjusting the pressure switch again. Although that seems to be a bit hit and miss when I ask my wife - who's operating the taps - what the flow is like and I'm busy listening to what noise is coming from the pump!

I'm a bit confused about battery voltages, if I'm honest. Some people say that a battery will discharge significantly - even if it's relatively new and reasonably "healthy - so it should always be removed from the van if your're not using it for a couple of months and bench charge it at home so that it's fully charged for the next holiday.

And others, like you, suggest that the battery should retain a decent voltage - say > 12A+ - even when left for several weeks, and you don't need to keep removing it from the van and charging it. So I'm undecided what to do. The battery is a high spec one - 120Ah - and we've only had it 3 years so it should be ok. (and the light on it is still green!) But it may have been run down too much in our previous van, maybe?

Of course, a solar panel will sort this issue and I'm looking into that.

Thanks for your thoughts.
 

Damian

Moderator
Mar 14, 2005
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- and we've only had it 3 years so it should be ok. (and the light on it is still green!) But it may have been run down too much in our previous van, maybe?
A 3 year old caravan battery has been subjected to various stages of charge and discharge over that time, and not always in ideal conditions. The only way to determine its condition is to have it tested.

As for the "green light" they are a gimmick as they tell you nothing at all, apart from the one cell they look at "may" seem to be OK, it has no idea what the other cells are doing !
 
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Mar 14, 2005
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...I'm a bit confused about battery voltages, if I'm honest. Some people say that a battery will discharge significantly - even if it's relatively new and reasonably "healthy - so it should always be removed from the van if your're not using it for a couple of months and bench charge it at home so that it's fully charged for the next holiday.

And others, like you, suggest that the battery should retain a decent voltage - say > 12A+ - even when left for several weeks, and you don't need to keep removing it from the van and charging it. So I'm undecided what to do. The battery is a high spec one - 120Ah - and we've only had it 3 years so it should be ok. (and the light on it is still green!) But it may have been run down too much in our previous van, maybe?

Of course, a solar panel will sort this issue and I'm looking into that.

Thanks for your thoughts.
Lead Acid batteries which are completely disconnected will still slowly discharge over time. How long is very variable, and depends on the condition of the battery and different makes may also affect it, but for 120Ah battery it should hold a decent charge for a couple of months without a problem. If it doesn't then the battery has to be suspect.

If the battery is left connected in a caravan then there are often some appliances which might put a drain on the battery. Things like aerial amplifiers, some car type radios need a continual 12V supply to maintain the settings. Some alarm systems might be wired to the battery.

The only sure way is to remove the cables from the battery.

Its certainly a sensible precaution to make sure the battery is fully charged before you need to use it. A solar panel may be just the ticket, or bench charging it, but I do recommend using a smart charger which should prevent you accidentally overcharging the battery.
 
Apr 11, 2021
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Lead Acid batteries which are completely disconnected will still slowly discharge over time. How long is very variable, and depends on the condition of the battery and different makes may also affect it, but for 120Ah battery it should hold a decent charge for a couple of months without a problem. If it doesn't then the battery has to be suspect.

If the battery is left connected in a caravan then there are often some appliances which might put a drain on the battery. Things like aerial amplifiers, some car type radios need a continual 12V supply to maintain the settings. Some alarm systems might be wired to the battery.

The only sure way is to remove the cables from the battery.

Its certainly a sensible precaution to make sure the battery is fully charged before you need to use it. A solar panel may be just the ticket, or bench charging it, but I do recommend using a smart charger which should prevent you accidentally overcharging the battery.
I'll try and remember to disconnect the battery next time we return from holiday - thanks for reminding me. I agree there may be a drain due to those items you mention.

I'll certainly be pursuing the solar panel option! I expect there is loads of advice in Practical Caravan on these? Is there a particular thread you could recommend on the forum?

Many thanks,
Colin
 
Nov 16, 2015
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Maybe I am old school, I have a lovely old Halfords charger, that I can clamp onto my battery, It doesn't have an amp meter to scare me , it has three lights , 1, to say its on, 2, its charging, 3, its maintaining. The house mains goes off, and come back on , it comes back on again, .
Just want to put it into the caravan this month and get away.
 
Apr 11, 2021
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Maybe I am old school, I have a lovely old Halfords charger, that I can clamp onto my battery, It doesn't have an amp meter to scare me , it has three lights , 1, to say its on, 2, its charging, 3, its maintaining. The house mains goes off, and come back on , it comes back on again, .
Just want to put it into the caravan this month and get away.
I've got a simple charger too. Except mine's got a fast charge/normal charge option, and I still don't know to this day the pros and cons of each!
 
Apr 11, 2021
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A 3 year old caravan battery has been subjected to various stages of charge and discharge over that time, and not always in ideal conditions. The only way to determine its condition is to have it tested.

As for the "green light" they are a gimmick as they tell you nothing at all, apart from the one cell they look at "may" seem to be OK, it has no idea what the other cells are doing !
Thanks Damian. Yes, I have my suspicions about that green light as I had also thought this was too simplistic. What sort of business can test a battery?
 
Nov 16, 2015
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Halfords will check the battery for you, I had mine checked at my last service by the caravan engineer, 96% so its good for another year, or until it fails.
 
May 2, 2021
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Hi all, just thought I'd report back now that I've fixed the problem with the intermittent running of the water pump. Like Nick Andrew above, the fault was the NRV in the water filter housing which was leaking, hence the sloshing noise I could when the pump switched on and off. This was no doubt the water going backwards and forwards through the leaking NRV.

Also like Nick Andrew above, I too now have an impressive collection of Truma spares, which might come in handy in the future.
 
Sep 7, 2020
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Just got back from our second trip with our new Elddis Xplore 304. Ran into a similar problem. Water pump would come on for a few seconds about every minute or so. I also noticed that water was running back into the water container. So I assume its the same problem and I have a service kit due to arrive any day now.

Its a shame I've had to fix a few problems like this myself.

We have a problem with the bathroom basin tap. Initially when the waters connected we cant get any sustained flow out of it. Pump comes on for a second or two then stops. For the first trip we just used the shower head in the sink. When we got home I took the riser off and checked to see if it was clear and it appear to be ok, Put it back on and the water started to flow although the cold has a significantly lower flow rate compared with the hot. This happened again the trip last week. This time took the riser off, put it back on and water flowed although cold still slower rate.

I don't know why there's no flow the first time around but today I discovered the slow cold flow rate is due to the cold pipe tail to the tap being bent through 90degs in such a small space that the pipe is pinched. Not something I can easily fix but will go on my list of things needing to be done under warranty on first service.
 

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