What is this drain/Pump failure

Hey gang,
So our submersible water pump may be goosed - and I’m doing my research to troubleshoot. 

We were awoken by the pump continuously running at 5am! It was apparently -8 outside, so I immediately suspected the frost valve - but no, van was warm and the valve was still closed. Opening taps produces no water though. It was our last night and we had a container of fresh water, so just switched off pump and back to sleep!

I’ve been reading a lot of threads tonight, so intend to go check as many connections as I can find tomorrow, not least in the toilet swing wall. 

One thing has specifically confused me though. When I looked under the van this morning, there was a nice frozen puddle under the van. It was relatively small, humped, with an indentation directly below what looks like an overflow/drain pipe, which I guess is under the Truma Combi 6 E. It is NOT the drain for the frost valve - if I open that, I get to see the water flood all over the gas tank. This cleanly drops to the ground. 

I’m sure it’s not something that should be continuously dripping and may or may not be connected to my pump problem. 

If I can’t see anything to rectify, I am of course tempted to follow the herd and fit a Shurflo - but crucially I don’t want to do this if the problem is elsewhere in the plumbing!

Pipe in the photo is black on white, to the right of the spare wheel. 

All help appreciated!

Heeb

Heeb,

If you look at your Truma Combi you will see the hot water outlet pipe and at the same point on the Combi you will also see a clear plastic pipe that runs down through the floor.  In your case water has leaked through this pipe which shouldn't happen.  The pipe is a vent tube for air to pass into the hot water tank when the Truma drain valve is opened i.e. when it is depressurised.  It appears that the vent pipe junction on the side of your Truma, referred to as an aeration valve, has failed probably because it's got some grit in it.  The simple solution is to replace the aeration valve but removing and cleaning it might help.  

The other day Peter Brown posted a photo of the aeration valve in this thread:

https://www.autosleeper-ownersforum.com/t45058-drain-tap

It's possible that the water in your hot water tank cooled overnight causing it to contract and make the water pressure drop. When this happens the pump should come on briefly to restore the pressure.  If it was -8 degrees its possible that the pump was unable to restore the pressure either because as you say its goosed, or, because the external water was freezing.  I wonder if you had your freshwater tank heater on and if you did if it was working properly.  A couple of years ago on my 2019 van I discovered mine wasn't working properly because it hadn't been wired correctly (or tested!) in the factory.  See this thread:

https://www.autosleeper-ownersforum.com/t40487-tank-blankets?highlight=Tank+blanket

Thanks for this!

First off - I have running water today!? I had actually put on the freshwater tank blanket last night, so that might have sorted the issue if, as you suggest, the water was frozen and it simply couldn’t draw anything in!

That said, I’ve just read through tour marathon tank blanket journey (very well done for that level of investigation & patience!). I’ve not yet checked the EC700 connector block, but last night I had 0% in the waste tank. We’re up to 4°C here (ignoring windchill Feels Like of -3°C), so it may have thawed itself? I don’t have a clamp meter, but couldn’t see a flicker on current draw on the control panel whilst switching the blankets off and on. I filled waste to >25% and tried again - still no flicker. Think I’ll try using my multimeter across the fuse to see if anything’s happening (once the temp drops - although CP read -3). 

I am going skiing in the Alps for the first time this year and intended to do the waste>>bucket method, so I really need the freshwater to work independently. That said, I’m now alarmed to read the heaters only work on EHU - who decides these things! And now if the freshwater tank froze - whilst internal heating is on, so boiler good - how long would it take to defrost once I got on EHU if I have the pitiful power readings you initially found!?

That valve. Can I just disconnect and give it a rinse? Gonna guess I need to drain it all down first if it’s under pressure.

Heebson wrote:Thanks for this!

First off - I have running water today!? I had actually put on the freshwater tank blanket last night, so that might have sorted the issue if, as you suggest, the water was frozen and it simply couldn’t draw anything in!

That said, I’ve just read through tour marathon tank blanket journey (very well done for that level of investigation & patience!). I’ve not yet checked the EC700 connector block, but last night I had 0% in the waste tank. We’re up to 4°C here (ignoring windchill Feels Like of -3°C), so it may have thawed itself? I don’t have a clamp meter, but couldn’t see a flicker on current draw on the control panel whilst switching the blankets off and on. I filled waste to >25% and tried again - still no flicker. Think I’ll try using my multimeter across the fuse to see if anything’s happening (once the temp drops - although CP read -3). 

I am going skiing in the Alps for the first time this year and intended to do the waste>>bucket method, so I really need the freshwater to work independently. That said, I’m now alarmed to read the heaters only work on EHU - who decides these things! And now if the freshwater tank froze - whilst internal heating is on, so boiler good - how long would it take to defrost once I got on EHU if I have the pitiful power readings you initially found!?

That valve. Can I just disconnect and give it a rinse? Gonna guess I need to drain it all down first if it’s under pressure.

It's deliberate that the tank heaters will only work on an EHU (with the PX300 on), or, when driving. They would flatten the LB otherwise.

I've not had any trouble with the aeration valve on my Combi so no experience of removing or attempting to clean it.  Clearly the pump will need to be off with a hot water tap open to depressurise the water.  Maybe open the dump valve to lower the level in the hot water tank below the hot water outlet.  It should be simple enough to remove.  For cleaning I suggest forcing mains water back through the aeration valve in the direction the air should go and possibly using something that breaks down calcium deposits.  It's worth a try but fitting a new one won't break the bank if that doesn't work.

I knew there was another question I had for you! 

Do you know where the pressure switch for the freshwater tank pump is located in the Neuvo? That was something I thought I might have to play around with here, but be good to know for future reference. I had a good look around - and stuck the phone camera where my head wouldn’t go - but couldn’t see it. (Can see the one on the sidewall for the external Whale filler.)

Re. the blankets on battery. I can easily see a scenario where I’m parked somewhere sub-zero for the day/few hours, but planning on EHU overnight, where I’d be willing to hammer the LB for a few hours. With today’s Lithium batteries, that becomes more feasible. It’s just strange to me that they remove the user control - there’s plenty of ways for someone to flatten their LB. 

Don’t suppose there’s a way to fool a EC700 to think it’s on EHU!?

Think I’ll just be ordering a new NRV and vent tube (once I’ve assured myself replacing the latter won’t become a mare!

Truma don't call it an aeration valve but that does describe precisely what it does.

The valve was stuck closed when I got the van, the dealer sent me a replacement but it was a compression seal to the boiler, not the John Guest version that our vans need and it wouldn't seal properly.

You can test the valve easily by removing the elbow from the van, putting a finger over the hot water out connection and blow/suck at the combi connection.  You should be able to suck air out but not blow any in.

When I investigated the original unit, the fault had cleared so I refitted it.

Beginning of this year I found it had gone faulty again so obtained a replacement from Prima Leisure.  When I came to drain down a couple of weeks ago I found that the valve was stuck closed and the boiler wouldn't drain.  I asked Prima to replace it but they wouldn't as I'd had it over 6 months.

I contacted Truma and they advised that it had a 2 year warranty and asked me to email them details.  I did that a couple of days ago and am waiting a response.

Peter Brown wrote:Truma don't call it an aeration valve but that does describe precisely what it does.
....

Truma in their Combi installation instruction describe as a:

"Hot water connection Elbow fitting (with aeration valve) – push-fit 12 mm"

They describe the plastic pipe that connects to the aeration valve and passes through the floor as:

"Venting hose, external diameter 11 mm"


When I queried the purpose of it with Truma last year they said:


"The valve you refer to lets air into the tank as you drain the water through the drain valve. If you find it was water coming out of it when the drain valve is closed you would need to replace the hot water elbow."

The reason I queried it with Truma was that some folk on the Forum were wrongly describing it as the pressure relief valve which it definitely is not.  The Truma frost/drain valve is the pressure relief valve.

Heebson wrote:I knew there was another question I had for you! 

Do you know where the pressure switch for the freshwater tank pump is located in the Neuvo? That was something I thought I might have to play around with here, but be good to know for future reference. I had a good look around - and stuck the phone camera where my head wouldn’t go - but couldn’t see it. (Can see the one on the sidewall for the external Whale filler.)

...

The Whale pressure switch and integrated Non Return Valve (NRV) is screwed to the floor under the EC700.  You might just be able to reach it by removing the plastic ventilation grill in front of the EC700 in the o/s seat/bed locker.  When mine was playing up the A-S Service Centre moved it in front of the plastic grill so it could be adjusted more easily.  Since then it's been removed all together and replaced with a Shurflo.

@Caraman - I pretty certain I have the same tank heating mat snafu as you

Using the multimeter across the fuse, I can see a current increase, but only when the wastewater mat is lit-up. Freshwater on its own does nothing. W+F, get a current; W only, get a current. I then noticed that the sensor was playing up and wastewater was now showing <25% (I had not drained from earlier), so suspect they are flipped too. 

I’ve raised a ticket on Sargent’s Helpdesk to see if they’ll send me a harness/adapter too. 

Might just order a cheap clamp meter!

It drove me to buy a DC clamp meter which is the only meter I carry now and is quite useful.  A multimeter across the fuse holder will show how much current is flowing but it won't show which heating pad is receiving it.  You will see from the long thread it was a voyage of discovery for me!  The chap I dealt with at Sargent was Cristian Lazar - Cristian@sargentltd.co.uk

Heebson
As Peter & Caraman have discussed, you might be better just changing the elbow fitting for the £20odd quid, I got caught out last year on same fitting on old van,it was 5yr old and the little plastic grippers on the insert were brittle with being on the hot outlet and lost one when took off for descaling/cleaning
Cheers Sheppy

Heebson wrote:...
I am going skiing in the Alps for the first time this year ....

Heeb,

This is off topic but I couldn't hep noticing your VancoCamper summer tyres.  Are they legal in the Alps in the Winter?

Caraman wrote:

Heebson wrote:...
I am going skiing in the Alps for the first time this year ....

Heeb,

This is off topic but I couldn't hep noticing your VancoCamper summer tyres.  Are they legal in the Alps in the Winter?

Good spot! That’s the spare - I got winter tyres fitted to all four wheels last month. Obvs hoping I won’t ever need the spare

Heebson wrote:

Caraman wrote:

Heebson wrote:...
I am going skiing in the Alps for the first time this year ....

Heeb,

This is off topic but I couldn't hep noticing your VancoCamper summer tyres.  Are they legal in the Alps in the Winter?

Good spot! That’s the spare - I got winter tyres fitted to all four wheels last month. Obvs hoping I won’t ever need the spare

Ah - so they will be VanContact Camper tyres?  I've just pushed the boat out with slightly larger 225 Michelin Crossclimate Camping tyres.  It was a struggle discarding 6-year old tyres with so much tread left. Like you I have retained the VancoCamper as a spare.

I was given nearly two new commercial van winter tyres (stickers on the tread hadn’t even been worn thru) from a friend. Couldn’t source another two the same, so after much agonising, went  for Continental VanContact Winter (215/70 R15 109/107R) 73CB on the front. 

Really painful getting rid of the old tyres! Going to be equally painful to getting tyres flipped twice a year - but I’m assuming if I store them properly, I’ll get a lot more than the recommended 5yrs out of them…

Heebson wrote:........

Might just order a cheap clamp meter!

Beware. 'Cheap' clamp meters usually say they measure up to 10A. Even in some descriptions they say AC and DC. But in reality they only detect AC unless you can see a separate switch position on the dial for DC. I and many others have fallen foul of this, we in the motorhome world would normally want to read DC more than AC.

As for following the herd and fitting a ShurFlo, here's my story.
Some years ago I was friendly with a chap that used to be a director of Swift caravans. He told me that Whale did a study of caravan users and found that on average, the caravan users go away for two weeks in the summer plus three long weekends - bank holidays - in a year. Therefore they designed their submersible pump to last that long. 23 days use. This fulfills their statutory duty to offer a one year warranty on the pump. This makes them very cheap to manufacture. So cheap that my director friend told me that if a customer goes into a caravan dealer with his dead pump, the dealer should just reach down into the bin of new pumps under his desk and hand one over without asking any questions.
This is the reason that most motorhome users fit a Shurflo. It is one of the first jobs I do when I get a new wagon, if it doesn't already have one. You don't need to remove the Whale from the tank, just add the Shurflo in series and divert the power wires from the Whale to the Shurflo.

I've read through a lot of very relevant stuff in this thread, but I've not seen anyone mention that in very cold weather, if your battery charger is not on, the output from your very cold battery may not be sufficient for the 'system' to realize that the pressure in the water tank is high enough and it can stop powering the pump. We often get this in our Bourton at night if we are not on electric hook-up and we switch the pump off on the panel to get some sleep and prevent the pump from wearing out. I would hope that newer pumps may have hardware/software to detect that the pressure is ok and be able to signal that back to the control system, but I doubt it.

You should be able to solve your problem by adjusting the pressure switch:

It may be that Delboy's pressure switch needs adjustment but it's well documented that the correct Whale pressure switch setting is sensitive to voltage which I think is the point Delboy is making.  Another solution is to fit a Shurflo.

After 18 years and 4 vans with diaphragm pumps and 2 years with a van that has the whale submersible, I very much prefer the whale system in operation whilst recognising its much more difficult to replace if it fails.

Delboy wrote:I've read through a lot of very relevant stuff in this thread, but I've not seen anyone mention that in very cold weather, if your battery charger is not on, the output from your very cold battery may not be sufficient for the 'system' to realize that the pressure in the water tank is high enough and it can stop powering the pump. We often get this in our Bourton at night if we are not on electric hook-up and we switch the pump off on the panel to get some sleep and prevent the pump from wearing out. I would hope that newer pumps may have hardware/software to detect that the pressure is ok and be able to signal that back to the control system, but I doubt it.

So far as I am aware the Whale pumps are simply very small submersible centrifugal pumps, identical to the small bilge pumps that one might fit in a boat. They are not a positive displacement pump. They only achieve much lower pressures. In bilge pump applications the usual problem can be that they struggle to lift a head of water sufficient to get the water up over the gunwhale. I for one was very surprised to find that this sort of pump is being used in a domestic water pressure system.

So if the battery voltage is the slightest bit low, and/or if the wiring is at all undersize (hence voltage drop) then the pump will struggle to develop enough pressure to trigger what must be a very sensitive pressure switch. We had the same symptoms in our van before I fitted a Shurflo. The pump just couldn't (quite literally!) "stir up" enough pressure unless the operating conditions were perfect with plenty of volts arriving from the battery, which of course would be the case if the van was on EHU charge but perhaps not if camped wild.