Fresh water being dumped - how can I stop it?

I have a Nuevo ES (4 berth) 2022
First winter away in it. I am filling up the fresh water, but as soon as I switch on the water pump symbol on the control pad (to enable me to use the taps indoors), the van is dumping all my water. 
I have switched on the 'Tank Heater' via the settings on the control panel, even though I don't think its cold enough to need them and I have set the water heater on to heat the water.
But each time I switch the water water pump on, it is dumping my water in a wave coming out of the driver side to the right of the whale inlet - Can anyone advise how I stop this please??

Be grateful for any suggestions/help 

Cheers x

Hi and welcome to the forum 

https://www.autosleeper-ownersforum.com/f36-asof-welcome-section-new-members-please-introduce-yourself-here

Close hot water tank dump valve, see op manual

Just looked at the AS website - the 2022 handbooks have been written generically and leave a lot of detail out that will be in the (supplied) Truma information.  From an older handbook for a Nuevo see below - this is what you are looking for:

I thought 2022 was Whale system and dump valve is yellow, not the blue fitted to Truma systems. May be wrong but thiink I have seen several threads about this on various fora in past couple of weeks

Hi, Sounds like your frost protection valve has clicked open. press in the button and turn knob on top 90 degrees until it clicks closed. Problem should be solved.

WANDERING DAVE wrote:Hi, Sounds like your frost protection valve has clicked open. press in the button and turn knob on top 90 degrees until it clicks closed. Problem should be solved.

I see your van is 2022, so do you have Truma system?  What you describe is Truma.

Paul
As you have asked first is it a truma or a new whale system that’s having lots of problems then it can be explained what to check

Just to clarify what the others are trying to say.

Your boiler will have a valve that opens automatically if the temperature inside the van falls below a set level - could be anything below 7°. This prevents water freezing inside the boiler - very expensive to fix.

It sounds like this has tripped, so, when you turn on your water pump the system is trying to fill the boiler, only the valve is open, so water is running straight through it, emptying your fresh water tank in the process.

Your tank blanket will not affect this in any way.

As has been said, if you confirm which system you have, you'll get advice on how to close the dump valve.

The A-S website still shows the Nuevo as having the Truma Combi.  The OP's symptoms perfectly match the Truma frost dump valve being open which it will be if the internal temp has dropped to 3 degrees or lower.  It can only be reset by pushing the button back in when the internal temperature has risen to 7 degrees.

Can't be much of an issue, OP hasn't been back on forum since posting  message last year

Probably posted on multiple forums and got the same answer elsewhere, so, didn't bother to check back here.

Thank you for your help all - resolved, once I found where the thing was housed 

It was the boiler drain switch that had tripped as most of you suggested- cant understand why this is not in the manual online

Cheers x

Helen Robertson wrote:Thank you for your help all - resolved, once I found where the thing was housed 

It was the boiler drain switch that had tripped as most of you suggested- cant understand why this is not in the manual online

Cheers x

A-S put little effort into their manuals.  The current manual states on page 7-1 "If the vehicle is not being used during freezing conditions the water should be drained.  If the vehicle is being used in such conditions, refer to section 9 for details of the automatic draining of the heater and use of the water tank heaters."  If you go to section 9 it only repeats "If weather conditions are below zero centigrade and the motor home is not being used for habitation the water heater and water system should be drained." and it describes an older water tank heater that isn't fitted to the EC700 models.  However, if you look at section 9 of the older 2018 handbook (and why should you if you have a 2022 model!)  the frost control safety/drain valve is explained on page 9-16 as it is in the Truma Combi(E) Operating instructions on page 18.  The tank heaters fitted to EC700 models are only explained in the Harmony UMS User Instructional Handbook.

The frost control safety/drain valve should have been covered by the dealer on handover but I can well believe it wasn't.  This is an example of why this Forum is invaluable.