Where is it?

Hi. Need some help. We've got a 2020 Warwick XL and have a water problem. Prior to going away last week I filled up with water and bled the system. When we got on site I found nothing in the hot taps so needed to purge the air on that side (cold side was fine) For the rest of the day things were OK, overnight we turned the pump off and left the water heater on like we always do. Next morning the boiler must be empty because no water in hot taps again and the heater had cut out so had to be reset. So basically if we leave the pump on things are fine but if we turn it off that's when the boiler drains

Now, I know for sure, there's no water leaking from the boiler drain off under the van and there doesn't seem to be any water leakage inside the van. So I spoke to AS technical and they are pretty sure it's the non return valve (NRV) so that means water is draining from the boiler back into the fresh tank.

The van is in storage at the moment so I'm hoping to get over sometime this weekend to search for this non (NRV) so I would very much appreciate it if anyone could tell me where I can find it, apparently it's blue and about 3" long.

Thanks for any help

It sounds as though you have the Whale system in which case you will have either 1 or 2 NRVs.  If it exists, one will be next to your Truma drain valve and the other will be integrated with your Whale pressure switch.  I assume you know where both of these are.  If both NRVs are working, no water should find its way back into the freshwater tank.  However, I suspect if the pump is switched off and the water pressure drops as it cools, the likelihood of the NRVs allowing water to pass backwards through them increases with time.  The NRVs will also do this if grit gets in them.  This is particularly so for the Whale pressure switch NRV which can be dismantled for cleaning.

You could follow the well trodden path of replacing the Whale pressure switch & NRV and the Whale submersible with a Shurflo diaphragm pump protected with a removable gauze filter.  It has an integrated pressure switch that shouldn't require adjustment and it doesn't require an NRV as water should only pass through it in one direction when the motor is running.

Caraman wrote:It sounds as though you have the Whale system in which case you will have either 1 or 2 NRVs.  If it exists, one will be next to your Truma drain valve and the other will be integrated with your Whale pressure switch.  I assume you know where both of these are.  If both NRVs are working, no water should find its way back into the freshwater tank.  However, I suspect if the pump is switched off and the water pressure drops as it cools, the likelihood of the NRVs allowing water to pass backwards through them increases with time.  The NRVs will also do this if grit gets in them.  This is particularly so for the Whale pressure switch NRV which can be dismantled for cleaning.

You could follow the well trodden path of replacing the Whale pressure switch & NRV and the Whale submersible with a Shurflo diaphragm pump protected with a removable gauze filter.  It has an integrated pressure switch that shouldn't require adjustment and it doesn't require an NRV as water should only pass through it in one direction when the motor is running.

Thanks for replying to my question mate. I know where the pressure switch is but not sure how to get to the NVR, is it fairly obvious?
When looking at the boiler (yes it is a Whale) I haven't noticed a valve there, is it under the drain valve tap?

Maybe they just forgot to fit one like my on van 

The lack of one hasn’t caused any problems in 4 years by the way.

This should help with the Whale pressure switch/NRV and its not blue:

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As Dbvwt has intimated, I wouldn't worry about the other NRV which not all A-S's have.  

This water flow schematic shows the location of both NRVs from which you can see how the Whale water system (less the Whale inlet to the freshwater tank) should work:

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That’s brilliant mate, thanks