Drinking water on board

[Redbillie]

Hi. We are new to motorhoming, having just purchased our first motorhome. We are getting it ready to travel and yeaterday filled the water tank and water heater. Everything worked great. The heating worked and the water ran freely. We locked it up for the night, leaving the electrics switched on by mistake. This morning, we heard the water pump going and went in to find the water tank was empty. All taps were off. My question is, where did all the water go?
Thanks.

 

[TonyJones]

There's probably a drain tap on the fresh water tank, typically just underneath, on the same side as the filler.
Dealers often leave them open on delivery, don't know why!

 

[gjh]

Another explanation may be that cold overnight temperatures caused the automatic dump valve on the hot water tank to open. In some vans (not all) that draws water from the cold tank until it also empties.

Graham

 

[Redbillie]

Thanks Tony. I'll check with the dealer.

 

[Redbillie]

That sounds more likely Graham. It was cold that night. ❄️

 

[gjh]

From memory, I think the auto valve opens at about 4 deg C but can't be closed until the temperature is 8 deg C at the sensor unit. The valve shouldn't open if the water heater is in use.

It's always best to drain down the water system completely when cold weather is expected. The dump valve will protect the water heater but if water in the taps freezes it could damage them. A tip I picked up from Don Madge is to take off the shower head and blow down the hose to empty it of water before leaving it laid on the shower tray to allow any residual water to drain. It is also a good idea to run the pump momentarily with the taps open to clear the system and to operate the toilet flush if it takes its water from the main tank.

Graham