Water System on Tribute 670

There is an irritating feature on the water system for the Trigano Tribute 670 which may well have been intended to protect the boiler from frost damage but ends up being a severe pain in the you-know-what. I’m talking, of course, about the Truma automatic frost protection device located under the bench seat close to the boiler.   The intention is that, if there is the potential for icy weather, the device activates and empties the boiler of water to save it icing up and breaking.  

The original Truma automatic boiler protection valve

The problems with this are:

  • It is set at too high a temperature so dumps the water well before any danger of frost.  
  • It is difficult to reset – if the temperature doesn’t rise significantly the valve cannot be closed
  • It is bulky, preventing the installation of anything but the smallest leisure battery.
  • If the pump is left on then it empties the whole water system and as the pump keeps on running when empty there is the potential to damage it.
  • It can potentially leak – we found that during the night there was an intermittent burst of the pump running for less than a second.  We think we have traced the problem to this device

I’ve been looking at a remedy for some time.   A number of people have tried to jam the device closed with wedges, clothes pegs and suchlike.   My feeling is that the device itself is unnecessary.   Most competent motorhome users know it’s a good idea to drain the water system when the vehicle is unused over the winter.   If using the motorhome in the winter most of us will probably use some form of heating to keep the vehicle above freezing.   The problem is that this device is situated at the lowest, coldest point in the motorhome and will therefore activate well before frost becomes a problem.   

We found this once when travelling in Holland.   We were comfortably snug on the campsite with mains power providing energy for low level heating.   We were woken in the middle of the night with the pump emptying everything onto the grass.   By the time we had groggily switched off the pump and tried unsuccessfully to reset the device all our water was gone.   It has happened more than once.

The Solution:

If you feel halfway competent there is an easy way to replace this bulky nuisance – fit a manual dump valve.   The part I got was from Caravanparts.co.uk.   It cost around £36.   You may be able to get it cheaper elsewhere.   The Truma part number is 70142-05. It looks like this:

Manual boiler protection dump valve – John Guest fitting

This is the process.


  1. Clear space around the bench seat including removing the table and cushions
  2. Empty the space under the bench seat of all the stuff that you’ve put there since you bought the van – most of which you may never have used.
  3. Remove the battery.  You are working with water next to a powerful electrical supply – you have been warned.


  1. Place an old towel or similar around the valve.   No matter how careful you are water will leak out and you don’t want it sloshing about in that space.   It also helps to stop screws, collets and other small bits rolling away under the boiler or between the wood floor and the van floor.  Believe me they will disappear if you don’t. 
  2. Undo the two screws holding the old unit to the floor.  Put them somewhere safe and remember where you have put them.
  3. Insert a small flat head screwdriver under the horizontal part of the retaining clip and lever out the clip. This releases the actuator from the pipework.  Withdraw the dump valve from its position – you will notice that it either brings with it, or leaves behind, a clear plastic drain tube.   If the tube remains behind then you can fit the new unit straight onto it.

  1. Remove the adaptor joining the pipework.   This is where it gets interesting.   The connectors on the pipework for this motorhome are all ‘John Guest’ fittings.   They are ingenious but not easy to figure out.   Luckily there are videos like this on YouTube to show you how it’s done.   They are essentially push-fit connectors with a locking ring which stops them coming loose.  The locking rings are secured by little red plastic collets.   
Locking ring collet
  1. Remove these little red clips and put them somewhere safe.  I lost one of mine and had to buy a new set of ten from eBay.  If you lose yours I have nine for sale.
  2. Push the locking ring towards the body of the connector while simultaneously pulling on the water pipe you are trying to remove.   It takes a bit of practice but eventually you feel the pipe coming out of the connector.  Do this for both sides and this will release the the adaptor and leave you with two ends of blue 12mm water pipe.


  1. The replacement process is very much the reverse of removal.
  2. Push both pipes into the connectors of the manual valve.  Push them hard.   Then harder.   You may think you have them firmly seated but they seat in two distinct phases.   The second phase – another quarter of an inch – is crucial in sealing the connection.   (I found this out by trial and error.   The first – boiler side – went in easily and I could feel it seat and then grip as I pushed it further.   The second – delivery side – is a short piece of pipe at a ninety degree angle.   I thought I had pushed it in far enough but when I turned on the pump water went everywhere so I had to start again).
  3. Test your connections.   Add some water to the system and start the pump.   Keep your hand on the pump switch until the system gets to full pressure.   If there is any sign of a leak switch off the pump immediately and let the pressure drop away.
  4. Slide the little red plastic collets back onto the locking ring to ensure the connection stays sealed 
  5. Screw the new valve to the floor using the screws you have carefully saved earlier.
  1. Replace the battery if you removed it (RECOMMENDED) and reconnect the power leads.
  2. Put back most of the stuff you took out, replace the bench seat lid,  cushions and table.   Run the system up to pressure and open the taps to remove any air.   Make a strong refreshing cup of tea and congratulate yourself on a job well done.


I would always check the new valve a few times over the next few days. Even the smallest leakage can result in the wood floor rotting or the van floor going rusty.   Check the dump valve works by pushing the yellow lever to the vertical.  Don’t forget to put it back to the horizontal when you have checked it.   All you have to do now is remember when winter is coming, to drain the boiler and leave the yellow lever in the vertical position.  Happy camping!

WARNING:  Whether you replace the valve or not, from our experiences it is ESSENTIAL that you turn off the pump whenever the motorhome is unoccupied – even if going for a walk.  That way you are unlikely to return to the van to find it sitting in a puddle of your discarded water supply.

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