top of page
  • gscalfaro

Truma Combi 4 eco plus install and more

Updated: Feb 9, 2023

It has taken a while to get here, I purchased the Trauma Combi when my van was on order, that was right before Covid hit in 2020. Some issues with the Van and family health issues got in the way of things, but I am back on track. I purchased the unit from This was not an official Truma dealer, instead he had purchased the units at asset auction. They were very upfront about this, the caveat to purchasing the unit through them, is you had no warranty from Truma. The site is now and they no longer have any Truma units in stock.

Seeing that the Trauma Combi is a combination heater/water heater I needed to get the water system installed also. I purchased a 21-gallon tank from RecPro. The unit is 39” x 16” x8” and is being installed behind the rear wheels.

The tank has four fittings: drain, inlet, output to pump, and vent. I put a check valve right after the water gets into the van interior. This allows this section exposed to the outside of the van to be drained when using in cold conditions. For the water intake, I used a nice clean water inlet for the van by Aquor Water Systems .

Being the unit is propane/electric I also needed an intake/exhaust vent. The only problem with this vent, is that gas station attendants try to unscrew it thinking it is a gas cap. I guess only a problem in states where you don’t pump your own gas.

The combi system requires a pressure regulator, quick drain valve and check valve for install. It ends up being a PEX plumbing puzzle. I conveniently (actually, it is not so convenient) a fuse panel on this side of the van. The kit came with all the pieces and adapters needed. I have the water lines plumbed for the connection kitchen faucet and shower valve. The drain connection will connect to the HepvO waterless waste trap.

The next move was to cover the mess up. For my interior I chose to go with painted marine ply, and I put a maple face frame, the draws are inset in the frame. Of course, the undermount drawer slides I wanted are all on back order, but I didn’t have time to wait.

After the that was installed, I wired up the water pump, and Truma Combi. It has the 120-volt, 12-volt, temperature probe and control panel connections. I used a Smart Switch from, I will go into more detail of them in a later post.

Now for the test run I just need to hook up the control panel. I threw together a quick bracket to hold it until I come up with a final location.

Being that you can’t find a RV undermount propane tank for sale at this time, I am testing with just electric. The unit has 5 energy modes:

LP gas

LP gas


Electricity 850 W+ Gas


Electricity 1700 W+ Gas

EL 1

Electricity 850 W

EL 2

Electricity 1700 W

Anyhow currently all systems are a go, with testing the heater. The thing is crazy quite, admittedly I don’t have the propane burner firing up. The other great thing is that I will have four individual ducks, front of the van, underneath shower, sink cabinet, and back by the bed. No more hot spots in the van.

I throw the sink top on for a quick test fit and hook up the connections. The sink and faucet were found on amazon, OWOFAN Kitchen Faucets and STARSTAR Workstation Ledge Undermount Single Bowl. I still need to hook up the shower, and some other finish stuff (move electrical outlet over) , but now I can tell the wife we have indoor plumbing.

I also added some side cabinets, along with upper storage cabinets. It is time to take it out on a test run.

23 views0 comments

Recent Posts

See All


bottom of page