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How a Thermostatic Shower Wall Mount Can Change Your Travel Trailer World

Like most small travel trailers, our Scamp 13’ came with an old fashioned plastic wall mounted shower controller with two clear plastic knobs (the left one labeled H for Hot and right one labeled C for Cold).  To get the right mix of hot and cold water to avoid freezing or scalding, a delicate approach of rotating each of the knobs just the right amount is needed.  We quickly found out on our Scamp 13’ that this was easier said than done!  It usually took some fiddling and a bit of wasted water (and some uncomfortable freezing and scalding water sprays) to get a comfortably heated stream.  And, with multiple people showering, it usually meant leaving the shower on at this setting (with the shower head controller in the position to stop the flow) so that the next person could just jump in without having to repeat the process of temperature mixing (although a trickle would still run from the showerhead in this position).

After several camping trips in our Scamp dealing with this shower conundrum, I decided to do a little research to see if there might be a solution.  The first thing I did was called Scamp to see if the hot water heater temperature could be adjusted lower (since one of the biggest issues was scalding water).  I was told this is not possible.  I later found out that most travel trailer water heater thermostats are preset at the factory and cannot be adjusted!  And, typically, the water heater is set so the water is much hotter than at home because there are only 6 gallons (or sometimes on some trailers 10 gallons) to mix with the cold water (which makes the hot water last longer since less hot water is needed to heat the cold water flow).

After a bit more research, I found the answer – the thermostatic shower valve!  Popular in Europe, thermostatic shower wall mounts offer an amazing solution!  The thermostatic valve mixes hot and cold water to a set temperature and reacts instantly to changes in pressure or temperature of the water by re-adjusting the mix of hot and cold water.  What this means is that you can set your desired water temperature in your small travel trailer shower and forget about setting it again (eliminating the need for manual temperature adjustment)!  Additionally, there is usually an anti-scald safety feature that prevents the temperature from being set too high (red button override for hotter temps).  This is great for families with young children or the elderly who might not be able to properly set the water temperature.  Bar valve shower mounts seem to be the most popular being sold in the U.S. on Amazon.  They are attractive chrome bars (see images) that mount to the wall of your small travel trailer shower.  The temperature is typically set with the right hand knob and the flow rate (from off to higher flow) is usually controlled on the left hand knob.   Most of the bar valve shower mounts I found are produced for the European market and, in turn, have heating measurements in Celsius and 6 inch hot cold water line spacing (instead of the typical 4” spacing found in most U.S. small travel trailers).  This usually means one new hole will need to be drilled in the fiberglass shower wall to accommodate pipes spaced 6” apart.

Because they are primarily designed for Europe, the thermostatic wall shower mounts have parts which may not fit well with parts in small travel trailers built in the U.S.  As such, it’s common for leaks to occur when trying to join the pex/compression fittings in the small travel trailer to the European style thermostatic shower mount if the proper materials and methods aren’t used.  That’s because the compression fittings (like SharkBite) which join the PEX water hoses to the shower mount hardware may not fit properly.  In the case of our Scamp 13’, I found that when screwing down the Scamp’s stock SharkBite elbow connectors on the shower mount’s brass threaded water inputs, the thread patterns didn’t seem to match exactly and the compression gasket wasn’t a good match against the brass.  Even after using plumbers tape on the threads and pipe thread sealant, the connections leaked.  After trying a bunch of different connection types and with the help of my friend and neighbor, Roman, who is an engineer, we found a working solution which did not leak when taking a shower.  Please see below for the steps and materials I used to successfully install a thermostatic shower wall mount in our Scamp 13’.

Step 1:  Gather materials:

1. Thermostatic Shower Wall Mount
2. ½” x ½” FNPT Female Swivel Elbow (2 of these)
3. Metal Worm Gear Hose Clamp (adjustable, 40mm–63mm)
4. White plastic cutting board (2 of these to be safe)
5. Thick plumber’s tape
6. Clear Silicone
7. Hole Dozer – 7/8”
8. Level
9. Blue tape

ALWAYS USE EYE PROTECTION WHEN WORKING WITH TOOLS!  AND, WEAR A PROTECTIVE RESPIRATOR MASK WHEN CUTTING FIBERGLASS!

Step 2:  Disconnect water if hooked up / make sure the on demand water pump is off and release water pressure by running sink.

Step 3:  Remove original shower water mount by unscrewing plastic wall nuts in closet behind the mount.  The shower mount should then pull right out.  Make sure to have a towel to absorb any water coming out of the PEX hoses.

Step 4:  Using adjustable pliers (Irwin Groovelock Plier Set) and with the pliers loose, slap the metal plier faces (top and bottom) with a fast motion against each SharkBite connector end so the connector comes off the PEX, leaving just the blue and red PEX hoses exposed.  Example here.

Step 5:  Wrap each Swivel Elbow brass end piece with thick plumbers tape, push one into the red and one into the blue PEX hoses (should be very tight), and secure it with metal worm gear hose clamps (screw down tightly).  Alternatively, PEX cinch rings, or crimp rings, may be used instead.  Whatever method is used to attach the brass fitting to the PEX, it’s important the joint doesn’t leak.

Step 6:  Cut a straight line on a piece of white cutting board with a wood saw 4” down from the rounded edged top.  We bought several small white cutting boards at Wal-Mart for 88 cents each.  Note:  I first tried with a dremel wheel cutting tool, but the plastic melted leaving a messy surface.  The cut piece will be about 4” long and 8.5” wide, with the rounded edges at the top.  This piece will be used inside the shower directly behind the wall shower mount.

Step 7:  Cut a couple more identical pieces to the above (although having top rounded edges isn’t important) – these two pieces will just be used for spacers in the closet so they don’t have to be that precise.

Step 8:  Assemble the Thermostatic Shower Wall Mount as pictured.  Plumbers tape will need to be wrapped on the brass threads on both sides of the hot/cold brass input fittings (in the opposite direction the pipe will be turned).  Make sure to insert the screen gasket on each side of the mount and rotate the decorative chrome covers over the brass threads.  Be careful not to over tighten the brass fitting on the wall mount side as it could strip the inside threads of the mount.  Hand tightening should be sufficient.  The brass fittings coming out of the wall mount should be uniformly positioned in the same orientation (I positioned them straight out and up).

Step 9:  Place the wall mount over the 4” white plastic back plate piece cut previously and position so that the decorative chrome wall covers will touch the plastic all around when holes are cut.  Mark the position of the holes on the plastic cutting board with a marker using the brass pieces coming out of the wall mount as a guide (the holes should be level and low enough below the rounded top that the decorative chrome covers sit against the plastic all the way around).  Drill the two holes with the 7/8” hole dozer.  Make sure the new backsplash slips easily over the brass fittings on the wall mount.  Make a couple more pieces with the extra plastic cutting board using the original as a template for the holes.  Cut the holes for these two pieces.

Step 10:  Hold the wall mount bar with the right side brass fitting aligned with the farthest shower wall hole on the right and then, with a level sitting on top of the bar, use a marker to trace a circle where the farthest left hole will need to be cut in the shower fiberglass wall.  Be very careful to make sure the holes are aligned horizontally to each other so that the shower mount bar will be level.

Step 11:  Make a dot with a marker in the very center of the hole to be drilled in the shower fiberglass wall.  Then, to protect the area around the hole, stick blue tape down so only the little dot marking the drill location is visible.  Using the 7/8” hole dozer, at very slow speed, carefully drill a hole into the fiberglass shower wall.  There should now be three holes in the shower fiberglass (the center one, used for the stock mount with 4” water line spacing, will no longer be used and will be covered by the backsplash).

Step 12:  Insert the completely assembled wall shower mount with the plastic wall backsplash into the holes in the shower.  Add the two plastic spacer pieces on the brass pipes on the closet side and then screw down the swivel elbows onto their respective pipes (Hot and Cold inputs are marked on the back of the thermostatic wall shower mount), using a level on top of the mount to ensure it is level when firmly attached.  Note:  the original wall nuts are no longer used as they block too much of the brass threads.

Step 13:  Now that everything is complete and attached, the system needs to be tested under pressure.  It’s good to have someone standing by the closet and shower inspecting the joints while another person turns on the hose hookup.  As the system is pressurized, inspect for leaks on both the PEX side and shower side of the system.  Hopefully, there won’t be any leaks.  However, it may be necessary to tighten down the nuts on the wall mount if you see some dripping.  Once satisfied the system is holding pressure and there are no leaks, apply a bead of silicone all the way around the backsplash inside the shower (and also along the outside of the spacers in the closet) to prevent water from leaking behind the backsplash into the closet.

Step 14:  Fill up your hot water heater (if not already filled) by running the Hot water in your sink until water comes out.  Then, turn on your water heater and wait until the water is hot.  Take a hot shower!  Inspect again for leaks.

I did reposition the wood block that holds the PVC coat hanger because it was right in the way of the PEX piping and wasn’t allowing flexibility in positioning the PEX.

With a bit of preparation and care, it is possible to have a reliable thermostatic shower wall mount in your small travel trailer!  And, once you are all set up, you will likely enjoy much more comfortable showers and save some water too!  After you try a thermostatic shower valve, you probably will never want to go back to mixing hot and cold water manually in your small travel trailer again!

 

Disclaimer:  You will get the same great Amazon price by clicking on the links here compared to buying directly on Amazon, but by buying here you will also be supporting the continuation of this website as we get a small commission from each sale.  These are products and procedures we use for our own Scamp that we selected and developed from our own research and experiences.  However, we do not endorse any specific product and cannot guarantee that the products we use are exemplary and the procedures we use are complete, accurate, detail the correct recommended procedures, or apply to your model small travel trailer.  It’s always best to double check with your manufacturer or operation manuals to ensure you are doing everything correctly.