Oxygenics Fury RV Handheld Shower head --COLD drip

I believe its normal, why do not know. Our Oxygenics did not have any type shut off so installed on between hose and head. When turning the water off at the shut off and back on there is a blast of cold water. 

I think, but am not sure, it has something to do with water pressure. The reason I say that is if I remember correctly, its seem that when on water from holding tank (pump) I do not have the cold water issue. 

They don't completely shut off. I have not had an issue with mine being cold in the pause setting. I have read elsewhere that they don't turn off completely intentionally, as it keeps the hot/cold mix that you want constant. Of all the shower heads I have had with the pause feature none have ever completely shut the water off.

I had the same issue in our Northstar 12STC truck camper.  When I would turn off the water with the shutoff, the dripping water would change to straight cold, and an initial blast of icewater when I turned it back on.  I was able to stop that by installing a thermostatic mixing valve similar to this.

You set the temperature you like on the mixing valve, and it will let only water from the hot water tank pass until it reaches your preset temperature, then will start mixing in cold water to maintain that temperature.  It wasn't hard to plumb in, basically you run your hot and cold water lines to the mixing valve, and only one line from the mixing valve to your shower faucet.  I plumbed mine to the hot water side of the shower faucet, so the cold water handle does nothing anymore.  No more cold water dripping or blast of icewater.

Here it is plumbed in my camper.

We used to have the issue also, and while we now have the Oxygenic, the same problem of cold blast happened on the OEM one that did not 100% shut off either. 

I did solve the problem by installing a positive shut off at the hose fitting on the shower faucet.  We boondock a lot and cannot afford to waste water.  We do navy showers as it is sometimes called, wet yourself, shut water off, soap up, rinse, shut off, shampoo hair, then final rinse.   I had to find a brand that was 100% shut off and did not leak and would  fit in the space.  I had to unscrew the faucet from the wall, spin on the new valve, put faucet back on then put the hose on. 

Short of buying a new RV....LOL. here is the issue with the cold blast and leaking shower.  Or at least one explanation on why.     I'm assuming your camper has a tank type water heater that uses a one 3 way selector valve on the bottom cold water inlet, and a check valve and T on the top hot water outlet of the water heater as part of the winterizing kit.  Yes/no?  Assuming the answer is, yes, here is what can happen on that little drip.

The little drip  is a small leak in the midst of a pressurized water system.   This effect can happen  when using city water or onboard tank water and pump.    The drip is a very small flow, but yet it is flow and the shower head is open to both the hot and cold water faucet.   That drip flow will come from the water pipe with the least effort to allow the drip flow.    Now enter the water heater discharge check valve.  That check valve has a spring loaded normally closed poppet check in it.  That spring may have 2 or 3 lb (etc)  of force holding the check valve poppet closed.    When the dripping shower head wants to drip water, the water flow it will come from the water pipe with the least resistance to allow a drip of flow.  The cold water pipe has no check valve and even if there is only a small difference in pressure drop to get flow, the cold water pipe wins as the flow is smaller then the larger flow which is needed to allow flow to open the hot water check valve when both the hot and cold faucets are open.   To get more technical on this, we need to look at all the pressure drop places in the camper. If the cold water pipe had lots more elbows and other restrictions in the water line, then the spring force of the hot water check valve, then hot water line would win and it would drip hot water or a blend of hot and cold.

If you change the winterizing kit to a two, 3 way valve setup, it gets rid of the spring check. That might change the water drip to be a little more warm of a blend as now some hot water can blend with the cold in the amount of the water the size of a drip.    How much blend will come from how many elbows and other restrictions are on each hot and cold water line.   

Fiddling with getting a positive on/off valve that works at the shower faucet may be the easier fix.

If you want, I can get a pic of my shut off and maybe the brand.  It was a store generic brand out of Menards Lumber yard. 

Hope this helps

John 

I have had a similar problem as some of you but once was met with a blast of full hot water. Scalded my chest. Ever since I take the wand and point it toward the wall until temp normalizes.  Full hot or cold blast is no fun either way and can be downright dangerous.  I think it's an RV problem as it's been the same for every RV I've owned.