What you are describing sounds normal. The water in the lines from the water heater to the shower head are not insulated and will cool quickly.
Does your shower head shut off fully or still run at a trickle?
This is normal operation. A simple solution.....rather than turn the shower head completely off, let it dribble while you soap up. It will stay hot.
Or...don't keep you water heater on. Just fire it up for the shower only heating it ti your desired temperature. This way only one faucet is turned on, no opportunity for the water to "slide" through the faucet. Depending on how long the water is shut off there will be a bit of temperature drop. Really not a big deal though it is more pronounced when it is cold.
We use a wireless meat thermometer probe inserted into the insulation next to the water tank to obtain a temperature.
We mostly boondock and this procedure also reduces water usage. With the Oxygenics showerhead we only use a total of 2.5 gallons of water for both of us to shower if we are mindful.
Any other domestics hot water demand is taken care of by simply heating it on the cooktop, another boondocking water saving protocol.
We have a Oxygenics shower head that allows for some water to trickle through with the shutoff mostly closed, but it immediately gets cold. We have had the same water pump and the same shower head in another RV and it didn't perform in this way. Once the water temp was set it would stay the same temp throughout, even if it was turned off for a minute or so.
I don't understand why the temp keeps changing. I can turn on the shower head, block it off, and open it back up, and the water will be cold for several seconds? Why is the cold side overpressuring the hot side?
Thanks for all of the feedback,
Randy
I would guess that the location of the HW tank in relation to the shower has something to do with it. Cold may be direct from pump but hot has to flow to the tank and then back to shower. Dribble it is...
+1 On OxygenX shower head just worth it for much better pressure especially on a pump.
Your condition is normal and is affectionately called a "cold water sandwich" in the plumbing world.
The use of an Oxygenics shower head that allows for water "weeping" while you soap up will remedy this issue.
RPrince says he already has an Oxygenics shower head.
This sort of problem is likely what sandwip described, with the cold overcoming the hot at the faucet mixing valve. If the cold delivery is better (more powerful) than the hot, having the shower head drip actually makes it worse cause the cold displaces the hot as it drips. We had one coach where the heater was in the far back corner but the shower and other winks all middle or toward the front. Hot water was always last to arrive and quick to cool off.
If you can afford the water usage, leave the shower head running more than a trickle. Experiment until you figure out how much flow is needed to maintain a usable temperature.
Does the hot water system have thermal anti scald mixing valve.
Maybe you can drill the dribble port out on the Oxygen X shut off valve.
Quote:
Originally Posted by Piney2
Your condition is normal and is affectionately called a "cold water sandwich" in the plumbing world.
The use of an Oxygenics shower head that allows for water "weeping" while you soap up will remedy this issue.
|
I learned something new today!
If I use the 5 foot long shower hose at home, and or in the RV and turn the water flow off and on at the shower head, I have the same "sandwich" problem. BUT, if I turn the water flow off and on at the faucets, then I don't have that problem. Go figure.
Quote:
Originally Posted by Bigd9
I learned something new today!
If I use the 5 foot long shower hose at home, and or in the RV and turn the water flow off and on at the shower head, I have the same "sandwich" problem. BUT, if I turn the water flow off and on at the faucets, then I don't have that problem. Go figure.
|
Not really surprising - the mixing is occurring at the faucet. Closing the faucet valves stops that. The root cause is probably an imbalance between hot & cold water pressure in the feeder lines, but the actual mixing is in the faucet.
I insulated most of the hot water line between the Aqua Hot and the shower. Most of the cooling off of the hot water during a short pause to soap up has been eliminated.
If it's a difference in the cold and hot pressure at the shower mixing valve, a back flow valve on the hot line located right behind the mixing valve should take care of the problem.
Many newer home systems shower faucets have check valves in both hot and cold side; suspect this would cure. TOH had a show the other day showing an upgrade kit for an old single-handle shower faucet that fixed issue for them, but unfortunately, I HAVE NEVER seen any kits to EASILY fix the RV issue? CHECK VALVES AT OUTSIDE SHOWER WOULD ALSO HELP.
Are you looking for a project . I think there is a kit, but easier if you have rear to faucet access panel. Kit hasn't come up in a while I am the worst with names.
EDIT not sure if this is only one
https://showermiser.com/
I still think the dribble hole in shut off button for Oxegenex may be enlarged to help. My guess there's a spool to a chamber opens to dribble hole.
Don't think that I have access to insulate the hot water line, but I'll check the dribble hole to see if it can be enlarged. I have installed a shower miser in a previous rv for water conservation, but I didn't have this hot to cold issue with it.
I'm not familiar with check valves for water supply lines but I'll also look into that.
This problem is really frustrating!
Thanks for all of these suggestions.
Randy
Still fighting the problem...and getting really aggravated.
Installed a check valve on the hot water inlet to the shower faucet. The water goes from hot to cold with the faucet fully open, and still cool when shower head is closed. Don't know what could be causing this??
Randy
If you have outside shower, did you verify not still winterized position on valves? Verified HWT Bypass closed?
Are you also saying ONE check at shower (did/did not) change problem?
The TOH faucets did have built-in checks on BOTH hot/cold. Large, multi-story buildings w/ central HW systems use HW LOOP to keep hot available, but one janitor sink without check valves and faucets left open (off at bucket fill hose tip) can cool the entire building HW supply.
<<Why is the cold side over pressuring the hot side?>>
Guessing a FEW factors involved: 1) Season= winter water is COLDER (40-60?) than summer (60-80) water, so takes LESS Cold flow to have bigger impact on temperature; 2) Tank= 130-140, but HW Piping and tank has more elbows/ fittings/ restrictions, so HW FLOW restricted MUCH more. 3) DELTA-T... = much closer to shower= Cold than (shower = too hot) where 98=cool/cold for shower, 104-115=desired, so cold= 40-60 COLDER than desired, but hot only (usuallY 10-30 hotter than desired due to BURN RISK.)?
If at home washing the the dogs in the tub, or dry camping and conserving water. It's normal for us if we stop the water with the valve in the handheld sprayer. As other mentioned I think it the inbalance in water presure at the mixing valve that has been left open and cold water backing up into the hot water line.
I say normal also just leave it on and shower faster if needed. I prefer camping that has a sewer hook up and take my time.
Yes, I did install a check valve on the hot water side of the shower faucet, and it didn't make any difference.
After reading comments about the hot side having more pressure resistance I decided to try something in an attempt to even the two sides out. I installed a ball valve on the cold side of the faucet, and closed it about half way. This has improved the temp fluctuation to an acceptable level, at least to my hand under the faucet. Will be giving it a real test on the next camping trip.
Thanks for all of the input!
Randy
Well HERE is a possibility I had not seen before for RV?
https://www.amazon.com/2-Handle-Ther...xpY2s9dHJ1ZQ==
That looks like just what I need, thanks!
Randy
I purchased one of the faucets that you linked on your response and installed it today. It cured the issues that I was having without using a check valve or throttle valve. Thank you Thenne1713 for your help!
Randy
Another possibility is someone left the outside shower valves open and shut off the head with the button. This allows cold/hot water to move from one to the other.