Plumbing Question!!! Hot Water Pressure Differences.

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Well-known member
Jan 7, 2007
Modesto, CA
      I am trying to figure out why my '99 Forest River Wildwood T29 has different hot water pressure/ flow rate at different locations when hooked up to the city water supply.  I will add here that the cold water pressure/flow is great at all locations.  I tried turning on the water pump, but it did not help, and logic tells me that it should not be used in conjunction with city water supply.  I will also add here that there is nothing in the fresh water tank, at this point.
    The pressure/flow rate at the kitchen sink, which is the closest to the hot water tank, has great pressure/flow, but at the vanity and the tub/shower, the hot water is there, but the flow is hardly a trickle, well, a little more than a trickle, but not by much.  This will not fly with the lady of the TT...who has to be "clean" and needs a bath every night. 
      Do I need to have at least some water in the fresh water tank at all times in order for this to work correctly?

      I'm not necessarily new to RV'ing, but this is the first one I've owned & OPERATED!!!

Thanks for any & all help!!!
Sounds like you have a kinked hot water line between the hot water tank and the bathroom.  These are usually run inside the cupboards, so it's possible someone shoved something heavy on top of a line.
First,  you do not need anything in the fresh water tank if you are on city water. The water pump is also connected prior to the city water inlet so it does nothing for the city water. As Lou pointed out it sounds like you have a problem in the line to the bath. It is either crushed, kinked, or blocked. If this is a "new to you" rig I would take it back to the dealer and have them fix it. If not then try following the plumbing from the H2O tank to the bathroom. You most likely will find a problem in the line.
You are experiencing a water flow rate problem rather than a water pressure problem.  An inadequate amount of water is flowing through the hot line to the other faucets, ergo the diagnosis of a kink or similar problem in a water line.  Could be some sort of blockage too - it is not unknown for a piece of construction debris to be found in a water line.

Unfortunately, it is also fairly common to suffer this problem simply due to inadequate design in the plumbing, i.e. water lines that are too small or have too many joints/angles to allow adequate flow to the faucets that are furthest away from the tank. A lengthy 3/8" hose with multiple tees or elbows can cause a significant drop in flow rate.  Trace the water lines from the tank outlet to the slow faucets as best you can and see what the plumbing looks like. You may see a kink you can fix or a length of line that can be reduced in length or complexity.

If you put water in the tank and turn on the pump, it can be used in conjunction with city water if desired.  We have done so when the city water pressure is low, i.e. below about 40 psi.  Your water pump will come on only if the pressure in the line drops below about 40-45 psi and will augment the city water pressure and flow in that case. Sometimes helps give a better shower.  You will have to refill the water tank from time to time when using it this way, because part of the water flowing through the system will come from the pump/tank.  Do not leave the pump on if the tank is empty. The pump will still run if the pressure in the line drops below its threshold (about 40 psi) but with no water in the tank it just runs and runs and gets hot.  Those pumps will run dry for awhile without damage, but it puts a lot of unnecessary stress on it.
I took the vanity faucet completely off, attached it to a house sink supply, and both sides, hot & cold run strong.  There is no "screen" visible anywhere under or around or in any way connected to this faucet.  Before I bought the TT, I think it sat idle for quite some time, stored and unused.  What else could be the problem?
If you can't find a kink or other obstruction, chances are the piping may have a lot of calcium buildup. In that case, I personally would drain the h/w tank, pump a few gallon of regular vinegar into it (you can do this by attaching a hose between the jugs of vinegar and the drain outlet, opening the pressure relief valve, and raise the jugs above the tank level so gravity will force it in.), replace the drain plug and fill with regular water, then turn the heater on to get the mixture hot. Once hot, open each hot faucet until the hot vinegar solution starts to come out, then close them and let sit for about an hour or more. Drain the water tank again to remove any unused solution and calcium flakes, then refill the tank with clean water and run it through the hot faucets until thoroughly flushed. Remove any screens first, as there will probably be a lot of flakes coming out. Vinegar is a weak acid to begin with, and mixed with water shouldn't do any damage.
I think I am going to hook up the faucets to a hose and reverves flush the lines out through the water heater 1 at a time to see if that works...I will remove the anode so that everything flushes out the bottom of the tank.  I really dont think there is a kink...this trailer was so unused that there are still drill millings undernieth the sinks and in other obvious, yet cleanable places.
I doubt if there is a kink either. Odds are you've just got an under-designed water system.  Simply inadequate water line capacity for good water flow at the faucets. Pretty common in RVs until very recently and still common in entry level models.

What size are your water lines in the rig?  Probably 3/8" poly and further restricted by various fittings.
The line sizes have an OD of at least 9/16 or 5/8"...I am not willing to take any of it apart just to find out!!!  Interesting thing happened yesterday.  As I was backflushing these 2 lines, I found that the water heater tank had allot of sand and scale on the bottom.  So I took a round twisted-wire brush with plastic bristles and tried to wiggle it all throughout the inside of the tank, until nothing flowed out with the water (which was now supplied via the fresh-water system).  After taking apart the sink & shower faucets with no visible blockage, I got frustrated!!!  I then put it all back together.  I started to quickly turn on & off the hot water side of the faucets...very rapidly.  Then to my surprise, they started flowing some, & then, full-force...problem solved!  Have no idea what was the actual blockage, but now I no there are no kinks.  I may replace the faucets with something a little more reliable...Any recommendations?
The line sizes have an OD of at least 9/16 or 5/8"

Yeap, but they aren't thin wall copper tubing like your house plumbing, so the ID is something like 3/8". Your stick house will have a minimum of 1/2" ID, which flows 50+% more water than 3/8".

Since your hot water tank's outlet pipe is near the top rather than the bottom of the tank, no amount of sediment can affect it. Not sure what your tank cleaning job did, but I can't knock success either!
The problem is still there...our maiden voyage was just last weekend and I had to take a trickle shower.  The water just would nor flow...there is something wrong with the faucet and I'm not willing to go through the frustration of trying to fix it

I need a recomendation of a brand of tub/shower faucet that is reliable!!!
Some shower heads have a restrictor of some type.  Ours has a small o-ring in the handle of the shower head where the hose connects to the shower head handle.  This can sometimes become partially blocked. Try checking the hose for a restrictor and clean it out.
The problem is in the valve within the faucet previously mentioned, you can turn the hot water side on and off rapidly about 50 times before any flow starts...then progressivly get better.  Problem is you waste alot of prcious hot water in the process.

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