Hot water flow problem

[travelingsages]

I have a problem that just started today on my 2007 Itasca Suncruiser 38J. When I turn on the kitchen faucet to full force and all hot water, the water flow starts out good and then slows down to a trickle. This is not just the usual pressure surge when you normally turn on the water. It actually slows down to a trickle. I thought it might be a blockage in the faucet until I tried the same thing in the bathroom. It does the same thing! Then to make it interesting, it only does this part of the time. The rest of the time both faucets work as they should. Has anyone had any experience with this? What can the problem be? By the way, I am hooked up to the park's water supply. I always use a whole house filter, which I changed over the weekend, and this has only happened on the hot water side, not the cold water side.

[John Canfield]

Doug - what happens when you are using tank water with your water pump?

[Jeff]

Doug:

Here is an article in our library to check.

[BigLarry]

Thanks Jeff!  Our kitchen faucet was running really slow and I hadn't taken the time to fix it.  I read the article, took Gary's advice and removed and cleaned the screen and it was fixed!!!!  Another reason to use the fourm.    Now I've got to check on how to replace the awning that was torn off in the 50 mph New Mexico wind today.

[RV Roamer]

That's areal mystery, Doug. My best guess is that the inlet or the outlet of the water heater is crimped or clogged somehow. Pressure builds up in the tank & outlet lines over time, but when you open the faucet, pressure drops because more water from the tank or city supply is not quickly pushing in behind it. Since the problem is in both kitchen and bath, I'd look at the water tank  first and make sure the tank is refilling properly. That's fairly easy to check. If it is, then check the bypass valves to make sure they are in the proper positions. In some types of water heater bypass configurations, there is a valve on the outlet side and it might be partially closed.

If it's neither of those things, look for a crimp in the hot water line from the tank.

[afchap]

I agree that you need to look at the water heater connections. There is a check valve on the WH connections that sometimes fails or even comes apart inside. It might be that it is restricting flow somehow.  Many owners have simply knocked the insides out of the check valve (some are plastic, some are metal) and continued on without it and noticed no ill effects from not having it there.

[travelingsages]

I have had some health issues lately but finally got under the rig and checked things out. I had a brass fitting with a plastic anti backflow valve in it. The valve had an "O" ring that was stretched and not allowing the valve portion to move properly. I removed the valve and put the fitting back in place and now have a good hot water flow again. As far as I can tell so far, removing the valve has not had any other untoward consequences. Thanks for everyone's input. You guys are the best!

[weewun]

If the Check Valve is on the Output side of the Water Heater (normal position) you are going to have a problem when you "winterize" as the water will backflow in the "bypass" position and fill the Water Heater.

[tennsmith]

If the Check Valve is on the Output side of the Water Heater (normal position) you are going to have a problem when you "winterize" as the water will backflow in the "bypass" position and fill the Water Heater.

I'd like to follow up on this discussion because my valve is out/open/accessible and I'm trying to figure out how to get into it and what it does.  Weewun, you say "if" the valve is on the output side....does that mean hot water out side?  If so, does an automatic winterizing system pump anti-freeze backward thru the water heater?  I thought that was achieved by opening hot water faucets and then draining the water heater.  Seems like the valve should be on the cold water inlet side and that the winterizing system should purge/flush the cold water lines...but then that begs the question....how does this valve know the difference between pure water and anti-freeze?  All I can figure is that perhaps it is a pressure sensitive valve which can be forced open by the city water/onboard pump pressure which would be on the order of 50 psi, but perhaps not by the antifreeze pump which needs to only circulate a low volume of anti-freeze.  Experts, please chime in...I'd like to get to the bottom of this.  What does this valve do?  Which side of the water heater is it on?  Can it be serviced?  Can it be removed?  How does it work?

[weewun]

Depends on your ByPass configuration. 

If you have the 3-valve system (a valve on the cold-water input #1, a valve on the hot-water output #2 and a valve between the cold-water input and the hot-water output #3 before the two valves mentioned earlier) or it equivalent then the one-way (check) valve will have no effect.  The bypass valves isolate the one-way valve. 

When you winterize you close valves #1 and #2 and open valve #3, this will divert the cold water to the hot waterlines.  No antifreeze gets to the water-heater and you drain the water-heater by removing the plug in the bottom of the water-heater (on some models that plug is also an anode). 

Many RV's  have a 2-valve ByPass configuration.  One valve turns-off the cold-water input to the water-heater and the second valve connects the cold-water input to the hot-water out line from the water-heater.  These configurations rely on the check-valve on the water-heater output line to prevent backflow into the water-heater.

You are right that the Check valve should be on the input side to prevent back flow of hot-water into the cod-water lines and that is the way that home water-heaters are built.  Unfortunately, many RV's have the check valve on the hot-water side to save one valve for winterization, all a matter of $'s.

[John From Detroit]

It also depends on your winterizing method

Are you going to spend many dollars on PINK STUFF to fill the line (ok, Ok, so I got it for a buck a gallon) or are you going to do as I do and blow the water out of the lines with a few cents worth of electricity powering an air compressor?

If you use the latter method... The lack of a check valve in the water heater outlet won't be a problem at all.

[tennsmith]

Thanks weewun and John, I am about to get to the bottom of how all of these check valves work, their purpose,  and how the winterizing system works and such.  On my 5th wheel, which had manual bypass valves and no winterizing system, it was an easy decision:  enable the bypass system, ....drain the WH, blow out the lines and pour a cup or so of anti-freeze in all the drains.  I always worried that the water pump might have residual water in it and might be damaged.  The city water port that I used to fill blow out the system bypassed the water pump, best I could determine.

Given that the motorhome has a system for doing this, I think I'm gonna try and get that system where I can use the bypass and winterizing automatic valves.  I now understand the placement, direction, and reason for all the check valves and the function/flows of the bypass solenoid and the winterizing solenoid.  Simple, were it not for failing check valves and access to them that is a laborious process.  I am replacing the stock check valves which had nylon poppets and an O ring which refuses to stay in place with the Camco all-brass units.  Not sure how reliable they are, but we'll see.   After trying it once or twice, I may revert to the fail safe manual way for the long haul and forget the check valves.

There is still enough manual winterizing to be done, draining icemaker lines, removing water filter cartridge, draining the water heater, etc.   

[John From Detroit]

Well. when it comes to problems the 3-valve bypass system is, I believe, the most trouble free.. There is basically nothing (other than a failed quarter turn valve) to go wrong.

However since they don't know what kind of bypass system the house builder will use, the water heater companies tend to ship with check valves I suspect.

And due to the nature of hot water.. The hot water check valve is the most likely one to fail.

[jbostic]

I have a 2001 Winnebago Adventurer and was not getting any hot water. It ended up being the check value mention in several replies. Thought it was my thermostat or what ever you call the regulator of heat but ended up that someone had replaced check valve with plastic valve and this did not hold up. Now have brass replacement and hope it lasts for a long time. This check valve was new to me and of course I tried turning all visible cut offs in every position. When in correct position I did not have any water flow from hot water faucets.

All is working great now-electric, gas, and motor heat systems all provide me with lots of hot water!!!

Valve is on the back of my hot water tank and is not that hard to get to once you know it exists!!??

[tennsmith]

Valve is on the back of my hot water tank and is not that hard to get to once you know it exists!!??

My cold water inlet one is on the back of the water heater also, but you have to pull the darned thing to access it.  I too have replaced the original check valve which had nylon innards and a rubber O ring which dislodges from its seat and renders the valve useless with an all brass one made by Camco.  Haven't located the second one yet....could be that it has been removed, could be that it is screwed into the automatic bypass system.  Got more detective work to do to find it/replace it.

[John Canfield]

We have two check valves on the rear of our water heater.

[tennsmith]

We have two check valves on the rear of our water heater.

Yeah John, I think I should have 2 also.  However, it may be that the one on the hot side is attached at the bypass valve mechanism.  To access that, I've got to remove a panel in the water control area to see if it is there.  If not, I'll add a second one.