City water and tank water - understanding the proper use of the water heater

[NWRVERNORCAL]

I have a brand new Shadow Cruiser 28'  .  I am hooked up to city water.  My propone is on and working as I am able to light the stove.  When I run hot water the temp is luke warm at best with spots of warmer water.  Does the pump need to be on in order for the hot water heater to fill and heat water?

 

[Selah]

Do you have an outside shower? It you have the hot and cold water on but the shower head off (on the external shower) it will shunt cold water into the hot water lines, causing just warm water at the faucets.

 

[Carl L]

This a travel trailer, right?    The pump should not need to be on if you are on pressurized city water. 

 

[NWRVERNORCAL]

Thank you.  I have to check the shower but when I woke up the DSI/FLT was lit.  I have propane.  The stove lights.  What else could it be?  Is there a gas valve to the hot water heater?  I dont think so because doesnt the monitor panel switch control that?  Thanks for the help guys.  This is frustrating.

 

[Ernie n Tara]

Bypass valve in correct position?

 

[NWRVERNORCAL]

It is an in line valve and I believe the proper position is parallel to the line.  Perpendicular would normally be off. Correct? If that is the case the by-pass valve is in the paralell postion.

 

[Gary RV_Wizard]

There is no manual gas valve to the heater. The gas valve is controlled by the heater circuit board as needed.
The fault light means it attempted to light but did not succeed. Not necessarily anything more than a gust of wind, but could mean dirt or an insect nest in the burner feed tube. Just turn the heater switch off and on again and see if the problem persists. This is probably not your original problem with intermittent hot water.

Your not-so-hot problem is almost surely caused by cold water mixing with the hot somewhere downstream from the tank. Typically this means a valve is open, e.g. the shower hot & cold are partially open with the water turned off at the shower head, or the heater bypass valve is partially in bypass mode.  Your heater bypass valve appears to be in the open position (parallel to the line) but we can't tell whether it should be open or closed to be in bypass mode. A picture would help, or you could just try the other position. Another common problem with a single valve heater bypass plumbing is a failed check valve where the line exits the heater. It is not unusual for the hot water exit check valve to get stuck due to crystallized mineral salts in the hot water. Check valve replacement may be necessary. You said the trailer is new, but has the heater been in use long? Hard water can take a toll on plumbing!

Last, do all hot water faucets act the same? Try each one and see if any are OK.

 

[bucks2]

I'd do the simple things first. Light the hot water heater, let it run til it shuts off, then have someone turn on the hot water tap at the sink while I felt the hose where the water exits the heater. If it's hot, then I go further downstream (so to speak) and see where the hot stops. If it's not hot leaving the hot water heater, then I go upstream and find out why the heater isn't heating.

All the other suggestions are great possibilities, but they're scatter-shot. If you know where the hot water is or isn't you can hone in on exactly what the problem is. I really like the one with the outside shower turned on but the shower head turned off. That solution could only come from first hand experience.

Ken

 

[NWRVERNORCAL]

Thank you all.  The outdoor shower was turned on at the cold and hot faucet but the head was off.  I rectified that but the heater is now in DSI Fault mode.  I turned it off and on with a wait time of a minute between nothing.  I turned on stove burners for a minute because I thought there was air in the propane lines.  That is not the case.  The reset swicth with the outside panel is not active (meaning I can press it).  I checked fuses all ok.  Any thoughts? In the mean time I will send pictures.

 

[Gary RV_Wizard]

When you turn the heater LP mode switch from Off to On, do you hear the heater attempting to ignite (clicking sound of the sparker)? You may have to stand by it while someone else flips the switch to be sure. We need to know whether it goes through the start cycle but fails to light, or never even tries to light. It could even be that it lights but then goes out.  In normal operation, the red light comes on immediately and goes out once the controller detects that the burner has lit.

 

[NWRVERNORCAL]

Red light comes on immediately and heater does not go through start up sequence. I am thinking I should check to make sure it is full of water also?  But I think it is becuase I am getting cold water throught the hot waer vlave and the heater is not by passed.  The by pass valve is closed.

 

[Gary RV_Wizard]

If you get water from the hot faucet with the bypass in both closed and open positions, there is water in the heater tank. I stated it that way because "open" and "close" does necessarily equate to "Bypass" and "No Bypass", cause it depends on how the plumbing is designed and whether it is a single valve or a multi-valve bypass design. And a single valve system is never actually closed - instead it is a diverter that shunts water into one pipe or another.

What brand and model of water heater are we talking about here? I'm thinking its a loose/broken wire on the heater control board, or a bad controller. Or maybe no 12v power to the controller at all. Have you checked the fuse for the heater?  The red light stays on until the heater lights, so if it never tries to light...