[Stephen]

This is all very interesting and mostly as to the RO system. All worked perfectly until I changed filters (?). The ice maker works but the coffee system nor the drink fountain is inop. So, as to Dicks questions I wil check the valve on the hot water heater but we have hot water.

I will need to investigate this RO system thoroughly, it may be the culprit.

Thanks everyone

[Art]

Dick, explain how a leaky TP valve on the HW tank puts water in the holding tank?

Also, just to clear up confusion the only time that valve opens is when the water in the tank expands due to heating, and once the tank contents are at temp the expansion stops and the valve remains shut.

If the wrong valve was used (a 175 instead of the 75) it usually never opens, but the excess internal pressure expands the tank end caps.

[Archived]

Jon asked, “Dick, explain how a leaky TP valve on the HW tank puts water in the holding tank?”

Its a stretch. First someone decided that the water heater overflow should be plumbed into the holding tank rather than be allowed to discharge under the coach (as Liberty plumbed our coach). Then the Temp/Pressure release valve would have to go bad allowing water to escape when the hot engine coolant is used to heat the water in the water heater. With the water pump ON while driving the coach there is enough pressure now (between the water pump and the expanding hot water) to force water out the TP release valve and into the holding tank (rather than under the coach like Liberty had intended it to). If you drive long enough … much of the water in the fresh tank ends up in the holding tank.

I realize that some stars have to align for this to happen, but in theory this could happen.

[Archived]

The discharge from a TP valve dumps to the ground.

[David]

Jon … I’m well aware that the TP relief valve dumps to the ground under the coach.

There is a very, very remote possibility that someone at somepoint plumbed the TP relief valve discharge to the holding tank. Very remote, but a plausible circumstance.

[Archived]

There is a remote possibility I might eat razor blades for breakfast, but sending Chuck on a wild goose chase without advising him the chance you suggest is as likely as peace in the middle east is unfair to Chuck and others who read these responses.

[Archived]

Point taken. I’ve edited the my reference to include “while highly unlikely”.

[Jeff]

While you note I am critical of wild goose chases in one respect your comments are on target Dick.

Chad just dealt with creative problem solving by a previous owner and those kinds of “repairs” or “updates” are so off the wall people that tend to rely on logic for problem solving are blindsided.

We just have to qualify our responses, while recognizing strange things do happen.

A long time ago a member called and wanted some help to understand why his level low system wouldn’t make the bus go up (or down, can’t remember which). We discussed the system, how it works, what fails, how to diagnose issues, etc. and not a single thing determined the problem. He finally called when he found the problem. Turns out his pneumatic system had never been serviced and a Norgren valve was full of water and would not shift to open or close the valve as required. Big lesson for me to always be prepared to think outside the box, but to qualify that thinking so nobody starts chasing obscure solutions.

[glen]

Not to create thread creep here but Dick you hit a point that no one ever thinks about, how hot the engine loop when on will get the hot water.

I don’t know if any converter ever installed thermostats on the hot water loop to keep the engine water from over heating the hot water in the hot water tanks.

As we know, engine water will be from 180ish to 200+ at times while driving.

That coupled with most all heaters pressure relief valves are house hold type that are set at 175 degrees, not a good thing.

Why would anyone plumb the relief valve from the outside to the holding tank !

[Archived]

Buddy,

I am unaware of any coolant heated water tank having the coolant heating thermostatically controlled. We had all 3 coaches with unregulated HW heating via coolant, and just thought it was a neat feature until our grandson travelled with us, and then we realized the danger he was in if he got his hands into that hot water.

There is a myth that the temperature can be regulated by closing the coolant valves to the HW tank. The only time that could possibly be true is if the coolant flow is regulated to such a degree that when the temperature of the contents of the HW tank reach the desired temperature is if the coolant flowing is precisely the correct flow rate to match the heat loss of the tank water contents through the insulated walls of the tank. Good luck with that.

To correct the problem I added a second thermostat located adjacent to the factory installed thermostat (same temperature setting of 125) and used that thermostat to control a solenoid valve in the coolant line, shutting off coolant flow when the temperature is reached.

Sorry about thread creep.