Hot/ Cold Shower, no Hot Water

[ranger098]

My Hot/Cold shower has next to no hot water. My problem is that if i only open the hot water side and leave the cold side closed, i only get dribbling water, no pressure at all. Open the cold side and i get good water pressure but it's only cold. what gives?

I confirmed that the hot water line is clear and open, and running the engine with the hot water hose disconnected results in hot water shooting from the engine as it should.

My theory is that gravity is doing its job and not letting much hot water through. The pump turns on and grabs cold water, but as i understand it does not grab hot water, that is to be fed by the pressure from the engine. Right?

[996scott]

not sure but isn't there some kind of filter/strainer where the hot and cold water lines connect into the manifold? Might be worth checking there. Sorry not much help

[gregski]

I've normally seen the pump on the "mixed" side, so that it pulls both hot and cold. Gravity certainly won't work if the shower head is higher than the engine. The engine water pump produces a little pressure, but I don't think it's near enough for the shower.

[parrothd]

Call heater craft.. ;)

[moombahighrider]

My pump is on the mixed water side. The pressure of the hot water in the block is not sufficient. Sounds like you need to re-plumb it...

[ranger098]

Call heater craft.. ;)

Ya thats a good call... surprised that not more people have had this issue. Might just be the location of the mixer/control knobs being too high so not enough hot water makes it to the mixer. Ill try putting that lower in the boat to see what that does.

[gregski]

Might just be the location of the mixer/control knobs being too high so not enough hot water makes it to the mixer. Ill try putting that lower in the boat to see what that does.
The height of the mixer/control valves won't change anything, it's only about the water outlet (the shower head). If you hold the shower head below the height of the engine, you'll probably get some hot water. I really think you need the pump on the mixed side, I just can't imagine that there is enough water pressure from the engine's water pump to supply a shower.

[ranger098]

The height of the mixer/control valves won't change anything, it's only about the water outlet (the shower head). If you hold the shower head below the height of the engine, you'll probably get some hot water. I really think you need the pump on the mixed side, I just can't imagine that there is enough water pressure from the engine's water pump to supply a shower.

The pump is on the mixed side, i was originally thinking the pump was only on the cold side but after looking closer it is on the mixed side. I tried to trace the water pressure from the hot side but the water was burning my hands while troubleshooting! Gonna try and see how much pressure i have at the mixer (aka valve). I checked for obstructions once in the mixer and didnt find any, but ill check that again. These systems are pretty simple so you'd think it would be easy to find and issue if there was one.

[Amanda_Pulliam]

Close off water. Remove the cartridge. Also, clean the little particles blocking high temp water. Reassemble.

What is likely occurring here is that the plastic plunge tube in the heated water tank is beginning to deteriotate. Plastic bits are flying around the framework, blocking sections. Happened to us and is a major problem.

[996scott]

This thread is almost 5 yrs old, hope this has already been resolved :)

[Amanda_Pulliam]

Here are some links which might also help.

https://www.youtube.com/watch?v=GP-78EqAalM
https://tanklesswaterheaterexpress.com/no-hot-water-in-shower/
https://www.bobvila.com/articles/no-hot-water/