How do I fix fluctuating water temp in shower?

[knockabout]

fluctuating shower temperature when sea water brakes into the cockpit while using the 12vlt shower out of the plastic bucket / heated to perfect temperature with water from the kettle / medical professionals assure us hot- cold bathing techniques are good for our health / you blokes are spoilt

[Pelagic]

Originally Posted by svthreecheers

Whats a Navy Shower ??
Cheers
Siggi

Wet down /shut off water/ soap up and scrub/ rinse off.

Of course, these days with no more discrimination of the Sexes or sexual preferences in the military, a Navy Shower could mean something completely different....

[svthreecheers]

Thanks Pelagic
I think I go for the second option
Cheers
Siggi

[greensail]

Hi.

I had the exact same problem. It was air in the top of the hot water heater creating the pressure that over rode the cold water pressure when the water pump stopped while cycling.

Try bleeding the air from the top of the HW tank by opening the pressure relief valve manually if you can. That solved my problem.

All the best
Bob

[malbert73]

Great feedback. Since I have check valves in all places described I think I will first add a thermostatic mixing valve off of water heater. I'm tempted to adjust it to perfect shower temp around 105 deg so no mixing is needed at shower handles unless you want it cooler. That will minimize water waste. Since we don't have dishwasher don't need hotter water coming out of tap. Will be safer for our kids.
I'll also bleed air out of water heater.

Stand by- I'll report back in a week


Sent from my iPhone using Cruisers Sailing Forum

[doublewide]

We installed Isotherm thermostatic mixing valves on our water heaters as a safety measure to avoid scalding. The engines can heat the water dangerously hot. These valves eliminated the problem of too-hot showers.

I think all new water heaters come with these valves. We had to retrofit ours as they were several years old. The mixing devices are not expensive, and the installation is simple and straightforward. If you don't have them, you should add them for safety.

[Stu Jackson]

Originally Posted by doublewide

I think all new water heaters come with these valves. We had to retrofit ours as they were several years old. The mixing devices are not expensive, and the installation is simple and straightforward. If you don't have them, you should add them for safety.

No, they all don't, only Isot...

You're right they should, but heck, it's a boat so DIY. A Google search on thermostatic mixing vales will show them all, Johnson makes one, as does Honeywell. Not hard to find at all.

Good idea.

[DuncanC]

Hi,

I had exactly this issue on my yacht, although I did change my hot water tank arrangement in the process of fixing it.

Previously I had a pressurised hot water tank which was supplied with pressure from the cold water inlet. the water pressure came from my Jabsco pressure pump. Due to distances up and down the length of the boat (and the various routes required to get from pump to tank to taps etc) this meant that the cold water travelled maybe 5m-fore from the pressure pump to the shower taps; but the hot water tank was perhaps 5m-aft of the pump. So overall, to get pressure to the hot tap in the shower the pump had to go along around 15m of pipe. This meant that the temp was always yoyo-ing.

Then to get a bigger tank I changed my setup, still with the standard Jabsco pressure pump which supplied pressure to the cold taps but now the much bigger hot water tank (which is a vented tank) has a header just above. Then on the hot water outtake of the hot water tank I fitted a mixer valve set to get the water at a good temp for showers and washing up. I then fitted another jabsco pressure pump to take the warm water from the mixer valve adn pressurise it into the hot water pipes.

The result is that the new pump alone pushes a ready supply of water upto the shower, with great results :-)

The Jabsco support ppl advised that the pumps can handle upto 55 Deg C happily. As I have set the mixer way below this, I don't expect the 'warm' pump to have any issues. around 8 months so far without a problem.