Water Heater temp setting

[ricksoth]

I have an ancient square box type water heater (Seward, Atwood, etc) on my Cal 2-27 that I have been unable to find a manufacturer labels on so far and access is a bitch. This has to be a small unit 3-6 gals given the small size of the square sided box.

The engine heat-exchanger is not used as the inboard is gone, but the 120v system heats water rapidly. I'm worried about the temps I'm seeing at the faucet.

Start the heater: 60 deg
30 minutes: 122
60 minutes: 159
75 minutes: 152
90 minutes: 149
120 minutes: 150

Seems like I have a working thermostat at 150, which is way to hot. This is at galley sink which is ~3 feet from the heater in the cockpit. Checked using a bbq digital thermometer in a cup of hot water after the faucet ran for 15 seconds or so.

The boat has copper 3/8" tubing for the water system and after a month or so, I get some brownish "rust" looking water for 15 seconds or so, but then it clears up.

Is 150 temp what others see. Can this be lowered?

Reading other posts here I'm somewhat afraid to "touch" it since it does not leak and is working, but I want to be safe if we use it.

Thoughts?

pper piping and fittings, and a rusty T+P valve that does move when pulling the sprig handle.

 

[jssailem]

I have not checked the water temp, but it is plenty hot. I mix it with the cold tap to provide a pleasant temp for washing dishes etc.

You can get a mixing valve and remote control your water temp for the sink.

I let the heater heat the water as designed. No clue what the electrical heating unit generates in temp, just know it is hot.

 

[DeniseO30]

I think most of these small water heaters have a fixed temperature element probably not that accurate and probably around 150. It may be different on the water heaters that do not have the engine heat exchanger installed because then the element would be the primary heating source maybe those type water heaters would have an adjustable thermostat on the or near the elements.
If it's old you're probably going to be replacing it anyhow because it probably has sediment in the bottom.

It gets even hotter when the engine heats through the heat exchanger of the hot water tank,
what happened to the engine???

Mixing valve is the way to go but again if it's old, replace it

 

[Hayden Watson]

Have you looked under the electrical connection panel to see if it has an adjustable thermostat? whether or not the t-stat is adjustable, many boaters like the water to be "over-hot" so that by mixing it with cold, they will have more gallons of properly heated water available. The safest way to do this is with a thermostatically controlled mixing valve that automatically add the cold water.

 

[dlochner]

The temp setting is usually on or near the heating element. Remove the cover and take a look.

Heating the water to 150° kills any bacteria in the tank and water. Adding a thermostatic mixing valve will let you keep the water very hot in the tank with the water at the tap at a safer level.

Somewhere on the tank is an anode that probably needs to be replaced. The brown crud is the same stuff that is at the bottom of your HW tank at home. Time to drain and flush the tank.

 

[RoyS]

As mentioned above you should install a mixing valve at the water heater outlet. I use the Honeywell AM-1 with union fittings and threaded connections. Readily available and not overly expensive; check on line for correct suffix of part number for your plumbing connections. I use threaded with hose barbs but they have other available connections from PEX to sweat copper as defined by the part number suffix. Installation is easy.

 

[ricksoth]

Thank you everyone. I will explore the mixing valve.

 

[DeniseO30]

You might explore the age of the water heater also and mixing valves do not have to be mounted right on the appliance they can be mounted nearby making it easier for the connections,. I like to use water heaters that have the heat exchanger connections at the other end,

 

[sail sfbay]

...........Is 150 temp what others see. Can this be lowered?

120 - 140 F. I set mine at 125 F. Need to check to see if you have a water heater thermostat to adjust.

 

[Allan12210]

Thank you everyone. I will explore the mixing valve.

I found my post when I added a mixing valve to my water heater.

Thermal Mixing Valve

I finally upgraded my water heater after reading the posts from Mainsail, Stu, et. al. to a safer system. As you all have no doubt discovered the hard way, the water that comes out of the tap after using the engine to heat it is really HOT. I find this out every time I leave the handle set from...

forums.sailboatowners.com

 

[DeniseO30]

For those who are less inclined to be pipe fitters and try and install a mixing valve a the simpler alternative is to use single lever faucets and yes, 4-in plumbing faucets will fit most boats unless they did something weird the connections are identical. .