WATER HEATER THERMOSTAT

[halfmoon]

Do not have owner's manual for water heater on "new" 2001 28TE. Need to turn the heat down. How do I accomplish this and how do I find an owner's manual?
Thanks

[amber jj]

You most likely don't need the manual.Just shut the power off and open the service cover on the side or wherever the wiring goes into the unit.Pull the cardboard and insulation away and the thermostat should be on the tank wall.Just turn the dial up or down as required.It will be calibrated.

[OldDemps]

Does the water heater thermosat still regulate the (FW) water temp when it is being heated by the engine loop??

My Galley / Head hot water under way is dangerously hot and I'd like to turn it down.

Thanks

[halfmoon]

Technician who helped us with recent water heater problem (pressure relief opening and consequent loss of water into the bilge,) remarked that underway with engine temp at 180 it was possible for water in heater to eventually become hot enough to cause relief valve to open. My initial question in this thread was instigated by loss of all water when on shore power. We found that under high heat, relief valve could be closed by running hot water tap, thus putting cold water into the heater and lowering pressure/heat enough to close the pop-off relief.
So, it appears that the thermostat only controls the electric heat element and its contribution to water temperature. Engine loop contribution to temperature is independent and not regulated. This opinion is influenced by recent dealings
with my boat and I will yield to superior experience and knowledge.
Alex Kehayes

[Pitou]

In my 28 I have the original 6 gallon Force 10 which is now Kuuma Products. Three seasons back I got a full education from the owner of Kuuma Products. His name was Mark, you've got to love it when the owner answers the phone.

I called to order a heating element as my 120V side was not working and I only had hot water when the engine was running. He sent me back to the boat with instructions on how to test the various components using visual inspection and a multi meter and to call him back after my inspection: 1). 120V / 1500W Heating Element; visual inspection / if it was a complete loop and not broken the heating element was fine and functioning / it was fine 2). 120V Thermostat ;(non adjustable) senses when tank hits 140 F. 3). Hi Temp Limiter; receives a signal from the thermostat when the water temp. hits 140F which shuts down the 120V passing through to the heating element.

During my testing I found only the thermostat not functioning. I then called back and shared the results of my testing and how I appreciated him sharing how to troble shoot the issue. He responded how he really enjoys a customer who wants to repair a unit and not just curse and toss the whole heater in the trash and wrestle with putting in a replacement. Believe me, replacing the hot water tank was the last thing that I wanted to do. He felt the typical 100 hour seasonal average on the engine recreatioal boater could easily expect 20 years on a hot water tank if they did the occassional parts replacement.

Here's the best part .... he packed up all 3 components free of charge and shipped them for a nominal $5.00 fee. That's customer service for you. He connected me to his secretary to process the order and when I told her how grateful I was she told me that when it's busy on the phones he often answers and if it's a parts call the customer always gets them for free with a nominal shipping charge. Through his helpfulness he had already gained a customer for life, but at the point of "free parts" he really got me! Go Kuuma / formerly Force10.

I did replace all three parts at that time and last season I replaced the heat exchanger hoses and hot water is plentiful whichever way it is generated.

[halfmoon]

If the water heater has nearly same length and width it seems that the unit should be rotated 90 degrees so work on replaceable parts could be done with two hands under direct vision. Has anyone considered doing this. I have just replaced relief valve but am reconsidering replacing thermostat, don't see how it can be done with only one hand.

[elad]

When I recently had my 6LP-STE pulled for service the mechanic convinced me to disconnect the water heater engine loop. His reasoning was that thwe heater could malfunction and drain out the water leaving the engine starved. Not sure if this is a concern but followed his advice and had it disconnected.

[Pitou]

If the water heater has nearly same length and width it seems that the unit should be rotated 90 degrees so work on replaceable parts could be done with two hands under direct vision. Has anyone considered doing this. I have just replaced relief valve but am reconsidering replacing thermostat, don't see how it can be done with only one hand.

Not sure how yours is mounted, but I had plenty of room aft to twist myself up as the business end of the heater was facing aft. Not fun, but doable.

IMAG0063 (640x480).jpg

When I recently had my 6LP-STE pulled for service the mechanic convinced me to disconnect the water heater engine loop. His reasoning was that thwe heater could malfunction and drain out the water leaving the engine starved. Not sure if this is a concern but followed his advice and had it disconnected.

I think your mechanic is overly worried. Lots of boats run a hot water tank loop & lots of boats also run a loop for a heater unit too. You could also lose your coolant through the heat exchanger, fresh water pump, manifold and various hoses. The key is that as the captain of our boats we need to pay attention, open the engine cover & inspect. Keep an eye on our gauges too. I personally like having some hot water to wash my hands when away from the dock.

[halfmoon]

If you look at the photos posted on my "2ACs in a 28 TE" you'll see that the support for the shelf for the 2nd AC unit pretty well obstructs access to the heater. Can't approach from aft, have to come through "L" hatch opening. Was able to replace the relief valve with great effort, but one hand wrench work is much easier than trying to unscrew wires, and put them back together again.

[Pitou]

Oh my, not much if any room to work. The luxury of that 2nd AC does make access difficult. I'm sure that the 2nd AC unit was an aftermarket add on by an owner. You've got 20lbs of stuff in that 5 lb. hole. Boats can be a challenge as so often happens is that to get to a problem a handful of other things must be taken apart, moved or removed to get to the project at hand. I love it when people ask why it took so long to replace that one little screw. ... it's getting to it that takes the time!

Good luck with your project.

[halfmoon]

Should it be necessary to replace thermostat or element, I think I would change to a 3 gallon heater that could be oriented in a user friendly position. Hate to think of the effort needed in removal. Spoke to the Kuuma folks, asking if connections and element could be placed on the long side. They could not do it and recommended a smaller or cylindrical tank. The only thing I could find to fit the space was the smaller heater.

[Nancy]

This is a very informative thread, and I have a follow-up question.

I understand that some water heaters have technology built-in to control the water temperature when the unit is being heated by the engine. I'm not sure that our 20YO heater has this technology. When heated by the engine, the hot water gets dangerously hot, probably because the engine temp is 180 degrees. The water temperature is fine when heated on 110V.

There's a valve that controls the flow of engine coolant to the hot water heater. It has been fully open. If we partially close it, will that reduce the temperature of the hot water? And could any components be damaged by running the engine with this valve partially open instead of fully open or fully closed?

[halfmoon]

Might it be possible to put a thermostat in line that would open and allow the heat exchanger fluid to return, bypassing the water heater but maintaining flow?

[Pitou]

I understand that some water heaters have technology built-in to control the water temperature when the unit is being heated by the engine. I'm not sure that our 20YO heater has this technology. When heated by the engine, the hot water gets dangerously hot, probably because the engine temp is 180 degrees. The water temperature is fine when heated on 110V.

That's some good info that some units have the technology to regulate the temperature when running off of the engine coolant loop as a heat exchanger. That would be nice to temper things. What manufacturer did you see that has this? I've actually never found the water temp to be an issue as I always mix cold with hot which helps to make the 6 gallons last awhile after engine shutdown without running a generator. I will admit that running the hot water on its own is scalding, but even off AC power with these little units set to shutdown at 140 degrees.

There's a valve that controls the flow of engine coolant to the hot water heater. It has been fully open. If we partially close it, will that reduce the temperature of the hot water? And could any components be damaged by running the engine with this valve partially open instead of fully open or fully closed?

Not sure if your loop has ball or butterfly valves, but I'm sure that if you closed these down equally the water would heat up more gradually and not transfer heat as quickly with the limitation of the closed valves letting less coolant pass. If your engine run time is short it may accomplish a cooler temp in the tank, but if you run for awhile the exchange of temp will eventually catch up to your engine coolant temp.

Partially closing these valves will have no adverse affect to your engine. At one time while waiting to replace a cracked hose I ran with them closed for a couple of weeks.

[Pitou]

Might it be possible to put a thermostat in line that would open and allow the heat exchanger fluid to return, bypassing the water heater but maintaining flow?

Not a bad idea if there is something out there. A simple T with a thermostat in it sounds good to me.