Hot Water tank

[Boomer2it]

I haven't used my hot water tank since purchasing the boat August 2020, nor have I done any research on how to operate. I assume I drained it end of last season when I winterized the water system by draining all water, but now I'm not sure if I correctly drained hot water tank by just turning sink tap to "hot" side and draining until sputter.
On the flip side I am not sure how to fill the hot water tank in the spring? When filling main water tank does it flow into hot water tank as it fills up?
Hot water tank is behind engine.
Sorry for the newby question.....
Gene

 

[kappykaplan]

When you turn on your water pump and open hot water faucet, the tank should fill.

 

[Boomer2it]

When you turn on your water pump and open hot water faucet, the tank should fill.

sounds like like a perpetual filling and emptying??

 

[Scott T-Bird]

I'm not sure if I correctly drained hot water tank by just turning sink tap to "hot" side and draining until sputter.

No, it's probably not completely drained. There may be a valve at the fittings at the low end of the tank that you can open and let all the water out. Open the hot water at the faucet as you are draining. I connected a hose on my tank to drain into the bilge and avoid water running into places I didn't want it.

If you are unsure of not draining the tank, you can add antifreeze for protection as many people do. I always disconnect hoses from all the fittings and blow air through the tank to make sure it is drained completely. I don't worry about any incidental water that may collect in small puddles. I have all valves open when I leave it.

Unless you have a shut off valve somewhere on the feed line into the tank, your tank fills when you turn the pump on. If you don't open a hot water faucet, you may trap air in the tank, but it will still be substantially filled.

 

[JamesG161]

Two ways you make Hot Water.
1) Switch Breaker in your Electric Panel
2) Your engine when running,

Be sure you fill your Hot Water Tank before using either method.
Jim...

 

[DeniseO30]

These water heaters and boats rather their copper stainless or aluminum tanks tend to get very quickly filled with a couple pounds or more of sediment,
A simple RV water heater bypass kit will eliminate a lot of aggravation when it comes to winterizing.

Flushing the water heater in theory can extend the life of the tank but as we know, home water heaters aren't maintained very much very often either. )Out of sight out of mind) until one day we don't have hot water or we have a leak.

 

[BarryL]

Hey,

The water heater / water tank (same thing on a boat) is plumbed 'in line' with the water system. The plumbing goes like this:
Boat Water tank to water pump. From water pump the hose will have a T so one line goes to the cold water and the other line goes to the water heater. At the sink there will be a tap with cold water line and hot water line.

When you turn the water pump on the water heater tank will get filled. When you open the hot water tap water will be sucked from the boat water tank to the water pump., then pumped through the water heater tank and to the hot water tap.

You CANT empty the water heater tank by just turning on the water pump and opening the hot water tap and waiting for it to sputter. The water pump is not able to pump air, only water. Once the boat water tank is empty there is nothing to push the water out of the water heater tank. THe water heater will remain mostly full of water.

The only way to drain the water heater tank is to open a drain valve and let the water run out OR by removing the water input line (at the bottom of the tank) and letting the water drain out.

IMO - DO NOT FILL THE WATER HEATER WITH ANTIFREEZE. First you will need a lot of antifreeze (5-10 gallons depending on the tank) and secondly and more important, it will be very difficult to get the antifreeze out of the tank when you recommission the water system. The better way of winterizing the water heater is to remove the heater input and output hoses and connect them together. Now you have bypassed the water heater. If you never plan on using hot water, or if the heater doesn't work, you can just leave the lines like that forever.

Good luck,
Barry

 

[Hayden Watson]

Two ways you make Hot Water.
1) Switch Breaker in your Electric Panel
2) Your engine when running,

Be sure you fill your Hot Water Tank before using either method.
Jim...

1) Tank must be full anytime you Switch Breaker in your Electric Panel
2) Tank does not need to be full when your engine is running.

It is ok to use the engine when the hot water heater tank is empty because the coolant is limited to the engine's running temperature of about 180º max which will not harm the heat exchanger coil in the water heater. The problem is with the electric heating element in the tank which must be covered completely with water anytime it is turned on. The water limits the heat of the element to the water temperature and without it, the element will heat up to white-hot and burn out.

 

[DeniseO30]

Something to think about how old is the boat and is it probably the original water heater and if you haven't used it since 2020...
Consider replacing it. Probably the same maybe even less work than recommissioning & commissioning the one you have only way to find out it's got three or four pounds of sediment in the bottom like the one in my boat (done very recently) it's one of the few things on the boat that doesn't, cost over $1,000

 

[JamesG161]

2) Tank does not need to be full when your engine is running.

ok true, but NO Hot Water...

Jim...

PS: No such thing as a HOT WATER HEATER... Why would you heat Hot Water?

 

[Scott T-Bird]

You CANT empty the water heater tank by just turning on the water pump and opening the hot water tap and waiting for it to sputter. The water pump is not able to pump air, only water. Once the boat water tank is empty there is nothing to push the water out of the water heater tank. THe water heater will remain mostly full of water.

The only way to drain the water heater tank is to open a drain valve and let the water run out OR by removing the water input line (at the bottom of the tank) and letting the water drain out.

Yep, good explanation ... I'm always surprised how much water drains from the heater after I open the faucet and think "I've used up all the hot water"!

 

[Tally Ho]

Two ways you make Hot Water.
1) Switch Breaker in your Electric Panel
2) Your engine when running,

Be sure you fill your Hot Water Tank before using either method.
Jim...

I never thought about this… I certainly don’t turn on my breaker until the tank is filled…but I motor without the tank full…

I dont think that is an issue. Just don’t turn on the electric element, which will burn out without water in the tank.

Greg

 

[TimFromLI]

I'd be concerned about your whole fresh water system. If you simply opened the faucets to "winterize" the system, then you left water in the lines. I see you are from Nyack where winter temperatures get well below freezing. You need to run antifreeze through your water system, preferably bypassing the hot water tank. How did you winterize your engine? A/C sytems, toilets, manual water pumps all need to be winterized.

 

[dLj]

I haven't used my hot water tank since purchasing the boat August 2020, nor have I done any research on how to operate. I assume I drained it end of last season when I winterized the water system by draining all water, but now I'm not sure if I correctly drained hot water tank by just turning sink tap to "hot" side and draining until sputter.
On the flip side I am not sure how to fill the hot water tank in the spring? When filling main water tank does it flow into hot water tank as it fills up?
Hot water tank is behind engine.
Sorry for the newby question.....
Gene

I'll preface this with I've not had a boat with a hot water tank in it while living up north. I am going to have to deal with a hot water tank this winter, possibly, but luckily I'm now down on the Chesapeake and it is not such a big deal.

But I have a RV with hot water tank that needs winterizing. In the RV's, there is a bypass on the lines to the hot water tank. So the line going in has a valve and a Tee that has a line going to the output side, also valved, and that line running between these two has a valve in it. To winterize, you close off the valves to the tank, open the valve between the two lines and then drain the hot water tank, I usually do that by pulling the anode out of the tank and opening the vent valve on that tank. I then leave that hot water tank empty over the winter. I do not think running your pump and draining through the sink would really drain your hot water tank, only lower the level in it. I would not be confident that would be sufficient for a Northern winter... To fill the tank in the spring, you just close the bypass valve, open intake and output valves and the tank fills - pushing a lot of air out of the faucets...

I would think that boat hot water tanks would be similar in their plumbing, but I don't know.

dj

 

[Tally Ho]

Some boats have a bypass for the water heater, many do not.

My first boat (1996 Hunter 280) did not. I would pull the hot and cold water lines off the tank, and couple them together with a pipe nipple.

My current boat (1988 O’Day 322 ) has 3 valves that a PO installed to bypass the tank.

Both ways effectively allow you to NOT fill your water heater with antifreeze.

Here is my process for winterizing my boat:

1) water heater / engine circuit…engine anti-freeze circulated through engine and the hoses take the hot AF to the heat exchanger in the water-heater…this gives you hot water when motoring…no “winterizing“ of this circuit is required.

2) Engine raw water system…lake water pumped through the engine Heat Exchanger, and then out through the engine exhaust. This circuit needs to be winterized…pink AF sucked in the raw water intake, engine on, and run several gallons through the engine. Pink AF will flow out of the engine exhaust. Some people drain their water-lift muffler. I do not.

3) potable water system. Usually you have a water tank, water heater, water pump, faucets, all tied together for hot and cold water. This circuit needs to be winterized as well.

I generally drain my water tanks (run the faucets until tank empty), drain my water heater (open drain cock and direct drain hose out of a scupper drain thru hull) and let water tank drain. Opening the T&P valve helps put air in the tank. I have used an air compressor shoved into the end of the T&P valve to push the water out. Then bypass the water heater. I remove the water outlet hose from water tank, put the end of the hose in a gallon of pink AF, and turn on water pump and open each faucet (Hot and cold). I have 2 water tanks, so I repeat the process on the 2nd tank.

4) Head/toilet - also needs to be drained and winterized…I pour pink AF into the water intake strainer, while someone This pumps AF all through the toilet, hoses, valves, toilet rim, and pushed it to the holding tank. It can stay in the holding tank all winter.

Don’t just dump AF into the toilet bowl and pump it dry…it won’t get all of the valves and cavities in the toilet.

5) Finally, I usually dump some pink AF into my bilge…if I get any water in there, I don’t want it freezing solid and cracking something….so a bit of AF should keep things slushy at worst if I get water in the bilge.


It seems like a lot, but once you don’t it a few times (and make a checklist to follow), it gets pretty easy.

Greg

 

[Justin_NSA]

Good stuff posted already.
I installed a bypass circuit so when i winterize my freshwater system, i don't pump antifreeze into the hot water tank. I open the pressure relief valve to provide air while I open the drain valve on the tank.

You may also want to put 'flush and fill' your heat exchanger on your maintenance list. Mine was really gunked up after who knows how many years ago it was done by any previous owner.

 

[Boomer2it]

I'd be concerned about your whole fresh water system. If you simply opened the faucets to "winterize" the system, then you left water in the lines. I see you are from Nyack where winter temperatures get well below freezing. You need to run antifreeze through your water system, preferably bypassing the hot water tank. How did you winterize your engine? A/C sytems, toilets, manual water pumps all need to be winterized.

I run antifreeze through all the water lines and bilge pump and engine

 

[TimFromLI]

Then, if you opened a hot water faucet, you would have pumped antifreeze through your hot water tank too. it's just that you could have bypassed it saving gallons of antifreeze. Your pump needed to fill your hot water tank before anything came out the faucet. that's why people bypass it after emptying it.

 

[dLj]

Then, if you opened a hot water faucet, you would have pumped antifreeze through your hot water tank too. it's just that you could have bypassed it saving gallons of antifreeze. Your pump needed to fill your hot water tank before anything came out the faucet. that's why people bypass it after emptying it.

If you drain your hot water tank but don't take it out of the circuit, then as you point out, you use a lot of extra antifreeze. If you don't drain it, and just pump antifreeze through your system, you will never know if you've gotten enough antifreeze in your hot water tank mixed with the remaining water. I actually had something similar happen this past winter in my RV. I have a water filter that I used to not drain, just allowed it to be part of the water system as I was adding antifreeze to the rest of the fresh water system. Well this past winter, apparently the dilution in that filter was not sufficient and when I commissioned the RV this past spring, I had to replace the water filter cannister as it had broken over the winter. The only thing I can think of is that the water in it did not get sufficient antifreeze to keep from freezing. This year, I drained it and then put the antifreeze throughout the fresh water system. I guess next spring will tell the tale...

dj

 

[Ward H]

I learned something today about Anti Freeze. I've always used Star Brite -50 with PG for fresh water systems and engine systems from my local hardware/marine store. $3.98/Gal.
I always thought all Star Brite -50 was PG. Today I learned Star Brite makes a -50 called Winter Tech that is an alcohol/PG blend. Not recommended for engines.
They also sell a Premium -50 which is PG, no alcohol.
Apparently the Premium -50 is in short supply and the price has sky rocketed so the store carries both formulas. The Winter Tech with Alcohol/PG blend @ $3.98 for fresh water systems and a different brand (I forget the name) which is PG/non alcohol for engine winterizing @ $6.98/gal The store owner said that is also in short supply. He found 20 pallets and when it is gone, there is no more available. To make his supply last and to help boat owners keep costs down, he now carries both blends.