bypass hot water heater

True North

True North

Member
Sep 11, 2012
165
Live: DeWitt, MI,West Michigan (Ludington)
Boat Info
2005 SR 260DA
350 MAG MPI
Bravo 3
Engines
(1) 350 MAG MPI w/Bravo III
In terms of winterizing the water system in my boat, I completely understand the process needed to bypass the hot water heater on the side for the usable plumbing for the boat (sink faucets) to avoid putting the "pink" or air in the HWH (closed loop system).

I also understand how to drain the HWH by unscrewing the valve on the bottom.


My questions are:
1) what are the two hoses (inlet/outlet) that come from the motor to the hot water heater (black approx 1" dia). I'm assuming this takes warmed water from the motor and goes to some heat exchanger inside the HWH to warm water when not hooked up to shore power (electric power)?

2) If that is the case, how do you properly winterize that component of the system since this is a closed loop with the motor??? Will the antifreeze you run through the motor circulate through that system? What do you do if you don't run antifreeze through your motor but instead drain only? Is there a way to drain that closed loop system?

3) anybody know where I can get a schematic of what the inside of the HWH looks like? Don't need my exact model, as I'm sure many use a similar kind with varying capacities? I beleive mine is a 11 gallon, but not sure and don't have access to the boat right now.


Thanks for your assistance.
 
The black hoses are exactly as you said - water from the engine being circulated through a loop. To properly winterize an engine, water should be drained out (including draining the raw water pump and "bumping") and then AF is poured back into the engine. As such, no, you will not have winterized the HWH at this point. To do that, simply remove the two black hoses from the engine and allow them to drain (often, I'll blow into one of the hoses to help get all the water out). Then, holding one of the hoses higher than the HWH, just pour some AF into it until it runs out the other hose. Reattach the hoses to the engine and you're done.
 
when you run pink through the engine it will also run through the hot water heater lines. no need to disconnect them if you are winterizing the engine with antifreeze.
 
gerryb said:
when you run pink through the engine it will also run through the hot water heater lines. no need to disconnect them if you are winterizing the engine with antifreeze.
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That's true, but it's not the best way to winterize the engine. There's only two ways to reliably winterize the engine by actively running AF through them. The first way requires A LOT of AF and subsequent testing of the AF since it will have been mixed with water. The other, still requires draining of the standing water, but also removal of the t-stat. Without the t-stat removed, there are parts of the engine that will retain water. I have seen on many occasions, close to a quart of water being pushed out before it turns pink.
 
Thank you both for the responses. Last year was the first year I owned the boat. I did drain all the water in the blocks, pulled the thermostat and ran the "green" -100F antifreeze antifreeze through the entire system, but I did not drain the black hoses to/from the HWH. this year I plan to, but this year I was also going to blow out my water lines with compressed air vs. antifreeze through the system. It is real easy for me to drain the tank and even the pump prior to the compressed air, so I should be all set for that. I just wanted to make sure what to do with the HWH when I bypassed it to blow out the lines. thanks again.
 
As long as you're draining the block and removing the stat, you don't need to pay any attention to the raw water pump (as I noted above) nor the HWH lines. If you were using the -50 stuff, I would probably still recommend draining the HWH lines, but with the -100 stuff, you're OK. Although, truth be told, if it was me... I would still drain the lines. It only takes a few minutes. Just more of a "feel good" thing, I suppose.

You're using AF that is made up of propylene glycol, right?
 
sorry, I may have not been clear about the 2 different water systems. The water system I was draining and blowing out with comprerssed air was my water system for the faucets, not the motor. In order to bypass the HWH, I made the connection to join the water lines, but then it got me thinking about the other two hoses from the motor water system into the HWH. Based on your info above, if I drain the MOTOR water lines (blocks, HWH hoses), remove the thermostat, reassemble and run -100F antifreeze through the motor system, I should be all good with both MOTOR water systems and FAUCET water systems correct?

The antifreeze I used last year was the marine grade -100F protection from West Marine. Like you, better safe than sorry. What I did last year seemed to work, but I ran pink though my entire FAUCT water system, including the HWH and water holding tank. This year I was going to NOT run PINK through my FAUCET water system, and instead used compressed air to blow out (similar to what I do with my sprinkler system at home). Based on all of that, I should be good correct? Thanks for your help.
 
As far as the engine/HWH goes - yes, you're golden. Just MAKE SURE it's propylene glycol as their is more than one version of "marine" AF. Only propylene glycol is good for the engine - the other style will cause corrosion in an engine.

Blowing the faucet lines out is fine, as long as you don't have any big dips where water can accumulate. This will change from one boat to another. But, yes, blowing out the line can be just fine - it just takes a little homework the first time to make sure there are no "gotcha" areas. Even though it worked last year, do your homework this year and check things out. You might very well be fine... or you might have gotten lucky!

Personally, I like seeing that nice pink (the AF I use is pink) color come through each faucet. I open every faucet till the tank is dry and then I pump AF through each faucet. I used to simply remove the cold water pickup line from the tank and just stick it into a jug of AF (in essence, the jug becomes my fresh water tank). I would use about 2g of AF. This year I made a slight change and added a 3-way valve before my pump. I have a long, clear hose attached to the "3rd" way. After the tank is empty, I'll simply turn the valve and stick the hose into a jug or a bucket (that I've put a few gallons of AF into). The main reason that I did this was to be able to monitor (from up above, as opposed to always looking down into the bilge) the amount of AF left in the jugs as I went around. It's also a bit more convenient than removing the line from the tank, although the access to this in my boat is very good.

If you blow the lines out, and if you have a vaccu-flush head, flush the toilet a few times with the AF. The AF is good for the seals. Leave some AF in the bowl, as well.
 
I just added that same kind of 3-way valve in front of my freshwater pump last weekend, along with water heater bypass valves. Should help simplify the winterizing process quite a bit.
 
I bought a Camco kit thru Amazon that included water heater bypass valves and a connector hose, a 3-way valve for drawing pink from a jug instead of the freshwater holding tank, and a quick-connect fitting to blow out the water lines (about $40 bucks for the kit). I installed all the fittings two weekends ago in about an hour, then drained and winterized the freshwater system last weekend. Everything worked very well; it's basically the same kind of setup I had when I owned a travel trailer.
 
MikeWood said:
I like this idea too! Where did you get the 3-way valve? Any tricks to getting it installed?
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Sorry - missed this. Like Kilroy, the kit I used came from Camco, as well. I'll see if I can get a picture later. But their website is camco.net - BOE marine might even carry it.
 
I don't use pink for the water... I use compressed air connected to my shore water connnection... I don't have the bypass the heater, I just blow it dry... I also disconnect the Water pump and blow throught the lines leading in and out of the water pump. You should not blow through the water pump...
 
rcknecht said:
I don't use pink for the water... I use compressed air connected to my shore water connnection... I don't have the bypass the heater, I just blow it dry... I also disconnect the Water pump and blow throught the lines leading in and out of the water pump. You should not blow through the water pump...
Click to expand...

I am curious to know why this may be a problem ?
 
Brian 59 said:
I am curious to know why this may be a problem ?
Click to expand...

If you don't bypass the hot water heater, blowing out the lines that feed hot water throughout the boat will be difficult.
 
gerryb said:
If you don't bypass the hot water heater, blowing out the lines that feed hot water throughout the boat will be difficult.
Click to expand...

I thought he meant it would damage the pump in someway. It just so happens that I am having trouble with mine now pumping the antifreeze through the system and I cleaned the intake strainer also.
 
If you blow out through your shore water connection you don't need to by-pass the HW tank. However, you will need to separately blow lines to and from the water pump from you water tank. When you use the shore water connection it bypasses the tank and water pump. My water pump is on the fwd bulkhead in engine room. I simply spin off the connection at the pump from the tank and blow back with my air compressor. Then I spin off the line fron the water pump and blow the line from the water pump...

Regarding blowing through the pump, I was told by two different people not to blow compressed air through the water pump, as it could damage the pump. I blow through my AC pump, with no problems...
 
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