Water heater install.

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skipperdude

skipperdude

Guru
Joined
Oct 7, 2007
Messages
3,146
Location
USA
Vessel Name
Apache II
Vessel Make
1974 Donald Jones
I have a new waterheater to install. The only best place to put it is higher the engine.
The question is. Should I install a one way check valve before the water heater?

I was thinking that if the coolant started to get low it would drain out of the water heater. I thought it could air pockets.

SD
 
I absolutely would not install any check valves and it will not matter to the system if air does get in since it will be moved to the FW tank and you will get an overheat situation if you get that much air because of low coolant. Lots of boats have the hot water heat installed higher than the engine and connected to an exchanger.
 
Ours is a foot or so higher than the engines and no problems.
 
Just be sure to install the FWH on its own coolant circuit.

IT can NOT go in a circuit used for boat heating as many FWH limit the flow when a set temp is reached.

Newer engines will operate pressurized and above 212F,boiling is normal cruise coolant temp.

FF
 
Hurricane hydronic systems*can indeed be plumbed to heat* both WH and engine (if desired when at rest). When engine running hot water is available from engine for both WH and boat heating. Id assume same for Webasto etc.
 
All of the hydronic systems allow the hot water heater to be plumbed into the system. Chuck
 
FF wrote:

Just be sure to install the FWH on its own coolant circuit.

IT can NOT go in a circuit used for boat heating as many FWH limit the flow when a set temp is reached.

Newer engines will operate pressurized and above 212F,boiling is normal cruise coolant temp.

FF
I don't understand. on its own coolant circuit.* I have two hose comeing off the engine. Would I run a T? can I not run a contunious loop? I.E. engine to water heater to red dot to engine.* A red dot is just a fan on a condenser. generally used on trucks
SD
Click to expand...

*


-- Edited by skipperdude on Friday 22nd of January 2010 02:16:10 PM
 
A T would work fine or the other possibility is to set up the HW heater so it wont choke off the circ water to limit FW temperatures , not all do.

IF you chose this option and small kids are aboard a trip to the box store for an anti scald valve is in order.!!!!

These will add some cold to the HW to prevent serious burns from at least 180F water.
 
SD, Since you did not get your question answered, if you are using the Red Dot, keep in mind the flow from the engine will diminish as you add longer runs to the lines. This will lessen the heating and at some point cause cooling issues with the engine. You must run a continuous loop from the engine for this to work and of course the engine needs to be running. A Hydronic system is different in that it has a water pump and a separate heating system, but you probably already know that. Chuck
 
Chuck,
You say it would cause cooling issues with the engine. How so? I am and have had some issues. The reason I thought the one way valve would correct the issue

SD

-- Edited by skipperdude on Wednesday 27th of January 2010 12:48:39 PM
 
The problem becomes in trying to get the coolant pushed through much longer runs than the pump would normally have to circulate. In order for the coolant to properly cool the engine it needs to circulate at a correct rate. Perhaps this is over simplification but take the heater off line and connect your coolant hose to the engine as close to normal as possible and see if your problem goes away. There can be several issues to cause overheating but a one way valve will not help and if the valve fails, they do on a regular basis, you will have worse problems. Chuck
 
If the coolant system was full i.e. all the hosesfull of coolant. Would it matter how much the pump can pump as long as pressure was not an issue. Or would it be?

*As it is I am not trying to creat a pressure washer.**Just circulate coolant in a closed system. That is why I thought a one way valve would prevent the coolant from draining back into the expansion tank. My thinking is that if it started at a static ammount of coolant the pressure would not be an issue.
SD
 
The pump was designed to push the coolant through the system at a certain rate and you have added hoses and distance that was not designed into the pump thus reducing the fresh water flow rate. It does not matter whether the hoses and coolant are full. You are asking the water pump to do more than it was designed for. There is always a built in safety factor but but at some point you can exceed that. If the fresh water that comes through the heat exchanger is not cooled properly and hotter than specs it will not cool the engine and this heat will build little by little. The end effect is the same as having low coolant. Chuck


-- Edited by Capn Chuck on Wednesday 27th of January 2010 02:43:10 PM
 
Gotcha..
*I checked with the marine tech support At N.C. Machine in seattle The tec guy told me there should not be a problem. He said that the pump pressure is at 27p.s.i. more than enough. His directions were to run the engine to 1200 r.p.m. with the cap off. to bleed the air. he also recommended I install an over flow bottle to the exchanger.*Thanks for the input to help me figure this out. Some times you just have to know what questions to ask.

*Having some one to help gets the ducks in a row is all that is needed. Thanks*

SD***
 
Yes, the issue does not come up unless you are using really long runs. Many times the problem is presented when the heater is higher than the engine and the air is not purged. You can add a bleeder valve at the highest point to help with filling the system. But even filling the engine in a normal course of events requires that most of the air be bled. Depending on the engine it might move the air into the FW tank but some are very finicky and need to have all of the air purged manually. Chuck.
 
Considering that heater loops are in parallel to the normal coolant flow, there is no issue with length, size, height, location, or anything else as far as the engine is concerned.

Any additional hose simply represents a larger quantity of coolant and anything that blocks or restricts coolant flow through the heater just means that normal coolant flow occurs as if it were not there. After all, if you didn't have a water heater installed,*would your engine overheat? If you isolate your water heater does your engine overheat?

Unless you install a heater loop that has larger hoses and a larger heat exchanger*coil*than the water pump discharge size - in other words, unless it is easier for coolant to go to the water heater than the engine, this argument is bogus.
 
Rick,
*** How do you mean paralell. The hose runs off the engine to the water heater to the*heater**or red dot heater if you will. Then back to the engine. Perhaps I am not understanding your comments. As it appears to me the coolant runs in a continues loop Directly off the engine.
SD*
 
I just have two hoses the same size running off the engine* Supply and return.
*No keel cooler just a heat exchanger*** cat 3208n.a.

SD**** I think I gotcha the other is a short hose about 6" x 1 1/2 long off the raw water pump.
confuse.gif


-- Edited by skipperdude on Thursday 28th of January 2010 02:38:35 PM

-- Edited by skipperdude on Thursday 28th of January 2010 02:42:52 PM
 
skipperdude wrote:

Rick,
*** How do you mean paralell. The hose runs off the engine to the water heater to the*heater**or red dot heater if you will. Then back to the engine. Perhaps I am not understanding your comments. As it appears to me the coolant runs in a continues loop Directly off the engine.
SD*
Click to expand...
You take the coolant from an area of high pressure such as a temp sensor plug or another plug on or near the pump discharge, run it through the heater coil and return it to a lower pressure area such as a manifold or other spot with a plug near the last place the coolant flows before going back to the suction side of the pump. I have yet to see an engine that does not have a couple of plugs that will work for this purpose. If you remove a temp sender, install a*street T*so you can take water out and still use the sensor in the same location.
If you take it from existing plugs the heater is in parallel, it is not in series with the pump*and does not become part of the engine cooling loop. There is no failure mode other than leaking all the coolant out, and if*you place a valve where you take the plugs out you can isolate the heater and nothing is changed.*
 
oldfishboat wrote:

The aux 3/8 hose will be parallel to the 1, 1/2 hose in flow to and from the engine.

I think I have that correct.
Click to expand...

*Yup, you got it. If the water heater or bus heater were not there the engine would never know the difference.

I just read the engine is question is a 3208 NA, there should be taps up the ying yang on that engine, coolant temp and pressure out and return, places on the manifold, places where the turbo coolant would come and go if it was turboed, more plugs to play with than Ernistine's swithchboard.
 
Woah!! *your scaring me dude.
*I am no way a mechanic. I can see the sea water pump hose that goes into the heat exchanger bonnet.* and to the heat exchanger. I do see a plug at the base of the exchanger opposit the bonnet would that work? Or is there something else. looks like I am going to have to study this engine a little more. I really need to get a Cat mechanic to look this over for me. If I can find one to go to Whittier. To tell the truth I am not even sure what pump you are talking about. I'm gonna give up on this one.* Way over my head. But thanks just the same. I do appreciate it

SD
 
skipperdude wrote:I'm gonna give up on this one.*
Click to expand...

*Oh, don't do that. Give me a couple of days to find a 3208 and take some pictures for you to show where you can connect the hoses. It really isn't a big deal and you will have a much better idea of how your system works if you do it yourself.
 
Cool,
I'm with you on that one Thanks man. I'm here m-f 6a to 2p
Saturday sun on the boat.

SD
 
Way cool,
I can turn a wrench but I sure need to know what I am doing first.
SD
 
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