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Help me plumb my heater!


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The circled port is where I think i'm supposed to put one of my hoses. Correct? I have what I assume to be a temp sensor there. How should I plumb this side?

20160516_062930.jpg

I will be using a low idle y on the return. Should I do anything with this side of the engine? Should I plug the 2 holes connected by the hose with the red line drawn? 

20160516_062847.jpg

Lastly, I want to add a valved bypass circuit for winterization or in case the heater core fails. What's the simplest way to do that? I saw a thread on here about it awhile ago, but can't find it now...

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1 hour ago, Ndawg12 said:

Your second pic shows where I accessed mine?  Do you have a shower or what is that hose feeding?

No shower. You can see both ends of the hose in that pic, although it's difficult to tell from the angle. One end goes into the manifold on the port side, and the other end goes into the water pump (at least I think it's the water pump)

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No idea why that would be running to your raw water pump.  Both of my installs, in that port was just a plug which I had to fashion some nipples, couplings, 45/90's and a ball valve in order to route it out from under the intake plenum and up towards the core.   The wye fitting goes in the line between your vdrive and raw water pump with the smaller 5/8" port angled towards vdrive.  There was a good DIY thread posted years ago that I modeled both of my installs from, I'll try to find it.

 

 

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I saw that thread, but I coulda sworn I saw another one where the intake was tapped from the starboard side. Will that one ball valve be enough to shut off the heater circuit and keep the block properly cooled if something happens to the core? Some months ago I saw a writeup that showed pics of a pretty elaborate shutoff circuit... 

So if I copy 09vride's setup, I need to plug the port on the water pump?

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53 minutes ago, Chatty21VLX said:

I saw that thread, but I coulda sworn I saw another one where the intake was tapped from the starboard side. Will that one ball valve be enough to shut off the heater circuit and keep the block properly cooled if something happens to the core? Some months ago I saw a writeup that showed pics of a pretty elaborate shutoff circuit... 

So if I copy 09vride's setup, I need to plug the port on the water pump?

I have no idea what that would be running to your raw water pump.  If you can't figure it out then I'd get in there and take some detailed pics and post them up before disconnecting anything.  I you put that ball valve in on the supply side then you just need another ball valve shortly after the wye fitting in order to isolate or cut off the the heater circuit, essentially returning the engine's water flow pattern back to stock.  I mounted my core in the observer compartment so it's easy to just unhook 2 hoses once a year so no help there.  

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When I bought the boat, it already had a heater. The fan motor worked, but the core was ruptured. I'm pretty sure the hose is there from the previous owner bypassing the bad core. It's running from the top of the starboard side intake to the port near the thermostat housing to a port on the raw water pump. I'm also pretty sure the port on the raw water pump that the hose is going to is the port you would use for the return if a low idle y isn't installed. The old heater hoses were just laying in the bilge, not attached to anything on the engine end. 

Maybe I should ask it this way: in a stock setup, with no heater, does the raw water pump and top of the starboard side on the intake just have a plug in those ports?

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What you are referring to as a raw water pump is actually the water circulating pump. In a stock set up there are plugs in the intake and in the water circulating pump. Apparently because the original heater was removed the hose between the heater supply on the intake manifold and heater return in the water circulating pump were just looped together. Use the hose from the intake as your heater supply. Remove the fitting from the circulating pump and install a plug and plumb the return to the "Y fitting you are going to install.

  • Like 1
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  • 3 years later...

Holy thread resurrection, Batman! I actually am just now getting around to plumbing this heater... The fitting on the circulation pump is giving me fits. It's too close to a metal bracket to get a box end wrench on it. I can't get the open end on it without removing the muffler. I can't get it with an adjustable wrench or tongue and groove pliers. It's a PITA, basically. What are my options now? Can I put a tee in there to supply the heater core? Should I put a short piece of hose on the fitting and add some type of plug? I kinda need to figure out something soon, or I'll have to put everything back together and not have a heater til I decide to try again. 

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I think you are saying that you got the plug out, but can't tighten the new barb in place.  Either way, something has to give.  I see no reason to cobble a solution when you could remove the bracket, the muffler, or the pump to get it installed. 

What is the bracket holding? 

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No, I didn't get the plug out. I'm trying to remove a fitting to install the plug. There's a reducer screwed into the circulation pump, and a 3/8" elbow screwed into that. The spot where I need to connect the supply hose already has a fitting installed. I gave up last night because it was getting dark. I think if I get that elbow out, I might be able to use a socket for the rest. I honestly didn't look to see what the bracket was holding because I really really don't want to have to remove a bunch of stuff for this. 

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On 9/22/2019 at 7:55 PM, Chatty21VLX said:

Holy thread resurrection, Batman! I actually am just now getting around to plumbing this heater... The fitting on the circulation pump is giving me fits. It's too close to a metal bracket to get a box end wrench on it. I can't get the open end on it without removing the muffler. I can't get it with an adjustable wrench or tongue and groove pliers. It's a PITA, basically. What are my options now? Can I put a tee in there to supply the heater core? Should I put a short piece of hose on the fitting and add some type of plug? I kinda need to figure out something soon, or I'll have to put everything back together and not have a heater til I decide to try again. 

Same for me too this is what I did ,  capped it off with hose and npt fitting snd cap with Teflon tape , as you can see this is the return ,  supply shouldn’t be the issue I’m assuming 

i just thought I was a pitiful jackleg mechanic with no skills 

you should be installing the heater y pipe I’m assuming 

mid this is full install then use the heater Y to do return snd you only have to worry about supply line opposite 

CE944311-1BEE-4F48-AFB9-F75FBC9F1BF0.jpeg

F3EE0F4E-607F-4292-A4C1-B6172B95B48C.jpeg

Edited by granddaddy55
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You're OK just plugging your existing fitting or the hose like @granddaddy55 did.  That's a suction side hose so it's never under any positive internal pressure.  The heater is fed by the barb that's screwed into the top of the engine block next to the Tstat housing.

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6 hours ago, UWSkier said:

You're OK just plugging your existing fitting or the hose like @granddaddy55 did.  That's a suction side hose so it's never under any positive internal pressure.  The heater is fed by the barb that's screwed into the top of the engine block next to the Tstat housing.

I’m thinking he has nothing to plug cause he had no heater,  I’m wondering if he can’t get some sort of hex plug out to get return and feed,  he can ignore the return snd use a Y pipe but he needs to get the feed one off ,  is he struggling with the to heater fitting ?

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4 hours ago, granddaddy55 said:

I’m thinking he has nothing to plug cause he had no heater,  I’m wondering if he can’t get some sort of hex plug out to get return and feed,  he can ignore the return snd use a Y pipe but he needs to get the feed one off ,  is he struggling with the to heater fitting ?

I did have a heater, but the core was busted. I'm pretty sure the previous owner installed the bypass hose from the circ pump to the manifold. I couldn't get the elbow fitting out of the circ pump. After half a can of WD-40, some prayers, and a lot of grunting and elbow grease, I finally got it out. Was able to install a plug and finally plumbed the heater. I installed the low idle wye between the v drive and impeller. I haven't been able to test it yet, but I'm sure it will be fine. Still need to add some quick hose disconnects for easy winterizing and bypass of needed.

  • Like 2
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19 hours ago, Chatty21VLX said:

I did have a heater, but the core was busted. I'm pretty sure the previous owner installed the bypass hose from the circ pump to the manifold. I couldn't get the elbow fitting out of the circ pump. After half a can of WD-40, some prayers, and a lot of grunting and elbow grease, I finally got it out. Was able to install a plug and finally plumbed the heater. I installed the low idle wye between the v drive and impeller. I haven't been able to test it yet, but I'm sure it will be fine. Still need to add some quick hose disconnects for easy winterizing and bypass of needed.

You won’t believe just how well the Y works, makes hot under way and very warm at idle 

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