thermostat - water heater connection

[KWKloeber]

Is it because the coolant only circulates in the water heater loop AFTER the thermostat opens?

NO. The WH loop is below the TStat so coolant (heatant?) circulates immediately.
THAT's the beauty of how the WH is plumbed. The OLD m-25s (C-30s) the WH was plumbed in series with the Hx, and one COULD NEVER get hot water at idle, only when underway w/ a load on the engine.

The coolant flows from the engine block, to the base of the water flange, to the WH, back to the coolant pump, back into the block. If you LOOKED AT the coolant flow diagram I prepared, that's evident that the TStat is out of the loop as far as heating domestic water.
Sometimes there's an air lock in the coolant pump itself and the impeller cannot push water thru the engine block. Make sure it's filled full.

You can expel a lot of air at the pressure cap.  Open, rev the engine, level will go down and add coolant.  As you keep circulating (there is a bypass at the TStat so some coolant ALWAYS flows) air can bubble out at the open cap.

The key others are saying is make sure you fill everything to the extent possible before burping. See the instructions.

If the other heater is plumber in THAT could be affecting how quickly or if at all the WH heat up.  If the return hot water line from the WH is hot, then heatant is getting there and back to the engine.

[waughoo]

Alex- You are "the hardest working guy in show biz..." 
if you ever get tired of the NW weather come on down to San Diego. I have plently off hoses you can change!

Noah... I cant say I want to do that again anytime soon!!  However, it makes me very happy to know their condition.  The boat was not well maintained by the last owner so I have chosen to basically do a restoration of sorts of all the systems.  I used all spiral wire hose and it was actually a treat to work with. 

I had a bit left over and decided to also replace the propane locker hoses.they were pretty crappy.  Well, that single job was almost harder than the whole errffing engine hose job.  It was like part boat yoga mixed with a rubix cube (I have a 1.5).  That locker the box sits in is crazy small for the box.  I then went to put the lid on and THAT required passing it from the stbd locker to the port behind the radial wheel and then over tk the fuel tank area, up the hull into the coaming and then back down on the box.  This puzzle took me a full 40 minutes to sort out. 

[KWKloeber]

And which hose did you replace?

The large 7/8" hose that is about 2-3 foot long and carries coolant from the pump to the heat exchanger was the hose we replaced.

That 7/8" hose (there's three of them) is the RETURN from the Hx to the engine block. It's important that hose be wire wound because it's a suction hose.  It's like a lower radiator hose in an auto.
Again
https://groups.io/g/Catalina30/wiki/9626
it's helpful to understand the intricacies of our engines, if nothing more than to make future troubleshooting quicker when time is of the essence (like overheating while in a "delicate" situation on the water.)

[Ron Hill]

Guys : The easiest way I found to "Burp" the water heater, was to connect a small Japsco PAR hand pump to the return water heater return line (off the engine pump).  With a short hose from the PAR output into the coolant reservoir - I just pumped (circulated) the engine coolant until I got a steady flow of coolant without air bubbles!  Simple as that!!

A thought

[waughoo]

I like that idea Ron!  Stored away for next coolant system opening.

[junaido]

Since this whole issue really started with the nipple pulling out along with the hose, I have become very averse to hose pulling methods to bleed air out of the coolant system. I am going to resort to petcock in the future. Maybe try that contraption that is mentioned elsewhere that can be fitted in the thermostat pet cock opening.

[Stu Jackson]

Since this whole issue really started with the nipple pulling out along with the hose, I have become very averse to hose pulling methods to bleed air out of the coolant system. I am going to resort to petcock in the future. Maybe try that contraption that is mentioned elsewhere that can be fitted in the thermostat pet cock opening.

junaido,

I respect and understand your reasoning.

Perhaps you may want to reconsider the reasons for your decision, because I think the way you got to it is actually a GOOD thing since you found a problem and fixed it by being proactive.

What I can share are my own experiences over 24 years of ownership and being a BMW. 

Soon after we bought our boat I was motoring in the Oakland Estuary, off our marina, going to visit a friend in an adjacent marina maybe five minutes or so away.  My engine overheated.  I was lucky is was a Tuesday morning with very little traffic.  I shut the engine down and carefully watched that the current wasn't setting me into harm's way.  Even then (19998 or 9) I had read ALL of the existing tech notes, since the PO was kind enough to save all of the Mainsheet magazines ]including the tech notes] from when he bought the boat in 1986.  I remembered the suggestions to use the petcock on top of the thermostat to bleed the air out, so I removed the companionway steps and turned her back on, revved her up from the cockpit (I hadn't yet learned how to do it from right at the engine), and popped the petcock.  It took a few trips up and down to do this.

Since that experience, I was acutely aware of the difficulties of using the petcock,, since I was stupid and didn't use an oven mitt to do that.   

I was hoping that someone would come up with "A Better Way."

And Ron Hill did.  The minute I read his suggestion of filling the hose(s), I was convinced.  Because one of the first things I needed to do was to replace my anemic 2" HX with a 3" HX, I, of course, had to drain my coolant.  I saved most of it, using the technique I photographed years later in that linked 101 Burp thread.  I have been using it, successfully, ever since, over two decades, and have replaced the hX a few times for various reasons documented on this forum.

I simply recommend to you that instead of NOT using something that works better than the petcock without installing anything else, you consider using what 30 years of experience has taught us.

I am aware of Maine Sail's suggestion of using an automatic air vent for that purpose.  I have seen photos of it.  If I had a link, I'd include it.

The reason I don't have a link immediately at hand is because I am convinced one of those really neat fittings would simply NOT fit on the top of our engines with the steps right above it.  It might work on a C36 or a C30 but I really don't think it would on our boats.  Indeed, if it would so easily, I haven't heard of anyone installing one.

Why?  Maybe because it won't fit (if it did I'd bet a whole bunch of us would have done so, similar to routing the air breather hose to the engine intake).  But perhaps more importantly, is that Ron's method, pump or not, simply works.

As always:

Your boat, your choice. 

[KWKloeber]

I am aware of Maine Sail's suggestion of using an automatic air vent for that purpose.  I have seen photos of it.  If I had a link, I'd include it.

The reason I don't have a link immediately at hand is because I am convinced one of those really neat fittings would simply NOT fit on the top of our engines with the steps right above it.  It might work on a C36 or a C30 but I really don't think it would on our boats.  Indeed, if it would so easily, I haven't heard of anyone installing one.

Why?  Maybe because it won't fit (if it did I'd bet a whole bunch of us would have done so, similar to routing the air breather hose to the engine intake).  But perhaps more importantly, is that Ron's method, pump or not, simply works.

Stu,

Are you referring to this?

https://c34.org/bbs/index.php/topic,5508.msg34381.html#msg34381

https://c34.org/bbs/index.php/topic,4518.msg38110.html#msg38110

https://c34.org/wiki/index.php?title=ONE_PROCEDURE_TO_FLUSH_the_ENGINE_CLOSED_COOLANT_SYSTEM_-_from_RC%27s_(aka_Mainesail_aka_Rod_Collins_aka_Compass_Marine)



If there's a tight fit could there be an elbow atop the housing (orient the cock horizontally)?

Recently someone said he was going to install it, but CRS whomever it was.
OMG it was Mike Brown in May 2017.  Time flies by.  I dunno whether he did go that route but I'll ask him.

I dint recall RC saying it's automatic, but it does make it a titch easier (clean up, recovering any blown off coolant.) Sorta like the fuel bleed knob rather than the bleed screw that tends to blow fuel/air down the engine.

[junaido]

Stu,

Thanks for the detailed reply. I agree that there is no room under the companionway steps for anything but the petcock, but I was thinking of using mainesail's contraption as a temporary thing to be screwed in when bleeding air and then replaced with petcock. Does that sound feasible?

Junaid

[KWKloeber]

Mike Brown has NOT installed RC's super duper bleed valve system so no joy there.

[Stu Jackson]

Stu,

Thanks for the detailed reply. I agree that there is no room under the companionway steps for anything but the petcock, but I was thinking of using mainesail's contraption as a temporary thing to be screwed in when bleeding air and then replaced with petcock. Does that sound feasible?

Junaid

You're very welcome.

That "contraption" is actually a very standard plumbing and mechanical fitting used in all closed systems to purge air.  They make manual as well as automatic ones.  As you can imagine, the automatic ones are used more often because the high points of building systems aren't always easily accessible. A manual one would work on an engine.

However, there seems to be another inconsistency at play here.  If your concern is still about the fitting that disintegrated on you (and which remains quite valid), it would seem to me that even thinking about taking off yet another fitting (the petcock) to temporarily replace it with another one (the vent) is counter-intuitive.

Why go to all that effort? 

All you have to do is remove one hose from a hose barb, fill it up (by gravity or a small hand pump), and replace it.

I forgot to mention in my last post:  I slather a bit of Lanocote inside the ends of all my hoses before I put them on hose barbs.  It makes it much easier to remove them when, not if, they have to be removed.  I've never had any problems backing that 3/8" hose off the thermostat.

If you still don't want to do that, then stick with just using the petcock.  My experience is that it takes a few revs while the engine is busy getting itself overheated, to purge the air out that way.  I thought about it and figured, why not just get the air out first?  And avoid any and all overheat...

Please continue to think this through.

[waughoo]

[quote author=Stu Jackson
I forgot to mention in my last post:  I slather a bit of Lanocote inside the ends of all my hoses before I put them on hose barbs.  It makes it much easier to remove them when, not if, they have to be removed.  I've never had any problems backing that 3/8" hose off the thermostat.
[/quote]

I SO SERIOUSLY considered doing this when replacing all my hoses.  I was too impatient to slow down and go get the lanicote.  I kick myself now that I'm not in the engine bay wresteling the beast.  It is SUCH a good idea.  I did however change out my tstat housing bolts to allen socket head cap screws and slathered them and the tstat housing holes with tefgel .  So at least that shouldnt be a problem in the future.