OK. The Yanmar 4JH4 is on the stringers, exhaust run to the waterlock and
raw water hose is on the strainer. Now I turned my attention to running
hoses to the water heater at the back of the engine compartment. The
instructions suggest that to avoid air traps the hoses to the heater should
be run below the level of the engine heat exchanger. BUT the inlet and
outlet for the water heater feed is on top of the pump which is at the top
front of the engine!

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

As long as the cooling system's header/expansion tank is even higher than
the highest point of the water heater loop, would adding a valve or two for
burping the heater loop do the trick? You might even get by with plugs on
tees.


"Glenn Ashmore" wrote in message
news:1Gzyf.8431$Dh.3554@dukeread04...
OK. The Yanmar 4JH4 is on the stringers, exhaust run to the waterlock and
raw water hose is on the strainer. Now I turned my attention to running
hoses to the water heater at the back of the engine compartment. The
instructions suggest that to avoid air traps the hoses to the heater
should
be run below the level of the engine heat exchanger. BUT the inlet and
outlet for the water heater feed is on top of the pump which is at the top
front of the engine!

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

Probably not a significant concern. As long as expansion tank is properly
located. Almost all automotive heaters have some or all of their plumbing
higher than the radiator.


"Jim Conlin" wrote in message
...
As long as the cooling system's header/expansion tank is even higher than
the highest point of the water heater loop, would adding a valve or two
for
burping the heater loop do the trick? You might even get by with plugs on
tees.


"Glenn Ashmore" wrote in message
news:1Gzyf.8431$Dh.3554@dukeread04...
OK. The Yanmar 4JH4 is on the stringers, exhaust run to the waterlock
and
raw water hose is on the strainer. Now I turned my attention to running
hoses to the water heater at the back of the engine compartment. The
instructions suggest that to avoid air traps the hoses to the heater
should
be run below the level of the engine heat exchanger. BUT the inlet and
outlet for the water heater feed is on top of the pump which is at the
top
front of the engine!

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

Glenn,

I have always been amused by instructions like those you reference. The
notes usually make it sound as though nothing in the route could be
above the expansion tank (deaereator). - Nice Trick

I'm going to assume you want to know what matters.

The manufacturer is afraid that the disharge from engine may no be able
to push "over the hill".

Just do your best to avoid Big High loops in the routing. The jacket
water pump is capable of pretty good discharge head, and that only
really matters until the cooling system is full. An air bubble would
have to be really something to prevent the jacket water from flowing all
the way through the loop. Lots of the cars built everywhere can't be
completely filled from the pressure cap.

If you have to go up a foot from the engine connections, no big Whup.
Just be sure to bleed the hoses at start up and keep a eye at the
deaereator level for the first few hours.

Good Luck Guy - I've been watching.

Matt Colie

Glenn Ashmore wrote:

OK. The Yanmar 4JH4 is on the stringers, exhaust run to the waterlock and
raw water hose is on the strainer. Now I turned my attention to running
hoses to the water heater at the back of the engine compartment. The
instructions suggest that to avoid air traps the hoses to the heater should
be run below the level of the engine heat exchanger. BUT the inlet and
outlet for the water heater feed is on top of the pump which is at the top
front of the engine!

The JCCs once had a lecture by a sewage engineer describing anecdotes from
his many years of experience. One comment he made which was later
reinforced by my father's comments is that, for low pressure flow, a "hump"
in the line can entrap an air bubble which will block the flow
significantly.

Dad was describing the miseries of covering for those rotten architects that
decided to save money on a high-rise by reducing the pitch of the floors.
Without enough equipment space above the ceiling, the various plumbing and
electrical runs and (his concern) the HVAC ducts had to have all manner of
humps and dips to cross each other and these could lead to for both
installation and maintenance. The Marina Towers in Chicago had a
ventilation blower with a 4' wide filter and only 3' beside it in the
equipment room. To change it required folding and contortions. Kroschell
Engineering (his firm) was called in to make the system work after the
initial, low bidder, was thrown off the job. The drain pipes were a
particular concern because humps like those mentioned above were forbidden.

So maybe your 3" hose looks like a 1" hose if you don't run it well.
Entrained air will form a bubble.

Roger

http://home.insightbb.com/~derbyrm

"Matt Colie" wrote in message
...
Glenn,

I have always been amused by instructions like those you reference. The
notes usually make it sound as though nothing in the route could be above
the expansion tank (deaereator). - Nice Trick

I'm going to assume you want to know what matters.

The manufacturer is afraid that the disharge from engine may no be able to
push "over the hill".

Just do your best to avoid Big High loops in the routing. The jacket
water pump is capable of pretty good discharge head, and that only really
matters until the cooling system is full. An air bubble would have to be
really something to prevent the jacket water from flowing all the way
through the loop. Lots of the cars built everywhere can't be completely
filled from the pressure cap.

If you have to go up a foot from the engine connections, no big Whup. Just
be sure to bleed the hoses at start up and keep a eye at the deaereator
level for the first few hours.

Good Luck Guy - I've been watching.

Matt Colie

Glenn Ashmore wrote:

OK. The Yanmar 4JH4 is on the stringers, exhaust run to the waterlock
and raw water hose is on the strainer. Now I turned my attention to
running hoses to the water heater at the back of the engine compartment.
The instructions suggest that to avoid air traps the hoses to the heater
should be run below the level of the engine heat exchanger. BUT the
inlet and outlet for the water heater feed is on top of the pump which is
at the top front of the engine!

Glenn,
I ran heater hose up about 18" then over about 15 ft and back down to the
water heater in the opposite hull of my cat. It works fine, but I made sure
there was no air in the line when I hooked it up by filling the entire run
with a funnel on one hose end. The water heater was slightly lower than
either engine, though.

"Glenn Ashmore" wrote in message
news:1Gzyf.8431$Dh.3554@dukeread04...
OK. The Yanmar 4JH4 is on the stringers, exhaust run to the waterlock and
raw water hose is on the strainer. Now I turned my attention to running
hoses to the water heater at the back of the engine compartment. The
instructions suggest that to avoid air traps the hoses to the heater
should be run below the level of the engine heat exchanger. BUT the inlet
and outlet for the water heater feed is on top of the pump which is at the
top front of the engine!

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Garland Gray II" wrote ...
Glenn,
I ran heater hose up about 18" then over about 15 ft and back down to the
water heater in the opposite hull of my cat. It works fine, but I made
sure there was no air in the line when I hooked it up by filling the
entire run with a funnel on one hose end. The water heater was slightly
lower than either engine, though.


That is encouraging. My installation will not be that bad. Only about 6'
to the heater. No room for an expansion tank at the high point so I may
just add a couple of bleeder valves there.

This is getting to be a real pain now that the engine is blocking the best
access to the engine compartment. I have to lay on an aft bunk and slide my
head and shoulders into the access hatch to do anything. Inevitably once I
squirm into position I find that I have the wrong size wrench!

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

Glenn Ashmore wrote:
"Garland Gray II" wrote ...

Glenn,
I ran heater hose up about 18" then over about 15 ft and back down to the
water heater in the opposite hull of my cat. It works fine, but I made
sure there was no air in the line when I hooked it up by filling the
entire run with a funnel on one hose end. The water heater was slightly
lower than either engine, though.



That is encouraging. My installation will not be that bad. Only about 6'
to the heater. No room for an expansion tank at the high point so I may
just add a couple of bleeder valves there.

This is getting to be a real pain now that the engine is blocking the best
access to the engine compartment. I have to lay on an aft bunk and slide my
head and shoulders into the access hatch to do anything. Inevitably once I
squirm into position I find that I have the wrong size wrench!

My Yanmar 1/2/3 GM installation manual allows you to have
the heater inlet/outlet up to 0.5m above the water pump
inlet as long as the overflow tank is installed above it,
and have a air bleeder valve at the heater.

Sorry about the constriction in your engine compartment. On
my boat I don't have a "compartment", I just lift a
mattress and the engine is there. I can almost stand up
beside it. Typical cat elbow room will make maintenance so
easy (o.k. except for Yanmar's stupid water pump impeller)

Evan Gatehouse

"Glenn Ashmore" wrote in message
news:MIWyf.8530$Dh.7045@dukeread04...
SNIP
This is getting to be a real pain now that the engine is blocking the best
access to the engine compartment. I have to lay on an aft bunk and slide
my
head and shoulders into the access hatch to do anything. Inevitably once
I
squirm into position I find that I have the wrong size wrench!


I've concluded that for such jobs one needs a thinner and younger helper.

I am beginning to envy Skip. With that center cockpit and deep bilge Flying
Pig's engine compartment is bigger than an average size stateroom. :-)

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Jim Conlin" wrote in message
. ..

"Glenn Ashmore" wrote in message
news:MIWyf.8530$Dh.7045@dukeread04...
SNIP
This is getting to be a real pain now that the engine is blocking the
best
access to the engine compartment. I have to lay on an aft bunk and slide
my
head and shoulders into the access hatch to do anything. Inevitably once
I
squirm into position I find that I have the wrong size wrench!


I've concluded that for such jobs one needs a thinner and younger helper.