Hi Marek,
You're right on, the only issue in my mind is that the coolant must run from
the top of the engine, down under the floorboards to then get to the hot water
heater which is above the floorboards, thus causing an inherent desire for the
air to form a pocket above the floorboard level before dropping back down to go
back to the engine. Slow water flow would result in a permanent air pocket,
but robust water flow *should* push both coolant and remaining air out. Not
sure how much flow it would take to accomplish that...
I agree that the in/out coolant is probably on the back of the unit where I
can't see it, and that was a great suggestion by the list.
Thanks all!
Bruce Whitmore
(847) 404-5092 (mobile)
bwhitm...@sbcglobal.net
On Thursday, May 16, 2019, 8:49:39 PM EDT, Marek Dziedzic via CnC-List
<cnc-list@cnc-list.com> wrote:
Bruce,
The water heater is a pretty basic device. And it seems that all of them (most
of them?) look and connect in a similar way.
You have cold water in, hot water out (usually cold water lower than hot),
pressure relief valve, drain. The coolant in and out can be on the same side
(front) or at the back (most vendors offer both models). I don’t believe that
there is any difference which is in and which is out for coolant (the heat
exchanger is pretty simple inside).
I don’t believe you will need to purge the air from the water side of the
heater. The air should come out through your taps. If in doubt, you can always
open the pressure relief valve (as Josh suggested) and if the water flows you
are done.
The bigger problem might be purging air from the coolant side. It really
depends on where the heater is located. Some boats have it located high up
(well above the engine). It does not look like that from your photo, but just
in case. If this is the case, you need to have a purging valve next to the
heater. I have seen the heaters installed like that (in the lazarette). In that
case, you had to purge the air at the heater and the engine had to be run at
fairly high revs (2500?) in order to push the coolant all the way there.
If the heater is at the same level as the engine, you should be able to purge
the air through the normal filler cap (no additional work required; the air
will escape to the overfill tank).
Hope it helps
Marek
From: CnC-List <cnc-list-boun...@cnc-list.com>On Behalf Of Ken Heaton via
CnC-List
Sent: 16 May, 2019 20:12
To: bwhitmore <bwhitm...@sbcglobal.net>
Cc: Ken Heaton <kenhea...@gmail.com>; cnc-list <cnc-list@cnc-list.com>
Subject: Re: Stus-List Purging air from Attwood EHM6-SM Water Heater
This is the best I could find:
http://productimageserver.com/literature/ownersManual/35883OM.pdf
Ken H.
On Thu, 16 May 2019 at 21:09, bwhitmore <bwhitm...@sbcglobal.net> wrote:
Ken, that makes total sense into me. Now if I can find the coolant hoses!
I'm really surprised I can't find good installation instructions!
Sent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------
From: Ken Heaton via CnC-List <cnc-list@cnc-list.com>
Date: 5/16/19 6:37 PM (GMT-05:00)
To: cnc-list <cnc-list@cnc-list.com>
Cc: Ken Heaton <kenhea...@gmail.com>
Subject: Re: Stus-List Purging air from Attwood EHM6-SM Water Heater
I think you have the following ports visible in your photo:
H = Hot Potable Water out of Heater to your hot water taps.
C = Cold Potable Water into heater from the potable water pump.
D = Drain for emptying the Heater of Potable Water for winterizing.
P1 = Pressure Release Valve for an over-pressure condition caused by the
electric element sticking on and boiling the contents of the Heater.
If you also have in and out for Coolant so the engine can heat the water they
must be out of sight on the rear?
What Josh said about using the Pressure Relief Valve will bleed air our of the
Potable Water section. It won't bleed the coolant loop from the engine.
Ken H.
On Thu, 16 May 2019 at 18:29, Bruce Whitmore via CnC-List
<cnc-list@cnc-list.com> wrote:
Hello all,
I think I probably have some air trapped in my hot water heater. I have found
some pretty cryptic instructions for the heater, but:
a). They do not include a good drawing or explanation of how the hoses, either
fresh water or coolant should be connected (yes I have looked for better online
instructions to no avail)
b). They say "Bleed air from the entire coolant system for proper operation of
both engine and water heater", but don't give instructions as to the best way
to do it.
c). They do not include a listing of the what the stamped letters next to the
outlets mean. (the upper left in the photo is "H", bottom left is "D", upper
right is "P1" and lower right is "C"
Here's a photo of the water heater: Attwood EHM6-SM Water Heater.j
The tube in the upper left feeds the boat with hot water. I think the tube on
the bottom with the valve on it comes from the engine hot water feed. I turned
off the valve, and the hot water continued to run, so it is definitely not the
fresh water supply line to the heater. And, having a valve on the hot coolant
input line would make sense. Therefore, am I correct in thinking the pipe on
the lower right would be the return coolant line to the engine?
Now for conundrum #2.
Here's a photo of the hoses leading out of the engine. Hot water heater hoses
at engine.jpg. Those hoses connect to the grey solid pipes shown in the
previous picture, somewhere under the floorboards where I can't see which is
which. They were disconnected, but filled with coolant when I got the boat, so
I was just guessing when I connected the hoses to the engine. In looking at
the Yanmar manual, it appears the red hose should be the suction side coming
from the water heater, and the black hose would be the pressure (hot) water
coming from the engine to the water heater. Am I correct?
Any way about it, since the water going down to the heater must flow down under
the floorboards, up to the heater, then out of the heater and back down under
the floorboards, the water heater would be a prime spot for air to get trapped.
So, I am thinking I should ease off the connection coming off the lower right
side of the heater and apply pressure to the appropriate hose coming off the
engine, and see if I get any air out. Then, I want to ensure I am connecting
the correct hose to the right inlet/outlet point on the engine. Does this make
sense?
Thanks for your insights!
Bruce Whitmore
(847) 404-5092 (mobile)
bwhitm...@sbcglobal.net
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every one is greatly appreciated. If you want to support the list - use PayPal
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Thanks everyone for supporting this list with your contributions. Each and
every one is greatly appreciated. If you want to support the list - use PayPal
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