Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 11-12-2008, 17:45   #16
cruiser

Join Date: Sep 2007
Location: Tampa to New York
Boat: Morgan 33 OutIsland, Magic and 33' offshore scott design "Cutting Edge"
Posts: 1,594
Thats the way it was set up when I bought the boat. Its the original water heater, as I mentioned earlier it is too big to get in or out anywhere, must have been put in during construction. Im assuming thats how morgan set it up at factory. But we all know about assumptions.
__________________

__________________
forsailbyowner is offline   Reply With Quote
Old 14-06-2012, 09:16   #17
Registered User

Join Date: Jan 2006
Location: Rhode Island
Boat: Tayana FD-12
Posts: 612
Images: 6
Re: Perkins 4-108 Water heater plumbing

How long does it take for water to get hot? Does it ever get hot? Do you need to be under way? can you just idle at anchor?
My engine reaches 180F at anchor idling. I've tried numerous plumbing options with water heater (6 Gal Seward products), none of which are satisfactory. Here is what I tried and my findings:

Option 1: Use Ports recommended by manufacturer, the ones in the head to feed the waterheater. One behind thermostat housing and one to the left of the thermostat housing. Observation was that at water heater inlet, hose does not get warm to the touch. Seems like there is air trapped and adding antifreeze via radiator cap on the exhaust manifold does not help. Also seems like there is barely any flow of antifreeze in this loop. Most of it goes via the 1-1/4" loop and the heat exchanger. Result was 2 hours at idle with no hot water.

Option 2: Tee off 1-1/4" heater hose between exhaust manifold and heat exchanger with 1-1/4"x1-1/4" x 5/8" copper barb tee fitting, feed the 5/8" hose to water heater. Feed 5/8" output of waterheater back to the block inlet just below alternator via another 1-1/4"x1-1/4"x5/8" tee.
10 hours of motoring and water was not warm. There seems to be no flow of hot antifreeze via the 5/8" route. All the antifreeze goes via heat exchanger and 1-1/4" route.

option 3. Use oil cooler to make another antifreeze loop between water heater, oil cooler and use separate jabsco pump to circulate antifreeze. Idea came from seeing how hot oil filter and oil hoses get. So far I got water to be luke warm after 2 hours at idle. Doesn't seem like oil has enough heat capacity to heat the water that way in reasonable time.

I am new to diesels so therefore the experimentation. But with my old atomic 4, I plumbed water heater directly inline between exhaust manifold and heat exchanger forcing all of antifreeze through waterheater and water was scorching hot after 1/2 hour of idling. This is not an option with diesel as that loop is 1-1/4" ID and water heater is 5/8".
__________________

__________________
phorvati is offline   Reply With Quote
Old 14-06-2012, 19:50   #18
Senior Cruiser
 
DeepFrz's Avatar

Cruisers Forum Supporter

Join Date: Mar 2006
Location: Winnipeg
Boat: None at this time
Posts: 7,930
Re: Perkins 4-108 Water heater plumbing

phorvati, do you realize the last entry before yours was in 2008???
__________________
DeepFrz is offline   Reply With Quote
Old 15-06-2012, 13:13   #19
Registered User

Join Date: Jan 2006
Location: Rhode Island
Boat: Tayana FD-12
Posts: 612
Images: 6
Re: Perkins 4-108 Water heater plumbing

i see, I wasn't sure if it makes sense to start a new thread?
__________________
phorvati is offline   Reply With Quote
Old 05-10-2017, 04:06   #20
Registered User

Join Date: Oct 2008
Posts: 205
Re: Perkins 4-108 Water heater plumbing

I realize this an old thread...I'd like any data avail on the best way to plump in the cvoolant lines from a 4-108 to the wwater htr.
A fitting near the thermostat seems to be the consesus for 1 end.
Then it gets a bit fuzzy.

Anyone suggest where to attach ther other hose to minimize overheating?
Bob
__________________
roberttigar is offline   Reply With Quote
Old 05-10-2017, 09:55   #21
Registered User

Join Date: Nov 2014
Posts: 608
Re: Perkins 4-108 Water heater plumbing

Here is how it was done on an engine that I had, and the same as mentioned earlier in the above thread....

- Outlet to the hot water heater- come out of the head on the threaded fitting just to the rear of the expansion tank. Normally this fitting contains the temp gauge sender, so the sender is removed and installed in a "T" where it still feels continuous flow. The other side of the "T" is sent thru a 1/8 or 3/16" restriction and then to the hot water tank. The advantage of using this source is that it flows some water to the hot water heater regardless of whether the thermostat is open or closed.

- return from the hot water heater- there was a fitting installed in the line between the outlet of the heat exchanger and the inlet to the oil/ gear box coolers. This location feels suction from the circulation pump, so the pressure in the cylinder head and the suction from the circ pump ensures circulation thru the hot water heater. If you don't have the factory fitting in this copper pipe, just make a "T" in the hose on the outlet side of the heat exchanger.

DougR
Attached Thumbnails
Click image for larger version

Name:	image.jpeg
Views:	29
Size:	209.7 KB
ID:	157174   Click image for larger version

Name:	image.jpg
Views:	32
Size:	220.9 KB
ID:	157175  

__________________
DougR is offline   Reply With Quote
Old 05-10-2017, 13:20   #22
Registered User

Join Date: Oct 2008
Posts: 205
Re: Perkins 4-108 Water heater plumbing

Thanks Doug, that's exactly the information I needed. I am going to add 1 more item to the run-a second tee so that I can install a petcock to aid in draining off any air out the system. The water lines to the heater tank are 5/8". Wil the engine run cooler if the lines are smaller dia? Bob
__________________
roberttigar is offline   Reply With Quote
Old 05-10-2017, 14:22   #23
Registered User

Join Date: Nov 2014
Posts: 608
Re: Perkins 4-108 Water heater plumbing

I think it's best to stay with 5/8 hose to keep back pressure in that loop at a minimum. But you will note that I mentioned a restriction in the hot water outlet from the head. You don't want too much flow in the hot water heater circuit because that circuit bypasses the engine heat exchanger. When the water in the hot water tank is cold, the coolant flowing to the tank releases a lot of heat into that tank, but when the tank water has heated up, very little heat is released into the water, and so that hot coolant returns to the engine. This can cause the engine to run warm if there is too much flow bypassing the heat exchanger....hence the restrictor.

You can put a "T" into the water heater circuit to aid in air bleeding, but if the hot water tank is below the level of the engine expansion tank, it isn't necessary. The system will self bleed just fine.

If the hot water tank is above the engine expansion tank you should really have a remote expansion tank to allow complete air purge in the coolant system.

DougR
__________________
DougR is offline   Reply With Quote
Old 05-10-2017, 18:30   #24
Registered User

Join Date: Oct 2008
Posts: 205
Re: Perkins 4-108 Water heater plumbing

My engine, and many 4-108's tend to run hot if you try to push it towards 2000 rpm's-at least sailboats with cruising props. Wouldn't I be better off minimizing the flow to the hot water heater so more flow runs thru the Heat exchanger? Bob
__________________
roberttigar is offline   Reply With Quote
Old 05-10-2017, 19:40   #25
Registered User

Join Date: Nov 2014
Posts: 608
Re: Perkins 4-108 Water heater plumbing

If you have a restriction of 1/4" to 5/16" in the outlet to the hot water heater, that's plenty.

The inherent problem with the rear mounted heat exchanger was that it was just too small for the amount of heat it needed to reject. Originally, I had the same problem with the engine that I had. The factory HE had a tube bundle that was 3" diameter X 9" long. I had a HE made with a 3 " X 12" tube bundle that fit in the same location as the original with just a minor hose change. This HE had about 33% more tube area and I never had a problem with overheating after that, even in the warm water of the Chesapeake Bay. I propped the engine so the max. RPM was 3400, and I could run all day at 2800 without problem.

DougR
__________________
DougR is offline   Reply With Quote
Old 06-10-2017, 05:53   #26
Registered User

Join Date: Oct 2008
Posts: 205
Re: Perkins 4-108 Water heater plumbing

Yes, I have read your old posts with interest. 1 of these days I am going to do that. Sen-dure is almost in my back yard. But for now I am ok. Unless I am running against a strong wind or current I can do 6 knts. at 1800 rpm and thats as fast as the boat will go.

I'll use 1/4" pipe off the front feed and keep the hose at 5/8". Wont be a problem with the eturn line feeding into the Crazy Tee after the oil cooler with a 5/8 hose?
Bob
__________________
roberttigar is offline   Reply With Quote
Old 07-10-2017, 09:44   #27
Registered User

Join Date: Nov 2014
Posts: 608
Re: Perkins 4-108 Water heater plumbing

Not sure what the "crazy T" is, but you should be OK returning anywhere in the return circuit from the HE to the block.

I think the factory returned between the HE and the oil cooler because that's where the best accessibility is.

DougR
__________________

__________________
DougR is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Salt water in Perkins 4-154 oil sample starfish62 Engines and Propulsion Systems 37 01-07-2009 10:20
water heater Ray Hunt Construction, Maintenance & Refit 8 23-01-2009 11:34
Conclusion [and further developments WRT KISS wind generation] (was) Re: Water Heater skipgundlach Product or Service Reviews & Evaluations 2 04-06-2007 08:31
Water Heater experience sought skipgundlach Product or Service Reviews & Evaluations 7 26-04-2007 06:13
Perkins 4-236 cooling water circuit seaclusion Engines and Propulsion Systems 0 13-01-2007 06:07



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 01:36.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.