Ranger Tug R27 AC Pump losing Prime

T

tiger

New member
Joined
Nov 30, 2020
Messages
4
Fluid Motion Model
C-28
Hull Identification Number
fmlt2747l819
Vessel Name
Ali Alkhalisi
Hello all My 27 Ranger tug R27 2019. Iam having issues with my AC water pump keeps losing prime it draw the water from the same raw water filter as the Generator. After I prime the AC pump it works fine with shore power only, but once I turn the generator on it loses the water uptake. I have never seen and AC pump share the same as the generators raw water filter???? Does anyone have a fix for this issues I can't run the AC for long when out cruising. It works much better when I change the AC raw water hose to the raw water intake of the toilet except at speed thinking about leaving it that way and put a clam shell on the hull inlet to keep water flow at speed. I sure other have had this issue please help thank you.
 
tiger":1p5jmmvg said:
Hello all My 27 Ranger tug R27 2019. Iam having issues with my AC water pump keeps losing prime it draw the water from the same raw water filter as the Generator. After I prime the AC pump it works fine with shore power only, but once I turn the generator on it loses the water uptake. I have never seen and AC pump share the same as the generators raw water filter???? Does anyone have a fix for this issues I can't run the AC for long when out cruising. It works much better when I change the AC raw water hose to the raw water intake of the toilet except at speed thinking about leaving it that way and put a clam shell on the hull inlet to keep water flow at speed. I sure other have had this issue please help thank you.
Click to expand...

Hello,

Below is a link to the Ranger R27OB, look at pages #11 and #16 to check and verify that hose routing and water routing is correct for the generator and AC pump. On page 11 it shows that the AC pump has its own dedicated strainer, which should be the case, and that the generator shares the dome/multi strainer. Let us know what you find when comparing to the diagrams in the owners manual.

viewtopic.php?f=7&t=12051

Thanks,
 
Thank you for your reply's. Yes the AC raw water hose was differently connected to the raw water filter the big dome that the Generator is connected too it looks like this was connected that way at the factory. So easy fix, I switched hoses out with the toilet intake. The AC pump works great when not moving after I prime it, however when I start moving it will lose prime underway is there a way. I think air bumbles or planning probably makes it lose prime. Is there a way to remedy this?
 
We also have a 2019 RT27 ob and my thru hull configuration is the same as Tiger. We use fresh water for the head and keep the single thru hull closed and use fresh water in a pitcher. We like a dedicated thru hull that we can keep closed (we used this process on all of our previous boats). I think the thru hull configuration is different in 2018 vs 2019 boats. We have not tried running both the gen and air at speed but this works at anchor. Our problem is cleaning the thru hull for the multi port strainer because of the clam shell with strainer. I am looking at installing a high speed Groco clam shell thru hull with a door plus strainer to allow cleaning and increasing it to 1 1/4 inches (existing thru hull is 1 inch). Groco also has a high speed non clam shell thru hull that would allow cleaning.
 
Also check the connections all along the input side. Even a slight leak will cause you to lose prime. I had to change mine out at the pump connection as it was not the right fitting. Was a couple threads to long and would not fully tighten.
 
Undersizing thru hull seacocks and utilizing single seacocks for multiple purposes is not a good Idea. Most engine manufactures, marine air unit manufactures and generator manufactures state the specific size of the required seacock and specify it to only be used for the single piece of machinery.

* THIS IS COPIED FROM DOMETIC INSTALLATION INSTRUCTIONS
Through-Hull Inlet Fitting
A separate through-hull fitting must be installed for each air conditioning seawater pump. Do not attempt to draw water from an engine, generator, or other through-hull fitting.

The multi port strainers work but in most cases marginally.

Examples: 5/8" feed for a generator, 1/2" feed for a head, 3/4 feed for a wash down pump. This is plumbed to a thru hull with a 1" diameter. I'm not an engineer but I can add. Will this work ? Probably but marginally.

1 1/4 " feed for a diesel, 1/2" feed for a head, 3/4" feed for was down pump . This is plumbed to a thru hull with 1" diameter. This is a common installation for Yanmar and Volvo's in Ranger and Cutwaters 220 hp and below. Does this work? yes but marginally.


Another issue with the install is the plumbing should be installed with the seacock at the lowest point, strainer and then the pump. All of this should be mounted below the waterline. Then a gradual incline to the air unit. The system is designed to be self draining so that no air can get trapped in the system. If the strainer or pump are higher then the air gets caught in the pump and it will not pump. It is a centrifugal pump, it cannot pump air. With a system installed that is not self draining and the pump is above the water line air can get trapped into the pump, which can happen in heavy seas or a sharp turn while operating the boat. If air gets into the pump it will quit pumping.

I have to prime my pump anytime the boat is pulled out of the water and then launched again. The water drains from the pump to seacock and from the pump to the unit. There are high and lows in the lines which prohibit self draining. Properly installed plumbing for the air unit would be self draining, purging all the air out of the system from the air unit to the seacock. When in the water and seacock is open the water would enter the thru hull ,strainer and fill pump and the air would purge out of the air unit to the discharge thru hull.


Engine installations, generator installations, air unit installations........ All have a very specific set of guidelines that should be followed. There are reasons that manufactures do extensive engineering into the products to provide trouble free operation and maintain reliability. This engineering extends to installations. The installations should be followed by the boat manufacture to the letter and if there is a variation it should not be on the marginal side but the conservative side to provide better service to the customers. Saving money up front eventually cost at the end.

There are many things that can be done to improve a system that is marginal installed. The best fix is to insure it is installed to the manufactures specifications and design.
 
Thank you all for your response. Not sure why ranger does not follow the manufactures recommendation??? I live in Florida and the main reason for this boat was the inclosed AC helm. There are 100 of boat manufactures that have AC units running on planning boating. So trying to figure the best way to set this up so I don't keep on losing prime. Lower the pump? get a new pump that will not be effected by air in the system? Clam shell on the intake under the boat? Bigger Raw water filter? If anyone has had a successful fix please share. Thank you all.
 
tiger":3bt7cqv2 said:
Thank you all for your response. Not sure why ranger does not follow the manufactures recommendation??? I live in Florida and the main reason for this boat was the inclosed AC helm. There are 100 of boat manufactures that have AC units running on planning boating. So trying to figure the best way to set this up so I don't keep on losing prime. Lower the pump? get a new pump that will not be effected by air in the system? Clam shell on the intake under the boat? Bigger Raw water filter? If anyone has had a successful fix please share. Thank you all.
Click to expand...

There are many ways to make it better but there is one way to make it right. Installation based on the installation manual.

I have installed marine air units after factory deliveries and the plumbing aspect is usually not that difficult to install in a boat that is assembled. ( the air ducting is usually a nightmare to install)

The thru hull should be mounted as deep in the water as possible. Close to the keel and a properly sized seacock installed with a scoop facing forward ( the thru hull, fittings, hoses should be sized equal to or larger than the pump inlet inside diameter). You will have to move the hose from the multi sea strainer( Generator/head/ wash down ) to the single thru hull/ strainer dedicated to the Air Unit and confirm it is properly sized.


The strainer installation should be located below the water line. There should be a straight run from the thru hull seacock to the strainer. No low spots, no loops and limited bends.

The pump inlet should be installed above the strainer but below the water line. Again no low spots, loops and limited bends to prevent air from getting trapped. When I installed this portion of the plumbing I would confirm when the seacock is opened the sea strainer and pump would fill with water and water would come out of the pumps outlet fitting( pump off). This guarantees that air will not trapped, the pump will prime, the install is done correctly.

From the outlet side of the pump to the air unit inlet ( air unit should be mounted above the water line) there should be a slight increase in hose elevation. When the pump is pumping it should be pumping up hill to the air unit. There should be limited bends, no loops or no low spots for water to trap. When the pump is off the water should drain down hill from the air unit to the pump/strainer/seacock. When the boat is pulled out of the water the system if properly installed should be self draining.

From the outlet side of the air unit to the thru hull discharge fitting the hose should be running down hill. limited bends, no loops and no low spots. This will allow any water from the air unit to thru hull discharge to self drain.

If the system is properly installed there should be no issues with air entering the pump while running at any speed. These air units are designed to be operated while the boat is operating and at speed, any speed.

No matter what others have done to fix the issues with poor air unit performance while operating the boat. Bandaids are temporary fixes. If properly installed you should not have any issues with the units operation unless there is a failed component. In your description the unit is operational the installation is prohibiting it from operating correctly.

The same goes for the generators. If the installation is installed correctly the units should operate flawlessly.

When Multi port sea strainers are ok to use with heads and wash down systems. I cringe at the thought of using them in conjunction with the main engine, generator, or Marine air units.
 
Wow Brain thank you so much for your info will be doing this ASAP. Will tell you how things turn out.
 
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