Re: [Amel Yacht Owners] Flushing the AC system with Barnacle Buster

Mohammad Shirloo

Thanks Mark for the detailed explanation.
Mohammad and Aty
B&B Kokomo
Amel 54 #099

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Friday, April 13, 2018 10:47 AM
To: amelyachtowners@...
Subject: [Amel Yacht Owners] Flushing the AC system with Barnacle Buster


Mohammad and Aty,

Hope this helps…

I use barnacle buster to flush the air-conditioning system. As others have mentioned this is basically a phosphoric acid solution. For the engine and genset I prefer to dissemble the heat exchangers and clean the various components away from the engine.   I prefer not to put acid in the strainer to clean the engine/genset as this is all connected to the water-maker.

On the 53SM the air-conditioning is cooled by circulating saltwater in one loop to all three units. The aft unit is first in the cooling cycle the forward unit is last. I am uncertain if other Amel models have the same set up. To flush the air-conditioning cooling system: I disconnect the outlet hose from the 220v air-conditioning cooling pump (this is the blue Calpeda pump if you have original equipment).  This would be the INPUT hose to the AC cooling loop. I then disconnect the hose from the through-hull in the forward cabin. This would be the OUTPUT hose of the AC cooling system. I make one continuous loop with a pump and these two ends. I set up a bucket in engine room that will have a hose (with filter) to a 220v water pump (I purchased a continuous run impeller sump pump from a hardware store with water hose connections and a regular water hose to make the loop). The pumps out hookup it is connected to the INPUT hose in the AC loop. Then I run a hose from the OUTPUT through the boat back to the engine room and into the bucket thus completing the loop. I add the Barnacle Buster Concentrate to the bucket according to the instructions and assume there is about 2 gallons of water in the system. Make sure a large fan is running to vent the engine room or place the bucket in the cockpit. It is not good to breathe the fumes. I run the pump for about 4-6 hours and flush the system. The longer the better. The cycle: Bucket – Pump – AC INPUT – AC unit 1 – AC unit 2 – AC unit 3 – AC OUTPUT – Bucket. It is truly amazing what comes out and makes its way to the bucket. I made a mesh filter to catch bits from the return hose so the solids do not re-circulate.  When done, reconnect the hose ends to the through hull and AC cooling pump. Turn on the air-conditioning to flush out any remaining barnacle buster.

This is pretty much an all day project and best done when at dock.

With best regards,



Sailing Vessel - Cream Puff - SM2K - #275

Currently cruising - Guadeloupe

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Wednesday, April 11, 2018 10:30 AM
To: amelyachtowners@...
Subject: RE: [Amel Yacht Owners] Dessalator Operational Question


Hi Porter;

Can you please explain how you run the barnacle buster through the systems. I'm interested in the exact process you use. Also since this is an acid, does any one have any input on the potential down side?


Mohammad and Aty

B&B Kokomo

Amel 54 #099

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Wednesday, April 11, 2018 4:32 AM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Dessalator Operational Question


Hi Mark and Debbie. 

This is exercised induced angina!  I agree with Mohammad and Aty but also consider that 

in short, could you have calcium build up in the non Volvo raw water side?  I’d disconnect the water maker (mark of cream puffs sage insight) . Run acid (barnacle buster) through the ac/ refrigeration and Onan systems and see what comes out then flush.   I see improvement in our  systems when I run barnacle buster, things get colder more quickly. Use less power. And I also see lots of calcium come out!  

Minutes later....

Upon further reflection. I’d really have a close look at the raw water distributer and everything that connects the high pressure pump to the Seachest. 

Hope you guys are well. 


Ibis 54-152. 

Iles de saintes. 

Excuse the errors.  

Sent from my IPhone 

On Apr 11, 2018, at 1:53 AM, 'Mohammad Shirloo' mshirloo@... [amelyachtowners] <amelyachtowners@...> wrote:


Hi Brass;

Each of the systems you are running together require a healthy source of raw water to run. At the end of the season we run fresh water through all systems. We run each system individually so we can keep up with water demand. We accomplish this by shutting off the main sea water valve, removing the sea chest cover and using a 3/4 inch hose to supply the fresh water. We can run all systems individually with just one 3/4 inch hose at full flow. However, the Volvo running at idle requires more water than the single hose can provide. Therefore we use two hoses and by reducing one down to half flow, we can keep a constant water level in the sea chest.

The point being that the Volvo at 1250 RPMs (much more water requirement than at idle), the A/C and water maker running together will require a large flow of raw water. I would start by looking at anything that could restrict this flow. From the raw water valve not opening completely when you turn the valve, a rubber supply hose failure on the inside, a kink in the line, etc. I would also try shutting off the main sea water chest valve, remove the raw water supply to the LP Dessalator pump and turn on the sea water valve to see what kind of flow you are getting to the LP pump.


Mohammad and Aty

B&B Kokomo

Amel 54 #099

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Tuesday, April 10, 2018 7:17 PM
To: amelyachtowners@...
Subject: [Amel Yacht Owners] Dessalator Operational Question


We have an A54 with a 230v 160 LPH Dessalator, water cooled air conditioning, and a Volvo 110 HP engine. 

1) When operating the Onan, water maker, and the Volvo above approximately 1250 RPM the low-pressure gauge on the water maker drops from 20 psi to negative 10” hg, the high-pressure pump starves, and the water maker shuts down.

2) When operating the Onan & water maker everything operates correctly IF the air-conditioning is started first.  If the water maker is started before the air conditioner when the water maker is started the low-pressure pump pressure drops and the water maker shuts down due to low-output pressure on the high-pressure pump.

All tests were run with a clean sea strainer and a clean raw water intake pipe, it was scrubbed with a round brush that reaches through the hull.

What has been your experience?  Any thoughts?  Thanks in advance.

Mark & Debbie Mueller

A54 – 68

Brass Ring

Ft. Lauderdale

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