March AC Pump

[wunderluster]

This is related. If I do what I'm thinking of doing I may start having problems. I'm seeking experience anyone has had with teeing off the seacock for the manual head to supply a 500 gpg March pump for the AC.

I used the head seacock for the AC with the intention of using an unused seacock in the cockpit to supply the head. Well, I just discovered I will have to remove the battery bank, including the box, then drill a hole in the side of the engine bilge to route the new hose to the head. Or, I may be able to route the hose around the rear of the cockpit, along side the engine bilge, through the main bilge, then upto the head.

So, I'm thinking of teeing off the original seacock for the head that now supplies the AC.

Am I asking for trouble?

[AnchorageGuy]

Originally Posted by wunderluster

This is related. If I do what I'm thinking of doing I may start having problems. I'm seeking experience anyone has had with teeing off the seacock for the manual head to supply a 500 gpg March pump for the AC.

I used the head seacock for the AC with the intention of using an unused seacock in the cockpit to supply the head. Well, I just discovered I will have to remove the battery bank, including the box, then drill a hole in the side of the engine bilge to route the new hose to the head. Or, I may be able to route the hose around the rear of the cockpit, along side the engine bilge, through the main bilge, then upto the head.

So, I'm thinking of teeing off the original seacock for the head that now supplies the AC.

Am I asking for trouble?

Our boat has been set up that way since the AC was installed by a previous owner in 1986. The water comes in from the seacock, through a strainer, then runs to a tee which connects to the AC pump. The tee is connected to an elbow which goes to the head intake. An added plus is that when the AC pump needs to be primed, all it takes is to flush the head a couple of times. We have had the boat for three years living aboard so it gets a workout and there have been no issues with the head or the AC. And yes you can flush the head when the AC pump is running. Chuck

[wunderluster]

Wow! That is good to hear. All I need is a 3/4 tee to complete that setup. I wonder if West Marine will let me return 15 feet of hose

Thanks Waterwayguy.

David

[poshman]

Originally Posted by chrisjs

I have this problem repeatedly. I have found that even a small amount of air in the inlet strainer head is enough to cause the pump to not prime. I now know that after traveling, I should release air from the top of the adjacent strainer by loosening the cap. The pump then runs just fine. Provided we do not move the boat, the system usually runs OK. I think air gets entrained as the boat moves through the water. Problem is I do not feel comfortable running the AC/heat while underway, though this is usually not a problem. I would check for an air space first. It is the easiest thing to fix!!

I woke up this morning to a low flow discharge. I have a March AC-5C-MD 17gpm circulating pump feeding three air conditioners. The pump was making some noise. I thought it sounded like noisy bearings. So, I put some 3 In One Oil into the two oil holes on the pump housing. Still no improvement in the discharge. Then, I came here and read ChrisJS's comment and advice.


Even before oiling the pump, I cleaned the strainer with no improvement. During the strainer service, I did not notice any water dripping; so I didn't really think that there was an air leak. Still, in light of Chris' suggestion, I went back to the strainer.


I removed the lid on the strainer and carefully inspected the gasket under magnification and good light. Under light I could see that there were cracks in the gasket. Indeed, the back of the gasket had adhered to the underside of the lid, making it impossible to remove without damage. I ended up having to use a power drill with a steel brush to clean out the old gasket from the gasket bed.


Then, a short trip to the hardware store, where I found a "close enough" gasket that I was able to trim with a utility knife to a size where it would lay into the gasket bed. I had to buy a pack of five gaskets, but they still only set me back $5.


After laying in the make-shift gasket, I locked the strainer lid down with the new gasket, fired up the pump and "Voila"; there was a robust discharge from all three outlets!


That noise I had heard, which I thought sounded like noisy bearings, must have been the hiss of air in the impeller. After the gasket replacement, there was no such hiss and the pump sounded fine.


Thanks to Chris for pointing me to a simple fix on a very hot day!!

[Scott Berg]

Observation: while CAL pumps will indeed work we replace a dozen CAL's for every MARCH pump...

[svHyLyte]

Originally Posted by Scott Berg

Observation: while CAL pumps will indeed work we replace a dozen CAL's for every MARCH pump...

Cal Pumps are designed for submersed use and water cooling. They overheat when not used in that manner which causes differential expansion of the case, rupturing the seals. March Pumps are air cooled and if oiled every few months with a few drops of 3-in-1 oil, they will last nearly forever.

FWIW...

[Sailmonkey]

Originally Posted by svHyLyte

Cal Pumps are designed for submersed use and water cooling. They overheat when not used in that manner which causes differential expansion of the case, rupturing the seals. March Pumps are air cooled and if oiled every few months with a few drops of 3-in-1 oil, they will last nearly forever.

FWIW...

Except for the march pumps that are water cooled........but those have cooling passages and will never expand and dump oil in the bilge like the cal pumps.