AC Pump Not Pumping

[jimL]

Hi there,

We have four HVAC units on board that are provided water from one pump. Two days ago I noticed two of the HVAC units were not putting out the usual amount of heat (I usually one use those two units). This morning I realized there is no water circulating. I verified the strainer is clear, seacock is open and the is water coming in (I tested it).

The pump goes on, but no water comes out and two of the four HVAC units will not cycle on (they are new this year). The pump sounds like it's pumping but no water comes out. The pump is below the water line by at least 18".

Any thoughts about next steps?

Thanks - JimL

 

[boatnbump]

Does it have a bronze impeller. I had one like this and the impeller was deteriorated. If so you will be surprised at how well the A/C works when you get a new pump. I think mine had not been pumping correct for a long time.

 

[Porgy]

Is or was there a leak? Is there a bleed screw on the pump? Open it and see if any air comes out before a solid stream of water.

 

[jimL]

Porgy and Boatbump, thanks for the suggestions. We're in transit right now going to Isle of Hope from Hilton Head - will check the bleed screw when we get there.

If I do need a pump - does anyone have an idea of where to get one?

Thanks - JimL

 

[Woodstock]

Are you getting an HPF error on the controller(s)? By the look of that tag the pump is from Scot? If it is, you can probably get parts from them. They're great to work with and will also help you troubleshoot.

 

[Porgy]

I once contacted Scot Pump and yes, they were very helpful and responsive. They are in Ft. Lauderdale. They also recommended Depco in Clearwater for parts.

 

[Porgy]

The only seawater issue I’ve had is operating in shallower water and sucking up a stirred up bottom which can eventually stop water flow. I’ve needed to backwash the lines with a garden hose from time to time.

 

[tiltrider1]

Diagnostics routine - pull exit hose on pump. Does water squirt out when pump is running?

No - pull inlet hose. Does water squirt out? No - clog. Yes - impeller or bleed issue.

Yes - replace hose. Pull hose from hvac inlet. Does water squirt out when pump is running?

No - clog in line.

Yes - hvac is frozen up. Possibly from barnacles, ice if running as a heater and low water flow or packed full of corrosion.

 

[backinblue]

In my limited experience/knowledge, A/C water pumps are often not self-priming so that could be an issue if boat was hauled. Disconnecting/loosening the hose from the pump outlet may get it working.

 

[Comodave]

In my limited experience/knowledge, A/C water pumps are often not self-priming so that could be an issue if boat was hauled. Disconnecting/loosening the hose from the pump outlet may get it working.

Agree, that is the first thing I would check.

 

[ScottC]

In my limited experience/knowledge, A/C water pumps are often not self-priming so that could be an issue if boat was hauled. Disconnecting/loosening the hose from the pump outlet may get it working.

Yes - a good (and rather easy) thing to try! I have to do this nearly the start of every season after launch.

 

[Iggy]

I would open the sea strainer again. My last boat I had to open it a few times before it would pump water. Just a thought............

 

[Comodave]

Do the simple stuff first when troubleshooting. So prime the pump, or make sure it is primed. Then if that doesn’t work go on to the more in depth things like clogged lines, etc.

 

[jimL]

Thanks for all of the suggestions.

I cleaned the sea strainer on Monday before we departed Charleston. The HVAC units seemed a bit weak (warm air) Tuesday morning at our anchorage. I may have gotten some air introduced when I cleaned out the strainer. Once the engine room cools a bit I will try to bleed the air at using the bleeder valve at the top of the output hose.

This is another example of how valuable this forum is.

We are currently at Isle of Hope Marina in Savannah - going to ride out tomorrow's weather. We're headed to an anchorage Friday and hoping to do an outside run to Frenandia Beach Saturday. Would be interested in linking up with any TF members.

Thanks again - JimL

 

[Pete Meisinger]

Mine will occasionally lose its prime. Sometimes I have to remove the intake hose and "force feed" it. Sometimes I can get by with just giving the intake hose a solid squeeze.

pete

 

[Comodave]

Check the prime first. Then if you have access to a garden hose maybe hook it to the hose coming from the pump and see if you get water flow with dockside water pressure. You can clamp off individual hoses if there is more than one A/C to see if water flow is good. Also if there are any partial clogs it may blow the hose clear. Then get into the more difficult things.

 

[slowgoesit]

Porgy and Boatbump, thanks for the suggestions. We're in transit right now going to Isle of Hope from Hilton Head - will check the bleed screw when we get there.

If I do need a pump - does anyone have an idea of where to get one?

Thanks - JimL

Try this one:

https://www.amazon.com/dp/B007BVKAQA?psc=1&ref=ppx_yo2ov_dt_b_product_details

$68.00, free shipping from Amazon. 700 gph.

We are using the 500 gph Danner pump on our 16.5k btu and it works great. 700 gph pump should be able to do two HVAC's, provided the hose run is not too long. They are self priming, but they should be installed below the water line.
Alternately, you can buy an AC pump "specifically for marine air conditioners/heaters" They run North of $150.00, some WELL North!
The one above is for salt or fresh water, uses a magnetic drive coupling, and I'll just carry a spare pump, still for less then the cost of one of the more expensive ones!

 

[Comodave]

Depco is a good source for pumps.

 

[jimL]

Thanks everyone.

I let the air out of the outlet side of the pump using the bleeder valve and we're back in business! I have never had that happen before - air lock after cleaning the strainer. This was a lesson learned for me and now I have a checklist of actions to take should I run into something like this in the future.

Many thanks - JimL

 

[Porgy]

Good news. I’d want to know why you lost prime. Did it happen immediately after a haulout or cleaning the strainer? Or manifest itself sometime later out of the blue?

I’ve only ever had to bleed the pump after a haulout. Now I close the seacock before getting hauled and open after launch. After cleaning the strainer, I put the cap on loosely then open the seacock and tighten the cap when water flows out.

 

[Comodave]

Glad you got it fixed. Always start with the simple stuff first.

 

[rgano]

I have what at least for this forum is a fairly uncommon problem with my air conditioner. EVERY time I launch from my boat lift there is air in the system. An associated issue is the nearness of the pump to the waterline - nothing can be done about that, but I have lowered the strainer to the lowest point possible while still maintaining a constant rise with no high spots from the sea cock to the pump. I have a bronze grating mounted over the exterior mushroom of the sea cock mounted in reverse so that it scoops water into the system when underway, but if conditions are such that getting underway to force water through is unfeasible, I have installed a ball valve on a tee at the pump's exit which I open within seconds of turning on the AC unit to quickly bleed any air from the system.

 

[TowLou]

Glad you got it figured out sorta. Was going to suggest first check if the pump is primed if you hear it.

Next to figure out how you lost your prime.

 

[backinblue]

I have what at least for this forum is a fairly uncommon problem with my air conditioner. EVERY time I launch from my boat lift there is air in the system. An associated issue is the nearness of the pump to the waterline - nothing can be done about that, but I have lowered the strainer to the lowest point possible while still maintaining a constant rise with no high spots from the sea cock to the pump. I have a bronze grating mounted over the exterior mushroom of the sea cock mounted in reverse so that it scoops water into the system when underway, but if conditions are such that getting underway to force water through is unfeasible, I have installed a ball valve on a tee at the pump's exit which I open within seconds of turning on the AC unit to quickly bleed any air from the system.

Rich, wouldn't it be helpful to close the seacock before you lift the boat so that water doesn't drain out of your intake? Then open it once in the water again.

 

[Comodave]

Rich, wouldn't it be helpful to close the seacock before you lift the boat so that water doesn't drain out of your intake? Then open it once in the water again.

That is what I was thinking. Although I haven’t really had any problems with loosing prime in any of the boats we have owned.

 

[ssurabus]

I did the same/similar thing that Rich did. On a short-haul I have closed the seacock with success about 50% of the time. Having a way to bleed the air at the pump is a very nice convenience.

 

[jimL]

This only happened after cleaning the strainer - which I have done dozens of times before.

JmL

 

[Cigatoo]

This happens to me after every re launch. Sometimes just moving the hoses around to help the air through resolves the issue. Ill have to look for a bleed screw. Never realized one existed.

 

[Bacchus]

This happens to me after every re launch. Sometimes just moving the hoses around to help the air through resolves the issue. Ill have to look for a bleed screw. Never realized one existed.

Last season I added a T at the strainer with a capped hose fitting.
I did it to ease winterizing by pumping pink from my raw water system through the AC lines. I have had a couple instances where priming in the spring took some assistance and this will allow a quick / short hose connection from raw water system to prime.
It's another way to skin the cat.
I have seen other TFers add a permanent X-connect with a valve.
To me if it happens often that would be easier than messing with hoses.

 

[Cigatoo]

Last season I added a T at the strainer with a capped hose fitting.
I did it to ease winterizing by pumping pink from my raw water system through the AC lines. I have had a couple instances where priming in the spring took some assistance and this will allow a quick / short hose connection from raw water system to prime.
It's another way to skin the cat.
I have seen other TFers add a permanent X-connect with a valve.
To me if it happens often that would be easier than messing with hoses.

I have a bronze tee in the line between the pump and the ac for winterizing. Pulling that plug is plan B if moving the hoses doesn’t work.