Dometic Marineair problem.

[wyctoronto]

It’s a 2005 16,000 BTU unit. I can’t get antifreeze from the input to the output through the unit. Have disconnected both hoses right at the unit but can’t get flow either direction. Any ideas? Does anybody have a technical support number for Dometic. Their website seems to direct me to a vendor. Thanks.

 

[Scott T-Bird]

I will be curious if you get any information. Just last Saturday, I had no flow thru my 12,000 BTU unit (1999). It seemed like the raw water pump was trying to pump water thru but I couldn't determine if there was a blockage. I was running heat just the week before. I've heard that the reverse cycle valve can get jammed sometimes when reversing from air condition to heat. But I had no problems with this up until last weekend.

 

[wyctoronto]

Mine also was working fine just before hauling out; that’s why it’s confusing !!

 

[Davidasailor26]

Air conditioning pumps are not self priming, and getting them to pull antifreeze can be tricky. When the boat is in the water the pump is usually below the waterline, so water naturally flows into it. Even then it’s often necessary to open a bleed valve to let the air out of the pump so water can start flowing. When out of the water it’s even harder to get antifreeze through to prime the pump.

If you have two people you can try having one pour antifreeze into a long neck funnel and into the intake hose, while the other person turns on the AC and opens the bleed valve long enough to bleed the pump, and then close it while AF gets circulated.

I usually winterize by myself, so I use an aquarium pump to help push the AF through. I put the pump output onto the AC input, and pour AF down a funnel while the pump and AC run. With that the aquarium pump generates just enough pressure to keep the AF flowing.

 

[wyctoronto]

Air conditioning pumps are not self priming, and getting them to pull antifreeze can be tricky. When the boat is in the water the pump is usually below the waterline, so water naturally flows into it. Even then it’s often necessary to open a bleed valve to let the air out of the pump so water can start flowing. When out of the water it’s even harder to get antifreeze through the to prime the pump.

If you have two people you can try having one pour antifreeze into a long neck funnel and into the intake hose, while the other person turns on the AC and opens the bleed valve long enough to bleed the pump, and then close it while AF gets circulated.

I usually winterize by myself, so I use an aquarium pump to help push the AF through. I put the pump output onto the AC input, and pour AF down a funnel while the pump and AC run. With that the aquarium pump generates just enough pressure to keep the AF flowing.

View attachment 235321

Thanks, but I’ve tried pumping from the unit itself both ways from the input and outflow connections. Antifreeze won’t go thru the unit.

 

[Davidasailor26]

Thanks, but I’ve tried pumping from the unit itself both ways from the input and outflow connections. Antifreeze won’t go thru the unit.

Ah, well that is strange. I think the reversing valve Scott mentioned is just for the refrigerant, not the water, so I don’t think that would be involved. I don’t have any other explanation for what might suddenly block the water flow through the unit.

 

[kloudie1]

As David says, the reversing valve is in the refrigerant circuit and not on the water side. The condenser water side is a pipe that should be open from end to end. There are no valves, so the only thing that could block it would be if the refrigerant side pressure collapsed the inner water pipe (highly unlikely) or something from the haul-out (stuff on the slings?) plugged it. You could try to push a 10 or 12 gauge wire in from one end then the other to see if you can find, identify, clear the blockage. I dunno. Some condensers use a rippled tube but most are a simple pipe with no "turbulators" inside. Good Luck.

 

[wyctoronto]

As David says, the reversing valve is in the refrigerant circuit and not on the water side. The condenser water side is a pipe that should be open from end to end. There are no valves, so the only thing that could block it would be if the refrigerant side pressure collapsed the inner water pipe (highly unlikely) or something from the haul-out (stuff on the slings?) plugged it. You could try to push a 10 or 12 gauge wire in from one end then the other to see if you can find, identify, clear the blockage. I dunno. Some condensers use a rippled tube but most are a simple pipe with no "turbulators" inside. Good Luck.

Thanks I’ll give I a try.

 

[Rich Stidger]

I believe that you have a air-lock in the pump. The solution is to attach a hose to the intake and raise it several feet higher than the pump. Use a funnel and pour AF into it as previously suggested. Alternatively, you could attach a hose to the input of the strainer and use a drill-powered pump to push AF into the system.
If everything was working prior to haul-out, I think it is unlikely that you have a blockage.
For future winterizing, get a 5 gallon bucket and install a hose barb near the bottom. Then run a hose from that barb to the strainer input. With the bucket several feet higher than the strainer and pump, fill the bucket with AF.

 

[wyctoronto]

I believe that you have a air-lock in the pump. The solution is to attach a hose to the intake and raise it several feet higher than the pump. Use a funnel and pour AF into it as previously suggested. Alternatively, you could attach a hose to the input of the strainer and use a drill-powered pump to push AF into the system.
If everything was working prior to haul-out, I think it is unlikely that you have a blockage.
For future winterizing, get a 5 gallon bucket and install a hose barb near the bottom. Then run a hose from that barb to the strainer input. With the bucket several feet higher than the strainer and pump, fill the bucket with AF.

Thanks but I’ve tried pumping using another pump directly at the input and outflow on the unit itself both ways. So something within the unit is preventing flow.

 

[Rich Stidger]

Thanks but I’ve tried pumping using another pump directly at the input and outflow on the unit itself both ways. So something within the unit is preventing flow.

Was the pump you used a positive displacement type or a centrifugal type? The centrifugal type will not build pressure, just like the A/C pump.
If you have a bicycle pump with a gauge, try attaching that to see if you can build pressure. If pressure won't build, then you do not have a plug. Or at least not a total plug.

 

[wyctoronto]

Thanks for all of your support. I tried Kloudie1’s suggestion and was able to dislodge whatever was in the way using a length of 10 ga wire. I was then able to blow the remaining water out and ran some antifreeze through the unit. Problem solved. Cheers to those who took the time to help.

 

[kappykaplan]

I tried Kloudie1’s suggestion and was able to dislodge whatever was in the way using a length of 10 ga wire. I was then able to blow the remaining water out and ran some antifreeze through the unit. Problem solved.

Well done!

 

[Rich Stidger]

Thanks for all of your support. I tried Kloudie1’s suggestion and was able to dislodge whatever was in the way using a length of 10 ga wire. I was then able to blow the remaining water out and ran some antifreeze through the unit. Problem solved. Cheers to those who took the time to help.

Were you able to determine what the plug was?

 

[wyctoronto]

Were you able to determine what the plug was?

No, very little came thru but didn’t see anything that could have gone thru the strainer. Maybe air locked??

 

[BigEasy]

No, very little came thru but didn’t see anything that could have gone thru the strainer. Maybe air locked??

Perhaps there was marine growth / barnacles that clogged the lines. In the Spring, after launching, might be a good idea to flush the lines with a solution, such as barnacle buster or mild acid solution.

 

[wyctoronto]

Perhaps there was marine growth / barnacles that clogged the lines. In the Spring, after launching, might be a good idea to flush the lines with a solution, such as barnacle buster or mild acid solution.

We’re in fresh water but that’s a good idea for my spring list