Water chiller air con question

Mr Googler

Mr Googler

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I have a condaria air con / heating system on the boat that I am attempting to re commission.

I got the fresh and sea water pumps going (both siezed) and started to fill the fresh water system. These feed the air handling units of which there are 4. The fresh water pressure wouldn't hold so on checking the front cabin was somewhat flooded!

I have removed the unit and the radiator (sorry if that's the wrong term) is leaking like a sieve.

One of the other units is not really needed so can I remove that one to use in the front cabin and simply join the in and out water pipes together?

Also, does anyone know what the fresh water pressure should be? The gauge is MH2O I think.

I think the chances of finding a replacement radiator are very slim but will make a few calls. Cheapest option is the swap.

Any comments welcome
 
Chilled water Air-con works akin to hot water central heating, but with cold air the result rather than hot. Swapping the units should be straightforward as would valving off an unneeded unit off, as long as the main flow to the other units remains working.

Sounds like a split coil, which is possibly repairable - try a local car radiator specialist.

The system requires flow rather than too much pressure, likely around 1 bar suction side of the pump and say 2 bar after.
 
Thanks for the reply.

Will at least get a quote for repair.

Am I best blocking the feed and return pipes off or joint them together?
 
+1 to above, said humbly because superheat is the proper expert on airco round here; I'm not. . Each of the "radiators" (usual term is air handler) is normally connected to flow and return in parallel, like a domestic radiator system. Therefore blocking off (using the valves, hopefully) the flow/return to the unit you are removing makes more sense than joining the two pipes together ( but either solution would work).

Mine is pressurised by a tee'd off pipe ( with valve) going to the domestic cold water system. I turn off the freshwater pump and open the valve and the domestic fresh water puts around 1.2 bar static pressure into the chilled water loop. Then close valve and turn the chilled water pump back on. That works fine and gives the pressure values superheat mentions above, approx. You need an accumulator in the chilled water loop- I hope there is one installed in yours.
 
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I do indeed have a fresh water feed with valve and an accumulator.

I will blank off for now and see if I can get the rest of the system to actually work.

If there are other, larger issues as let's face it, the system is close to 30 yrs old, I was thinking of finding another method for heating the water and still using the current air handlers. I don't have a huge requirement for air con in the Irish Sea. Heating is a different story!
 
I removed the air handler and found a good size hole in the matrix. Hopefully this can be soldered so will look into that.

I joined the lines together and the system now holds pressure no problem.

I have 4 lights on the control panel. Fresh and sea water pump lights on, compressor light not on and a big red "pressure block" light is on. This has been the case since first getting it going.

What does pressure block relate to and what / how is it reading this. I have 1.5 bar of pressure in the system, the sea water pump gives a good constant flow out the side so I'm a little stuck.

I have opened the bleed points on all the handlers. It is of course possible the fresh water pump impeller is fubar and note superheats comment on flow rather than pressure but thought I'd ask before taking it apart.
 
I've no idea how I would get antifreeze in there to be honest. It was also made in 1988 so liability is probably not an issue anymore :) Once it's going, I will certainly look into antifreeze, thank you..
 
I was thinking so. Just want to confirm what "pressure block" means. I have pressure in the system but perhaps it measures flow or feed and return pressure.

Was also thinking an air lock perhaps.
 
On the chilled water system it is important that the flow and return legs can actually flow, therefore either one air handler must be open or there might be a bypass valve at the end of the run. This is to avoid the pump deadheading if all the AHUs shut down, assuming they have individual flow control valves.

Assuming the red high pressure light is part of the chilled water system, this suggests overpressure, but I doubt that at just 1.5 bar. However, is this combined with the chiller controls, as this could be a High pressure warning from the fridge system. Running hot means running at high discharge pressure, so for instance if the seawater pump were off with the compressor on, up goes the HP (discharge pressure, high pressure or head pressure - all the same thing). If it is a fridge side HP trip often there is a manual reset somewhere.

On smaller boat style units these are often a small transducer style switch, with a small rubber reset button on one side opposite the threaded connection to the system, and there will normally be an electrical cable connection to the switch. They will usually reset with a click if they have operated.

I will see if I can find a typical switch and post a photo here.

Here you go - typical Manual reset HP switch ...
 
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Thanks for that. So the red light is nothing to do with how well the freshwater pump is pumping?

The compressor light is off and given it has been like this from day one, I will look for a reset button. As the seawater pump was siezed it could have been like this for years!
 
It sound like you unit is the same as mine.
As you look at the front panel with the four lights, the pressure reset switch is on the top of the frame, on the left hand side as you look at it. A little black rubber nob on top of a metal box. Press it firmly and this should reset the switch
 
I found the reset button on a box with settings for lp and hp pressures and ranges.

That did nothing so I manually pushed in the compressor relay. The compressor cut in for a very brief moment then the shore power tripped.

It's not looking good really is it.

Still, 27 years old is not bad going. Thanks for all the comments and I'll keep having a dig around but I fear it may be terminal. I might start another thread looking at options. I have an idea in my head for fitting a second calorifer and using the existing pump and handlers to pump warm water round the current system so that I have heating.
 
Generally the idea is sound, but there are some control issues to think about. You will kill the chiller compressor stone dead if you try to get it to cool water fed in much above 30oC, and definitely at 40oC +.

This means a method of preventing the chiller running at all if you have the system in heating mode.

Your start load anyway will be quite high for the compressor, so see what rating & curve your shore supply breakers are. Ideally 16a D Curve, C might be OK, B Curve too light. The curve controls how fast a breaker trips. Motors require a higher curve, and high torque motors like compressors push the limit.

But also check what else is drawing power, as even a base load somewhere else of just a few amps could cause the draw to exceed your allotted 16 amps, or whatever MCB size the marina have fitted.

Our own yard was rewired earlier this year with 16 amp B curve MCBs. Fine for us casual users, but for the live aboards with washing machines and dryers, for ever hopping ashore to reset the damn thing.
 
FARSCO said:
I found the reset button on a box with settings for lp and hp pressures and ranges.

That did nothing so I manually pushed in the compressor relay. The compressor cut in for a very brief moment then the shore power tripped.

It's not looking good really is it.

Still, 27 years old is not bad going. Thanks for all the comments and I'll keep having a dig around but I fear it may be terminal. I might start another thread looking at options. I have an idea in my head for fitting a second calorifer and using the existing pump and handlers to pump warm water round the current system so that I have heating.
Click to expand...

What is the shore power? Standard uk 16a won't be enough - I know cos I tried it on holiday.
You need 32a to run the AC unit. The compressor started and the shore power tripped so I think the unit is probably good. You likely need 32a supply
 
Interesting.... Would the shore power being to light (16a) cause the red pressure block light to be on? Should the compressor even try to run and then trip as its doing nothing.

It only tripped when I manually operated the relay for the compressor. Not sure I have the bottle to try that on the Genny.

I could run it from the generator to see if it will kick in. Do I need to press the rest button whilst it's running?

I took some pictures which I will try to post.
 
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