Water chiller air con question

[Mr Googler]

I did note that the pressure only rises by about 20 mh20 (or 0.2 bar) when the pump is running. Is that normal? It certainly feels as though something is stopping the compressor from even trying to start.

 

[superheat6k]

The red light is the HP warning for the fridge system. The manual reset button in the middle of the Penn dual LP / HP should clear it. Just press it in firmly with a small screwdriver. They normally click when the mechanism resets.

I would agree with Whitelighter re the power supply - 16a may just not be sufficient. Operating the relay showed the compressor worked. I expect the HP switch cuts the control feed to the relay / contactor, so manually operating it bypasses the HP cut out. I would suggest you do not permanently run it in that way.

mH2O is metres of head of water. I would expect mid gauge would be about right. A metre head of water is only a very small fraction of a bar. Quite an unusual measurement to see used.

The HP trip won't cut out instantly - it will likely take the compressor at least 1 - 2 minutes to reach trip pressure if the seawater is not circulating the condenser.

 

[Mr Googler]

Thanks again superheat. So am I right the cut out will trigger on both low and high pressure? Given the compressor doesn't even get going, out of gas?

I'll get my air con chap down.

What's the best replacement for R22 gas? Any idea on quantities in this size system. Asking a lot I know!

 

[superheat6k]

Thanks again superheat. So am I right the cut out will trigger on both low and high pressure? Given the compressor doesn't even get going, out of gas?

I'll get my air con chap down.

What's the best replacement for R22 gas? Any idea on quantities in this size system. Asking a lot I know!

Oh dear you asked the R22 question ! I will try to keep this short.

Firstly and to digress slightly - the LP will be an Auto reset, the HP a Manual reset on this dual control. But the reason I suspect your compressor is not staying on is likely the power supply limitation, rather than loss of refrigerant.

So about the R22.

It is now illegal anywhere in the EU to charge R22, but if your system already is on R22 then you can carry on running it. Take it out or should it leak you just can't put back in.

There are several gases available to replace R22, the principal issue being non compatibility of later HFC refrigerants with the simple mineral oils R22 worked so well on.

The grades that would work on your unit are from the ones we used routinely (trade names in brackets) ...

R417A (Isceon MO59); R422D (Isceon MO29); R438A (Isceon MO99). There are some other such as RS45 whose R number I cannot recall.

These get over the oil issue by adding some Iso Butane to make the oil travel around the system, BUT they are not a perfect match, and some will work perfectly well in one system, then behave like an absolute bitch in an identical system. The thing that always suffers these issues is the compressor, so once you use one of these do not be surprised if the compressor fails within a few months, and be pleased if it is still working after a year.

The major replacement for R22 was R407C, but this requires the oil from the compressor removing and replacing with a Polyolester grade, sometimes known as a POE. The problem being your hermetic compressor was never designed to have an oil change. It is also necessary to remove 95% of the original mineral oil, and this requires as several oil changes BEFORE the gas is changed.

Again the issue here is that the oil will log in the system and so will starve the compressor, likely wrecking it.

The direct replacements are still available so check what your local Fridge firm can provide. Note that when using a direct replacement the expansion device may require adjusting.

So the powers that be have now decided (F Gas Review 2014) that HFCs will now be phased out too, and the phase down has already started. There is no direct R22 / R407C gas yet available from non-HFC gases, and it is unlikely there will be, meaning at best ~ 5-10 years serviceability of former R22 / R407C equipment. However, the now common R410A is in a similar predicament, and the effect of removing these gases from the market will extend far far beyond us leisure sailors.

Politicians acting to save the Environment without suitable technical advice is going to prove a recipe for disaster.

The best bet for the short term is HFC R134a, but in your system expect ~ 30% loss of cooling capacity. R134a already has non HFC gases available from the HFO family, and is already being used in car AC systems as R1234YF. A Minor disadvantage of HFOs is that they are flammable, but I guess a few burnt down buildings, supermarkets and houses is a small price to pay for saving the environment.


You did ask !

 

[Mr Googler]

My 2014 car needed it's air con regassing. The old type would have been £50......new type £250!!! I don't think it has much to do with the environment and isn't the ozone hole shrinking anyway?

Thanks so much for your replies. I will run it off the genie and try the reset. Fingers crossed.....might just buy a fan heater and a blanket for swmbo

 

[Mr Googler]

A little update. Having got the genie running I pushed in the compressor relay and the compressor, now supplied with plenty of amps, merrily kicked into life.

Given the compressor runs, where do I go now? Both fresh and see water pumps run. The reset switch on the control unit appears to be in its "in" position. I let a little gas out to confirm there's no sea water in there from a knackered exchanger.. Are there any checks I can do? Something must be sending a signal to something stopping it operating.

Cheers

 

[Whitelighter]

It could simple be a break in the wiring with a short somewhere - though Trevor is your man

 

[superheat6k]

This looks like simple electro mechanical controller. I assume you have tried pressing the reset button on the Penn dual pressure control, but the 'Pressure block' is still lit up. With this dual control this could simply be loss of gas leaving too low a pressure in the system.

I would take the cover off the dual pressure control and check with a screwdriver which pair of switch contacts are broken, but be careful because you likely have 240 volts in there. Your system will only have one pressure control device so this is where i would start my search for the problem.

Penn are very high quality control switches. Penn is a trade mark of Johnson Controls. If you can find the switch model number put it into google and you should find the part number. But you will need to disconnect the capillaries connecting it to the system otherwise the gas will leak out when you try to undo it. I found this model which will likely be yours if it has 1/4" connections on the base. If it has capillaries the model will be slightly different.

[h=1]P78mcb-9300 Penn Dual Pressure Controller D535587[/h]I note you do have 1/4" flare connections on both LP and HP side of the compressor, so re-charging etc is straightforward. For a system like this I would use R417A as a replacement for R22 (also known as Isceon MO59).

If you want to check the system pressure a simple Gauge manifold will tell you how much pressure you have. Using R22 on a 15oC day expect around 5 - 5.5 Bar standing pressure. Your LP switch is set to ~ 2.8 Bar.

This one is £12.59 from eBay

http://www.ebay.co.uk/itm/UK-SHIP-A...807200?hash=item461880d5a0:g:wkUAAOSwMKpUZYAP

 

[Mr Googler]

That great. I will order and see what the pressures are and take a look inside the controller.

I did notice than when I set it to cold as you previously said it takes less amps, only the fresh water circulation pump ran / lit up. I am also thinking a connection issue somewhere to as when off, all the lights on the front flicker a bit. Something's not happy but it looks pretty complex behind the panel to my untrained eye anyway!

Thanks again and will let you know the pressures.

 

[Mr Googler]

Had it confirmed today that I have no gas pressure.

I am finding out from condaria what the gas weight is for the system. The next hurdle is finding a supplier for replacement gas. My air con chap on the island doesn't have either r417 or r422 and is making some calls. I fear it could be tricky as most supply in 9.5kg bottles. Add shipping on that to Isle of Man and things are getting a little silly price wise for a regas!

Fancy a trip to the Isle of Man Trevor with a bottle under your arm

 

[superheat6k]

Had it confirmed today that I have no gas pressure.

I am finding out from condaria what the gas weight is for the system. The next hurdle is finding a supplier for replacement gas. My air con chap on the island doesn't have either r417 or r422 and is making some calls. I fear it could be tricky as most supply in 9.5kg bottles. Add shipping on that to Isle of Man and things are getting a little silly price wise for a regas!

Fancy a trip to the Isle of Man Trevor with a bottle under your arm

Much as I fancy a trip to see you three legged folk, I may have to pass presently.

If you can get the oil out of the compressor to allow POE68 Grade to be used instead then R407C will probably be OK, but there is likely no provision to drain the oil without removing the thing and tipping it out the suction connection. Have a look to see if there is a low point drain connection.

Other gases to consider are RS44 - R424A), or MO99 - R438A.

Your system will work on R134a but will lose about 30% of its capacity and would still require the oil changing to POE.

As to gas weight I would not overly concern yourself with this, simply charge refrigerant until the back (suction) pressure is steady at around 4 Bar (not R134a this would be around 2 bar), with a sweat line almost to the compressor on the suction pipe.

Although I disagree with it, R134a is available from Halfords in aerosol cans with oil included. R134a also requires a POE grade oil.

Looking at your photos my guess would be ~ 0.5 KG, so yes buying a 9.5 kg cylinder is an overkill. About 2 of the Halfords cans would likely sort your system out, but it does need the leak finding and then evacuating first.

Have you tried looking up Refrigeration repair firms in your yellow pages, as these will likely have at least one of these gases available for the fridges systems around your island.

R417A; R422D; R424A; R438A or with POE oil R407C or R134a (and reduced capacity).

As a footnote ALL existing systems are going to suffer major issues within 5-10 years as these HFCs - R134a / R407C / R410A, etc which replaced the prior HCFCs - R22 and CFCs R12 / R502 are themselves phased out. Our industry doesn't yet have satisfactory answers to these new rules and the impact will extend far far beyond keeping your cabin cool - refrigeration is a necessity for a modern civilised society yet the Politicos have decided they know better what is good for us all !

 

[Mr Googler]

Thanks Trevor. I think the leak is at the controller. One of the connections is gooey for want of a more technical term. A new danfoss controller is quite cheap but will nip the connection and see how we go. Thank you very much for all your help. I'm not native so just the 2 legs for me!!

 

[superheat6k]

Thanks Trevor. I think the leak is at the controller. One of the connections is gooey for want of a more technical term. A new danfoss controller is quite cheap but will nip the connection and see how we go. Thank you very much for all your help. I'm not native so just the 2 legs for me!!

Oil stains are the number one indication of a leak so you have likely found the problem. I trust you will get the problem resolved, but please contact me if you need further advice. I don't have any client contacts on IOM, but have some contacts in Liverpool and Belfast who might be able to help.