Frigoboat not getting cold

[Donheist]

Any ideas? I have a brand new evaporator connected to a Madrid compressor. I have power to compressor and it is making noise (I would say “working” but the plate isn’t cooling.) The first bit of the evaporator ie the inbound “pipe” seems to be cold but the plate itself isn’t. I have bypassed the thermostat with a simple loop to rule that out but the thermostat is also brand new. I have cleaned and remade all the electrical connections.
What’s next?

 

[ChromeDome]

Sufficient gas pressure in the circuit?

 

[Concerto]

Have you tightened the pipework to break the seals to allow the gas to flow?

Did you break the seal on one pipe but not the other and the gas cannot circulate?

Has the gas has escaped?

All the above are possible. Having fitted a Dometic fridge unit to my cool box this year I made sure I followed the pipe connection instructions exactly. The one thing you must not do is disconnect the pipes as all the gas will be lost and the units will need to be returned for refilling and sealing again.

 

[Donheist]

I wondered about gas. I did follow the instructions exactly. And yet….

maybe I need a pro to come and look - if I need more gas they can add it. I’m loathe to mess with the connections for the reason you say…

 

[Concerto]

I wondered about gas. I did follow the instructions exactly. And yet….

maybe I need a pro to come and look - if I need more gas they can add it. I’m loathe to mess with the connections for the reason you say…

Might be worth adding a little more tightness on the pipe connections before you call for assistance.

 

[Donheist]

Might be worth adding a little more tightness on the pipe connections before you call for assistance.

Good call. Tomorrow I will try and remake them. Shit or bust!

 

[Donheist]

Good call. Tomorrow I will try and remake them. Shit or bust!

epilogue:remade coolant connections and got better but still indifferent fridge performance. But today halfway to Malta suddenly we have frosting. All seems well! Not sure if that is a bit of engine vibration dislodging something or an alternator-boosted battery voltage? I will do some multimeter work if performance drops after we arrive…

 

[tudorsailor]

Do you have an inline filter drier in the line for the coolant?

TS

 

[Donheist]

Do you have an inline filter drier in the line for the coolant?

TS

I don’t think so - just the evaporator connected straight to the compressor with the proprietary presealed connections.
But I did notice that one of the crimps I made yesterday was not best so I’ve remade them. Fingers crossed…

 

[Donheist]

Electrics all good but still not cold - how hard is it to top up refrigerant? Do I get some r134a and a kit from Amazon? Or find a pro?

 

[clyst]

........ get a pro in .......... it seems as if it needs topping up but beware over filling is as bad as lacking coolant.

 

[Daverw]

If you’ve remade any of the flares you will need to vac out before recharging, this removes the moisture by pulling low vacuum and boiling it off, without doing this properly very small ice crystal will form and block tubes and stop it working again. Vac pumps can be not too much but then you need hoses and then gas, get someone to come and do it.

 

[superheat6k]

Ditto Daverw reply - was the evaporator evacuated, if not the system is possibly jammed with air, which is a crap refrigerant as it gets as far as the condenser and then prevents anything from flowing. If the system has already been opened then a full degas, evacuation and recharge with fresh gas is required.

Once the gas is out I would undertake a proper leak test just to be sure there are no leaks.

But the kit to do this as well as the knowledge if what you are paying a professional for.

He will also want to know what gas you are using.

There will be a real shock coming in the next couple of years when R134a ceases to be realistically available, but there are some alternatives to consider.

 

[Dogone]

It sounds like low gas to me. You need oil and additive free for these units if adding it. Not easy to find. Also pressure gauges and leak detector as if you have low gas you probably have a leak. Unlikely to have air in the plate as it factory pressurised.

 

[superheat6k]

It sounds like low gas to me. You need oil and additive free for these units if adding it. Not easy to find. Also pressure gauges and leak detector as if you have low gas you probably have a leak. Unlikely to have air in the plate as it factory pressurised.

The OP mentions in reply #7 he remade the cooling connections. If this means he disconnected the fridge lines then air in the system is a very likely possibility.