Re: Temprite and oil return.
Given the huge amount of replies I thought I'd ask another question. Is there any reason you couldnt use LP control to open and close a solenoid to control temp of suction?
Re: Temprite and oil return.
Quote:
Originally Posted by
Filby
Hi
Im just putting together a 'homebrew' portable chilling system. Ive got a brand new spec'd 1.5kw condensing unit with a liquid receiver on it and a Lovelocks 2 pour temprite. Im going to stack the temrite on top of the condensing unit and have a 2 tap font on top of that. I'm just wondering how this system deals with oil return to the compressor or if I even have to worry about it. Also, when charging the system how do you know that the actual temprite is flooded to the right level?
Cheers
Fil
I did answer yesterday but between interruptions maybe I didn’t press the “Submit reply” button.
If you respect suggested suction diameters and common practice in piping layout and follow the temprite manufacturer’s recommendations you should not worry for oil return.
But you should not let the hot air from the condenser flow around the temprite.
Quote:
Given the huge amount of replies I thought I'd ask another question. Is there any reason you couldnt use LP control to open and close a solenoid to control temp of suction?
There are two main reasons not to do it which are a mix of reliability and human psychology.
Should the pressure switch fail your compressor will most probably fail too.
If the user wants to set the temperature for any reason he will tamper with a less understood device several times and this will increase the chances of failure.
LPs installed on the unit subject to vibration fail at a higher rate.
If you set the LP at low thermal load the temperature will not be right at high thermal load. If set at high thermal load the unit will stop before the temprite reaches its temperature at low thermal load because you reach your set pressure before the temperature sabilizes.
If the refrigerant used is not an azeotrope, glide affects your temperature-pressure.
With a thermostat you have a device that the user understands better and an LP as protection device should the thermostat fail. The probability of both thermostat and LP failing simultaneously is very low if you have a warning light that the system is acting on pressure and not temperature.
Even better with a themometer-thermostat so you also have a good diagnostic tool.
Re: Temprite and oil return.
Quote:
Originally Posted by
Filby
Hi
Im just putting together a 'homebrew' portable chilling system. Ive got a brand new spec'd 1.5kw condensing unit with a liquid receiver on it and a Lovelocks 2 pour temprite. Im going to stack the temrite on top of the condensing unit and have a 2 tap font on top of that. I'm just wondering how this system deals with oil return to the compressor or if I even have to worry about it. Also, when charging the system how do you know that the actual temprite is flooded to the right level?
Cheers
Fil
OK - the system doesn't deal with oil return, I have pumped down and up ended many temprites over the years that have been full of oil and lost their ability to transfer heat. Make sure you have an oil separator on the system. If it disappears the only way it will return is if the float cartridge fails and the temprite overfills with liquid and washes oil back down the suction line, even then its not always possible as although the oil is miscible with the refrigerant as it is sitting stagnant in the temprite it has a tendency to separate out from the liquid and fall to the bottom of the temprite.
The best way to charge the system is to keep a load on the temprite (run water through it with the 750 Valve set at about 5 degrees SST to ensure it doesn't freeze), the temprite will fill to its operating level based on the low side float inside (non adjustable). The run some beer through and back the 750 valve off to achieve beer temp.
Quote:
Originally Posted by
Filby
Given the huge amount of replies I thought I'd ask another question. Is there any reason you couldnt use LP control to open and close a solenoid to control temp of suction?
No because there is a low side float inside, the temprite will hold more refrigerant than your receiver and cannot be pumped down with the system you are proposing - that is normal with temprite systems though. You could use a suction solenoid but you will see temp swings.
Just fit n LP cycling the unit, cut it in at the same pressure the 750 valve is set to, cut it out just above zero. If it short cycles then kiss cold beer goodbye :D
