Suction temp

[Temprite]

Hello all.

Does any one have any idea of what the highest suction line temps that manufacturers rate for sealed units before they start to give trouble with overheating? (In particular Hermitique.)

Reason I ask this is because I know of a system serving a hotel that has an extra long pipe run and I noticed that the suction line is not very cool due to the length of it.Also the liquid line is strapped to the suction line also increasing the superheat.

I did once check the suction line temp and I think it was about 23 degrees c. The compressor itself is always quite hot to touch also.My belief is that eventually the excessive superheat will eventually damage the compressor.I have raised my concerns about this to another fridgy but he thinks I am worrying needlesly.Apart from this the system works perfectly.

I have thought about maybe setting up some kind of desuperheating set up on it.

Thanks all.

[chemi-cool]

Hi Temprite,

You can add an injection valve between the liquid and the suction lines to cool the compressor if it gets too hot. Does it?

Chemi :)

[Abe]

Hi Temprite,

You can add an injection valve between the liquid and the suction lines to cool the compressor if it gets too hot. Does it?

Chemi :)


Chemi, you mean on scroll compressors dont you?? Not on hermetics,

[chillin out]

Hi Temprite,

I would insulate the suction pipe and also make sure you are not going to over condense with a very long liquid line.
If by the time liquid line reaches tev it is quite cold you could open the tev up a touch or move the senser bulb further down the suction to increase work load and cool comp down. ...(just a thought, too tired to think about it properly so don`t nobody shout at me)

You could either stick a comp cooling fan on or make the cond fan spin the other way to draw fresh air over comp then through cond if comp is getting very hot.
:) :)

[Temprite]

Hi Temprite,

I would insulate the suction pipe and also make sure you are not going to over condense with a very long liquid line.
If by the time liquid line reaches tev it is quite cold you could open the tev up a touch or move the senser bulb further down the suction to increase work load and cool comp down. ..
:) :)

Thanks for the comments all.

Chillin
System runs temprite systems, no TX valves low side float.
I have thought about insulating suction line and pulling liquid line away from it that would certainly help.

I spoke to the wholesale company that deals in hermitique and they said that the suction temp was to high, but they couldn't give me a value of which it should be kept under.

Aiyub
Why no desuperheating on hermetics?

[Peter_1]

What is a Temprite system?
What brand of compressors?

[Deejey]

Peter_1 a temprite is a beer dispensing unit. You could almost call it a shell & tube evaporator..where the liquid refrigerant in in the shell ans the beer is in the coils. The liquid level is controlled by a low side float and the evap pressure maintained by a 750 valve.

Temprite..On a long suction run you may be getting oil return problems and also excessive pressure drop High superheats will also cause high discharge temperatures and combine these factors and your compression ratio will increase. this will reduce the life of the compressor. High superheats also mean a decrease in the density of the refrigerant meaning that there is less refrigerant pumped per stroke of the compressor. This increases running time and electrical consumption. I have done a lot of temprite work and you can email me if you wish. I notice you are also in Australia..I am in Tasmania

[Temprite]

Peter

Compressor is a Hermitique(4 or 5 hp I think.)and Deejay has already explained a temprite.

Deejay
Compressor origonally was a belt driven type as most of these old pub systems were.compressor cooling wasnt a big factor.The old belt compressor has been changed and a hermetic put in its place it has a remote condenser.System runs really well just has a very high suction temp.(Any suggestions?)

Just to get off the topic.
Is it true that in Launceston somewhere on a pub there is a system running with a PVC suction line? (Being from Tassie I thought you might know of this.

Regards.

[Deejey]

I dont know about using PVC for suction line but I have students from launceston tomorrow so will ask them....but I doubt it....the pvc would deteriorate to quick
Anyway...what size was the compressor that came off & what size is the hermetic..it sounds to me as if the hermetic isnt big enough for the capacity required...therefore high suction pressures...also is there an oil trap on the compressor discharge and also a surge tank on the suction line?? also what beer temperatures are you getting and what setting is the 750 valve...

[Deejey]

I would suggest measuring the pressure at the 750 valve....and then the pressure at the compressor and see how much pressure drop your getting....is the suction line exposed to sun or any other heat source that could increase the superheat.....how much superheat are you getting...I think you said the temp was 23C at the compressor....which means you would be getting around 21K superheat which is way way to much.....

[Peter_1]

..;Peter_1 a temprite is a beer dispensing unit....
Where can i find some info of this?
Chemi, you remember I once send you a description long time ago (a scan of a Refr. book) of an ancient beer cooler system? Well, it seems not that ancient at all and it's still used in AUS.
Here in Belgium - the land of the beers - we always use an ice bank with a double coil in it: a coil for the beer and a coil for the refrigerant.

[Temprite]

Where can i find some info of this?
Chemi, you remember I once send you a description long time ago (a scan of a Refr. book) of an ancient beer cooler system? Well, it seems not that ancient at all and it's still used in AUS.
Here in Belgium - the land of the beers - we always use an ice bank with a double coil in it: a coil for the beer and a coil for the refrigerant.

Peter read that post about the ancient beer cooler.

That is indeed a temprite system and yes they are ancient its just that the pubs havent got off their backsides to change them yet.

Still a fair amount of pubs using them.When they get around to replacing them they usually go to a glycol system.When you have several temprites on one system they have pretty large gas charge.

We use ice banks here too,but I think glycol is becoming the popular choice.

One thing I have noticed is that some temprites just dont operate properly on anything other than r12 unless they are designed for r22 then their usually ok.

When I chose my user name I thought temprite was a fairly australian refrigeration term, as did 750 valve I would say.

[Temprite]

Deejay.

System has an oil seperator and a surge tank.

I havent checked the setting on the 750 valve but it is probably around 0 deg c.

They never complain about the beer in there.(unless there is a power failure.) I think last time I checked it was about 2 deg c.

The suction line and liquid line are strapped together, if I seperated these and insulated suction line this would make a difference.if it was still a belt driven unit it wouldnt be a problem.

Ever had a temprite that wont operate properly on anything other than r12? Try them on any other gas than r 12 and they have no recovery.Usually the drop ins are ok but not always.

[Deejey]

Temprite...I would indeed seperate the lines and insulate the suction....it should have a surge tank fitted to prevent short cycling whenever a beer is pulled..it would help to insulate that too.

[Temprite]

Deejay.

System has an oil seperator and a surge tank.

Deejay system definitely has a surge tank fitted but not insulated.

[Peter_1]

.....as did 750 valve I would say.
Ohhhhh...i thought it was that thing under his nose in his Avatar LOL
BTW, next dump question , what is a 750 valve?

Regarding the Temprite system again. These system are much smaller then the systems we use here with glycol. You always need a big space to install the ice bank and the Temprite system seems much more compact.
You don't need an agitating mixer, no glycol, ...
How do they manage the oil return in these systems? I once read it was done with some sort of a cotton cloth which was floating on the vaporising liquid.

[Deejey]

Peter_1
Temprite systems have an oil seperator which includes a high side float fitted to the discharge. when oil gets into a temprite it does not return and affects the beer temperature.
A 750 valve works the same as a evaporator pressure regulator. You maintain the saturation temperature in the temprite by adjusting the pressure with the 750 valve the same as you maintain the sat temp in an FDC by adjusting the EPR.

[Temprite]

Peter
What more could I say.....

Sometimes temprite will get oil binding,due to oil taking up space of liquid refrigerant.Doesnt happen much if oil seperator is working.

You can fix this by shutting hand valves and removing temprite and charge into suction line.By turning upside down when you do this the oil goes back into the sump.

I am trying to get hold of an old manual on temprites (might take some time).If i can I will post on this thread.

[Deejey]

I think I have an old kelvinator temprite manual somewhere...will look tomorrow...havent seen it for ages..but have got it somewhere....