Back to basics

[charliewhite]

Hi There

This may be a bit basic for some of you out there but any info would be much appreciated!

If you have a standard setup with evaporator & Ex equalised tev what different symptoms are there from a blocked tev or a system thats very short of gas.

Thanks

Signed

New to this game

[Gary]

Naming a problem and figuring out the symptoms is backwards. The system tells you its symptoms, and you figure out the problem.

[charliewhite]

Thanks for the reply

Here are the symptoms.

When the compressor starts up the head pressure initially rises but then like the suction pressure it drops till it trips out on low pressure.There is no hissing at the tev & no evidence of a leak.The sight glass tells me nothing( only thing I can say is that there are no bubbles, but could that be because its very low on gas )

Thanks

[charliewhite]

Thanks Marc

I'll give it a go

Thanks

[herefishy]

Originally posted by charliewhite
( only thing I can say is that there are no bubbles, but could that be because its very low on gas )

I interpret this as, "The sightglass is either full or empty (of liquid)". Of course the TEV not being noisy would tend to indicate a full head of liquid in the liquid line, but considering charliewhite's self proclaimed lack of experience, one would speculate whether he is familiar with the volume or nature of the noise that we refer to in regard to TEV operation. Particularly in consideration that he is not sure whether the sightglass is entirely empty or full (of liquid).

[frank]

what firm are you working for charlie?

[Gary]

The pressure, and therefore the temperature, drops at the point of restriction. So the question is, following the liquid line from the condenser, at what point does it get cold?

[Gonzalo]

Usually the system that is very short of refrigerant will have a lot of flash gas feeding the valve and the evaporator will freeze up on the first rows of pipes.Low suction pressure,high superheat.

On a block TEV the liquid line is full,the valve present a ice build up in is body due to the blockcage.