Over Condesing under condensing

[jaymax]

Hello all

Can anyone help, I'm still new to all this and some of you veterans my find this a bit of a silly question ? Basically can a blocked condenser cause under condensing which in turn may cause a liquid line sight glass to flash ? I know a sight glass should have a full column of liquid but if the condenser is under condensing surely it is not producing this ? or do I need to rethink all the things I have learned about refrigeration. Basically can some one explain over condensing, under condensing or point me in the direction of a good book that may explain it

[taz24]

Hello all

Can anyone help, I'm still new to all this and some of you veterans my find this a bit of a silly question ? Basically can a blocked condenser cause under condensing which in turn may cause a liquid line sight glass to flash ? I know a sight glass should have a full column of liquid but if the condenser is under condensing surely it is not producing this ? or do I need to rethink all the things I have learned about refrigeration. Basically can some one explain over condensing, under condensing or point me in the direction of a good book that may explain it

By Under condensing I assume you mean not enough condensing.

In which case the answer is yes.

A blocked condenser will reduce the efficiency, so the hot refrigerant vapour will not all turn to liquid and therefor it will bubble down the liquid line.

If the cond is clean and efficient then the vapour will all change to liquid and then subcool a few degrees, resulting in a full liquid line and no bubbles.

It is hard to over condense for the most part because you can only cool down to ambient temps. If it is in the middle of winter and the condenser is on the roof with the wind and rain blowing through it you can over condense and the result would be very subcooled liquid and a drop in head pressure.


taz.

[mad fridgie]

Under condensing, as TAZ stated,
Over condensing, really does not occur, what this normally means is that your condensing pressure (thus liquid pressure) is to low to drive the correct amount of liquid through the expansion device, causing a low suction pressure. In some cases liquid can pool in the condensor (ome times known as "held up", giving the effect that the system is short of gas. In other words the reciever is not holding the liquid, so liquid and vapor enter the liquid line. Sub-cooling as and where that happens thats another thread!

[jaymax]

Thank you, that realy makes sense