Strange TXV setup

[Gary]

Exactly - its a system that works (with dumb luck as you mentioned earlier) and there are little or no signs of why it works but wrongly. Everything looks right except the SH at the compressor and that is so delicate with charge.

There is no blockage as system was flushed with flushing liquid several times and tested for flow with a manometer system.

DesA points out that the bulb should be insulated (agreed) but it still wont make any difference as it never gets colder than the TXV and Mad Fridgie reckons the #4 could still provide enough flow at minimum turn down - could be onto something there.

Chef

Adding charge drops the SH (drops the suction line temp). So...

Insulate the bulb and add charge. The suction line temp will drop until the bulb temp is below the TXV temp and will thus regain its charge. If the SC is then excessive, there is a restriction.

A restriction could be an undersized or kinked liquid line, plugged TXV inlet screen, restrictive HX, etc..

[Chef]

Insulate the bulb and add charge. The suction line temp will drop until the bulb temp is below the TXV temp and will thus regain its charge.

Except if his Madness is right (usually is) the #4 is too big and works only with migration so if the bulb is allowed to regain control it might not be able to turn down enough.

So put in a smaller orifice and wont wont work properly till the bulb eventually gains control if it ever does.

Not sure I like that scheme of things

Chef

[Gary]

Except if his Madness is right (usually is) the #4 is too big and works only with migration so if the bulb is allowed to regain control it might not be able to turn down enough.

So put in a smaller orifice and wont wont work properly till the bulb eventually gains control if it ever does.

Not sure I like that scheme of things

Chef

Once the bulb is in control... if the TXV hunts, the orifice is oversized.