Sorry about any confusion, I use a Thermal Cap Check. This is a small hydraulic pump.
First I hook it up and pump oil through cap tube to guarantee it is open. Next a piece of lead wire slightly smaller than the inner bore of the cap tube is inserted in the tube. The pump is reattached and oil is pumped through the cap tube again.This clears the bore as any rectriction should be routed out by oil passing around the wire when it is detained by a restriction. Like most equipment user experiences may vary mine have been good.
Well I made one for about $20.00 It is about 80% effective. Bought a new grease gun and screwed an acces fitting where the hose used to go.
Piece of flared 1/4 inch tube. Braze tube into the other end. Fill grease gun with oil, tighten flare on to the grease gun and pump. Then I usually
put a flared filter dryer in the system just before the cap tube. Hope this helps.
If it's just a simple cap tube system, why spend the time and effort to attempt a cleaning? I could see it on a system that has tube soldered to suction lines, etc. but if you have to open the system anyway to "clean the tube", why not just replace it?
I agree, replace it. But on some idiot designs .. like a True GDM-49F where they decided to run the line set encapsulated in foam behind a cabinet that's permanent . . . I'd rather attempt a cleaning as opposed to running a line set kit. Accessibility on the evaps are horrible.
On a True GDM 49F just run the new cap tube inside the suction line. No need for a line set. Just cut the suction line at the compressor compartment then install a T fitting. Do the same up at the evaporator. Run your cap tube thru the T fitting up the suction line to the T fitting at the evaporator. Now weld everything up. You got a new cap tube inside the evaporator compartment