Heating Issue with a Heat pump in heat mode.

[coolinman]

Throw a sightglass and pressure tap in the liquid line by the condensing unit. The liquid (3/8") service valve is giving low side pressure in heating so you can't tell liquid pressure. I use a electronic sight glass to see if the liquid line is full. Bottom line is there is not enough refrigerant or a restriction in the indoor unit or on the way back to the outdoor unit. You may want to check and see if there is a drier someplace that you havent seen that may be plugged. Suction pressure in heat should have a saturation around 20 degrees below entering outdoor temp.

[socotech]

I had a similar problem a few years back. Several techs before me tried everything and still could not correct the problem. I put my gauges on and immediately could see there was a restriction. Guys before me pulled the piston and checked it and it appeared fine. I pulled the piston and it wasn't plugged but the orifice looked too small for the size piston. I pulled out my handy drill index to check the piston and sure enough the orifice was too small. It was the correct piston but somehow copper had deposited itself in the piston orifice. I used my drill and chipped out the copper and put the piston back in and it worked great after that.
You really need to measure the piston orifice to make sure copper hasn't reduced the orifice size through some type of electrolysis. You'll need a drill index that measures orifice sizes.

Where can I get this drill index. That would save me a lot of calling around trying to figure out correct size. I have ran into this problem too (a couple of times).

[Brent Ridley]

At 68 degrees outdoor ambient...you can charge by superheat and subcooling. Charge the system correctly using this method then see where you're at in heat mode. At least then you can rule out the system being undercharged. You have a mismatched system therefore weighing in the charge may not be correct.

[martinxxxxxx]

The drill index is (if I am not being a numpty) determined by measuring the piston then checking against a drill index for the correct drill number and trying that drill in the orifice.
I might be corrected on this
Martin

[air1]

[URL=http://www.amazon.com/Drill-Master-Titanium-Nitride-Numbered/dp/B006ZBBW00/ref=sr_1_10?s=hi&ie=UTF8&qid=1356719200&sr=1-10&keywords=numbered+drill+bits[/URL]

The drill bits are numbered drill bit sizes. They come in handy for verifying orifice size and cleaning out orifices. You can get very tiny sizes to clean pilot burner orifices.

[air1]

Doing a little research online I learned that copper electroplating occurs in a refrigeration system when acids are present. It makes sense because the job that I found copper plating on the piston had the compressor replaced and the piston was the original piston. The copper from the tubing dissolves and is suspended in the oil and usually deposited on steel surfaces in the compressor such as bearings and pistons. The results are that the bearings or pistons will bind causing the compressor to fail.
Using a numbered drill set you can verify the orifice size. If the drill bit won't fit then you might have copper plating. You should be able to see the plating because the copper is a different color.
But, if you have copper plating, you probably have acid in the system. Do an acid check and clean-up as necessary.

[martinxxxxxx]

Numbered Drills

The drill bits are numbered drill bit sizes. They come in handy for verifying orifice size and cleaning out orifices. You can get very tiny sizes to clean pilot burner orifices.

Your link did not work, so I have taken the liberty of fixing it.

It is essntially the same as what I said in my post to a simular set of numbered drills , but mine are available in this side of the pond.

Great minds think alike

[air1]

Your link did not work, so I have taken the liberty of fixing it.

It is essntially the same as what I said in my post to a simular set of numbered drills , but mine are available in this side of the pond.

Great minds think alike

Thanks for fixing the link.

[ryan1088]

I had a similar problem a few years back. Several techs before me tried everything and still could not correct the problem. I put my gauges on and immediately could see there was a restriction. Guys before me pulled the piston and checked it and it appeared fine. I pulled the piston and it wasn't plugged but the orifice looked too small for the size piston. I pulled out my handy drill index to check the piston and sure enough the orifice was too small. It was the correct piston but somehow copper had deposited itself in the piston orifice. I used my drill and chipped out the copper and put the piston back in and it worked great after that.
You really need to measure the piston orifice to make sure copper hasn't reduced the orifice size through some type of electrolysis. You'll need a drill index that measures orifice sizes.

That's very interesting, I wouldn't have considered that.....

[Firebird A/C]

toyo066....what ended up being the problem????