not sure what's wrong

[richard_ln]

Most of my work has been new construction and very little service tech so forgive me if this is too simple. My ex-wife called me a few days ago and said her heat pump wasn't cooling. She said someone replaced the compressor, which made it much better, but it's still not cooling like it should. So I thought that unless I want to give her even more of my hard earned money, I better load up the truck and head over.

Here's what I found. It's a 3 ton 10 seer HEIL split system heat pump with a TXV. New copeland recip compressor and new dual cap. Coils are clean, filter is clean. I put the guages on and that's when I got a little confused.

outside air temp - 81 inside air temp = 78 Outdoor humidity: ~70%

Suc Pressure - 64 Suc temp - 80

Liq Pressure - 200 Liq temp - 87

Condenser TD - 13 Evaporator TD - 14

My handy Trane charging chart shows it being slightly overcharged.... but shouldn't be enough to give me such a low TD across the evap. Rather than just start fiddling with the charge I thought I might want to actually try to figure out what's wrong with it.

The only other thing out of the ordinary is the condenser fan was replaced with one that's 75 rpm faster. It calls for a 1075 rpm and has a 1150. In my brief experience I believe that won't have a big effect.

any ideas?

[Noon-Air]

Without laying on of hands, my best guess would be to first pump down the system, put in a bi-flow filter dryer, blow out the lines with N2 to clear out any debris left from the old compressor, then clean the TXV screen, seal the system back up, pull a 400micron vacuum, and re-charge with virgin refrigerant. Start by weighing in the factory condenser charge, then balance with SH/SC

Let us know how it works out.

[richard_ln]

Will do. Thanks for your help.

Also, I forgot to mention that I heard a slight gurgling noise in the liquid line, before the TXV. To me, that suggests an undercharge because there's not a solid column of refrigerant at the TXV. That was part of my confusion... a chart reading an overcharge but symptoms (gurgling) indicating undercharge.

[Noon-Air]

Will do. Thanks for your help.

Also, I forgot to mention that I heard a slight gurgling noise in the liquid line, before the TXV. To me, that suggests an undercharge because there's not a solid column of refrigerant at the TXV. That was part of my confusion... a chart reading an overcharge but symptoms (gurgling) indicating undercharge.

You may have air and nons in the system that are giving you false readings.

[Gary]

My first assumption would be that your low on gas. Your running over 40 degrees SH & your subcooling is not bad but I would suspect a little low for that system so nothing to me sounds like an overcharge. I would add a little gas & see if it brings your SH in line & raises your TD. If that doesn't work then I would follow Noon-Air's advice but I always try the easiest way first. If it is low on gas then I would check the indoor coil because I've had countless of those Heil coil leaks.

[KJPRO]

This is your problem HOW???? She's an EX for a reason!

More of your money??? Are you required to maintain HER equipment or living conditions???

How long is the lineset and where is its location? Have you checked for proper indoor fan speed? The system is NOT overcharged or you would have a higher Subcooling reading.

[Stormin Mormon]

Very possible you have a load of air in the system.

I'm learning to make good use of my IR thermometer. A hot filter dryer (after the condensor) means that the condensor needs cleaning. The guys on the list groan, roll their eyes, and call me a hack. But I've learned that even a clean looking condensor can be way below efficiency.

[Zyp]

I'm thinking your TXV isn't opening enough to fill the coil completely with refrigerant, hence a low TD across the evaporator with a high superheat.... [low performance.]

All other signs seem normal, except that since the evaporator isn't getting enough refrigerant, I'd see a low head pressure because the system isn't picking up enough heat......

Thinking about Noon-air's recommendation, I'd likely go his route but install a new TXV while I'm there cleaning / checking the screen before the valve.

[richard_ln]

That makes perfect sense. When I go back I'll do that.

[KJPRO]

Parrot

Not always...

Just stating FACTS!

Many OTHER problems can cause this...

[Gary]

I think you're trying to cut a piece of grass with a chain saw. All the guys have brought up good points but there's nothing in your numbers that negates the possibility of a low charge which would take all of five minutes to try. If that doesn't work then go get the chain saw.

[Stormin Mormon]

We can charge more money for the complicated stuff.

Still, it's as you say. Try the simple stuff, first. Especially when it's not a paid job (wink wink).

[welcome to new jersey]

Sorry I did not fallow all that transpired however in regard to thermal expansion valve position of thermal sensor bulb it is a standard for sensor to be position on lines 5/8 OD at 12 clock as line increase in size the bulb will be position to the side as example 21/8" line will have bulb position around

4-5 clock position, however in air condition work it could be some place around 3 clock or even higher it depend on velocity of refrigerant moving through the line. Note if air is moving over the bulb you should always consider put some insulation over it. Tony

[richard_ln]

Ok. I didn't get back when i thought I would but I made time over the long weekend. non-cons was the problem. I evacuated it, put in clean new R22 and it worked like a champ. The TXV was clean. Thanks for all your help.

[Stormin Mormon]

Enlisted are the backbone of the service. Non-cons are just as essential as officers.

That said, I've had plenty of dealings with non cons. I can think of two or more cases, without hardly trying. It's amazing, what evac, pump out the air, and recharge. What that does for a system.

Thank you for letting us know.

[KJPRO]

Glad to hear your problem is solved. :-)

[Noon-Air]

Ok. I didn't get back when i thought I would but I made time over the long weekend. non-cons was the problem. I evacuated it, put in clean new R22 and it worked like a champ. The TXV was clean. Thanks for all your help.

Your welcome