[jims$]

At the moment, my heat pump compressor does not continue running to cool my home properly. I can start the system up and it will run for approximately 1 hour properly. While running, the condenser fan is pushing out warm air and the lines are respectively hot and cold. After around one hour, I believe that the compressor is not running because the condenser fan air is no longer pushing warm air and the lines are the same temperature. When this happens, the small copper line at the A-coil is frosty on the exterior.

Two HVAC companies have looked at the unit. Company A said it is a TXV and wants to replace the A-Coil and TXV. Company B said the unit does not have TXV's and they think the Puron lines might have debris in them that are clogging the Puron pistons. They want to thoroughly clean them out at the cost of $1500. Does this sound right?

 

[roughneck]

Your unit uses either a piston or TXV metering device. Which one do you have? It's one or the other, for the indoor unit.

 

[jims$]

According to company B, I have Pistons.

 

[supers05]

Do you have any model numbers and who makes it? Indoor/outdoor unit. Is the indoor unit just an air handler or a furnace too?

If you can open the panel where the lineset goes into the indoor unit, take a picture and post it here, well know for certain.

At 1500, you're about half way to a new unit. How old is this heat pump?

Cheers!

 

[user_12345a]

Where does the frost form?

Doubt it's a txv issue if it's upstream of the txv.

A restriction will show up with refrigerant line pressures/temperatures.

You'll see frost starting from where the restriction is.

It makes zero sense to replace an evap coil because the metering device has a problem.

 

[jims$]

Thanks for your responses. Info as follows:

- Bryant brand.
- Heat pump with electric back-up.
- Air handler model: FB4BNF060.
- Condensing unit model: 3601E03255.
- Price to clean out Puron line set: $1525 and they won't guarantee that they can get all of the impurities out. May have to do this cleaning more than once.
- Company B quoted a Lennox Gold replacement at $15,515 and $13,425 if I pay cash (which I would). This is a 5-ton heat pump with everything inside and out included. 4700 square foot home.
- With existing units in the 13 year old range, I am wondering if I should just go ahead and replace the whole system or have the Puron line set cleaning done.
- The attached photos show the Piston? area and in the other photo I am pointing at the copper line that frosts up after the AC has been running for approx one hour.

 

[BayouRunner]

Technician could pump that unit down. Clean/check that piston, install a drier and pull a vacuum in no time. I'm not saying it would be bad to upgrade. But that does not seem to be that hard of a repair.

 

[user_12345a]

Present model number appears to indicate a 3 ton - is it? or maybe that's a serial number.

Can't upsize by 2 tons without re-doing the ducts.

---------------------
The pricing as well as solutions proposed are totally absurd.

The icing up of the coil could be from low airflow, low charge or a restriction at the metering device.

If the restriction was upstream of the metering device the frost or condensation would start there.

This can be fixed, a question of getting it properly diagnosed. 13 years isn't old, you should get 20+ out of equipment.

 

[jims$]

Bayourunner: Thanks for the reply. The $1500 repair would be to remove the Puron, install a new dryer, run something through the line set to clean it, braze everything back together and fill the system with new Puron. I have no idea if that is a difficult, time-consuming repair or not.

User_12345a: Thanks for the reply. I double checked the model numbers and you are correct. I mistakenly provided the serial # for the condensing unit. The model number is 652AJ060-B. The air handler unit in my previous post is the correct model number.

The icing only develops on that smaller copper line just before the piston. The unit ran for about an hour each time before kicking off. One time, I think it just kicked off the compressor and the second time it kicked off the entire outside unit. When it kicked something off during both tests, I noticed frost where my finger is pointing. I am not sure which way the Puron flows in and out of the A coil. That small copper line that is frosting up is a few inches from the piston. I am wondering if this means that the A coil piston is clogging or partially clogging and that is why it is frosting up in that location?

Company B tested the the charge and it is fine.

What is an average appropriate amount for them to clean out the line set and install new Puron? This is what they want to charge $1500 for.

What is an average appropriate price to pay for an entire new unit. I would definitely obtain another couple quotes prior to handing over $13K. I live in Indiana.

 

[user_12345a]

I don't know about pricing, just that 1500 sounds insane.

can't see why they can't pump the unit down, disconnect liquid line, blow nitrogen through liquid line, put a new piston.

doubt it would take more than 2 to 3 hours, don't know how on earth they could justify charging that money even charging something like 200 an hour.

-----------------
The refrigerant flows into the coil through the small copper line - since the frost is starting before that, does sound like there's a blockage or something.

 

[jims$]

User: They talked like the new Puron was a lot of the expense. Is it real expensive to purge the Puron and install new?

 

[user_12345a]

i don't know about pricing of refrigerant since i don't work in the field.

they can keep the refrigerant, pump it into the outdoor unit with the compressor (there are valves that can be closed) and do the repair.

they only have to put new refrigerant if it's been contaminated with air/moisture and maybe with a restriction it has been been. wonder what the restriction is, could even be the contents of a failing filter drier in the unit, dessicant escaping from it and plugging the piston.

if there's an internal drier that should be changed, for that the "puron" needs to be removed.

i don't think r410 is that expensive.

1500 is total theft.

 

[bfletcher7]

they only have to put new refrigerant if it's been contaminated with air/moisture and maybe with a restriction it has been been.

Can't they check for non-condensables by measuring the temperature of the recovery tank and comparing to a PT chart?

 

[supers05]

Puron is a trademark, period. It references r410A. This is what you have. It's much cheaper then r22, and can be reused when handled right. User is right that it can be pumped down, but a recover unit still has to be used since the compressor is unlikely too pull a vacuum. (30min for the average system)

You have a piston, not a txv for the indoor unit. While the piston is easy to replace and cheap too, I'm not sure if that's the problem. Oddly, the manual I found mentions that you MUST have a TXV on the indoor unit and a piston on the outdoor unit. Either I found the wrong manual or the original installer never installed the TXV. Granted it will still work fine at a lower efficiency, but the charge will be different.

If the piston is actually partially plugged, reversing the system sometimes can clear such blockades. (switch to heat then back to cool repeating after 15 min of running or so) The filter drier should catch the crud. (if it's not defective) Make sure that you're not activating the aux heat. (maybe turn off the element breakers for this procedure)

http://dms.hvacpartners.com/docs/1009/Public/04/PDS652A.24.1.pdf

Cheers!

PS. If you have a temperature probe/ ir gun, get some temperature readings for us:
1) supply air at a register and/or just after the coil
2) return air
3) liquid line (smaller line that your finger was on) near the outdoor unit
4) liquid line just before the indoor unit
5) immediately after the piston. (just before or on the small distribution tubes
6) suction line (bigger line)
7) outdoor air

 

[beenthere]

Is there anything in/on/part of the line just before the area that freezes up? If so, can you post a pic of it.

Next time it freezes up, pull the cover and see if its also frozen up at the piston area.

Sounds like they plan on using RX11 or similar to clean out the line set. Before something like that is attempted. The system should be pumped back to teh condenser, or recovered, and the piston holder opened up, and checked for a restricted screen/strainer. hate to see you pay all that money when the strainer can be cleaned in a few minutes, and put back in. Then the line set and coil vacuumed and the charge released back into the system.

 

[user_12345a]

Can't they check for non-condensables by measuring the temperature of the recovery tank and comparing to a PT chart?

wouldn't know what impact that would have, presumably throw it off?

 

[jims$]

Additional info and comments:

- I tried going from heating to cooling twice (heat, cool, heat, cool). I still have no consistent cooling after letting the ac run for about 1.5 hours after these tests.

- One of the attached photos shows labels A and B that I placed on the smaller copper line to help describe the issue. A gets frosty after about five minutes and this front travels inside the cabinet past the piston and frost forms on all of the tiny copper lines that come from the piston area and feed the A-coil. The B side is not nearly as cold as the A side. There is a small device between the A and B areas. It has a gray top and is wrapped in a ball of pipe insulation. It has a small square design on the gray top. I have no idea what this is. There is a separate photo of that device. Really small (probably 1/8" diameter) copper lines run from this device and there are a couple of these small lines.

- One photo shows how the frost builds up on the A area, the piston area and the very small copper lines running from the piston area. This happens within 5 minutes of turning on the ac.

- One photos shows the frost totally gone from the A-coil and this is approx 8 minutes after turning on the ac. So, it totally frosts up in five minutes and the frost goes away after 8 minutes. The compressor still was running after about 15 minutes, but was not running after 1.5 hours. It sounds like it is running, but cooler air is blowing from the condensing unit and the big and little copper lines are not very cold at the condensing unit.

- I do not have any type of thermometer to to help provide actual temps.

Thank you for your previous responses.

 

[user_12345a]

it does look like u have a txv in the new pics, looks like it's insulated/covered and i see the equalizer line.

 

[jims$]

User: I will provide a little better photo of that device for you. It is attached.

 

[beenthere]

You have a TXV. And there is a good chance its powerhead has lost some to most of its charge. The good news is it looks like it has a removable powerhead. Which means the powerhead can easily be replaced.

Still have to pump the charge back to teh outdoor unit, and may have to recover some of the refrigerant if its a long line set. But much cheaper then a new system, or 1500 bucks to clean a line that doesn't need cleaning.