home AC/heat experts need help

rfuerst911sc · 07-17-2012, 04:35 PM

We have a room addition on our home that is heated/cooled by a 12,000 btu PTAC unit. It recently started acting up and we've decided to replace it. I have found a internet seller that has competitive prices and a variety of brands. They sell Gree , Friedrich , Amana , LG and GE. Does anyone have experience with these brands ? Is one better than the other ? They all seem to be within $75.00 of each other in cost. So I'm looking for any advice on these units. I'm not looking to change the style of unit I am going to go with another PTAC unit. Any advice is appreciated. Thanks

nota · 07-17-2012, 06:02 PM

acting how ?

ice is caused by blocked drains and dirty coils
fans need a cleaning too

controls a bath in tv tuner cleaner can be a cheep fix

nota · 07-17-2012, 06:17 PM

LG is korea

no idea on the others BUT I would ask

btw I rate japan>Taiwan>S Korea >china > other far eastern > india

gshase · 07-17-2012, 07:01 PM

My buddy owns an electric motor repair shop and he loves the LG unit he put in his 1500 sf addition.

look 171 · 07-17-2012, 07:57 PM

American STandard make by Trane would be my choice. I or my HVAC men spec that out all the time. haven't any issue since. The trick is parts availability in the future. You save now, but you will pay later.

rfuerst911sc · 07-18-2012, 01:59 AM

Quote:

Originally Posted by nota

acting how ?

ice is caused by blocked drains and dirty coils
fans need a cleaning too

controls a bath in tv tuner cleaner can be a cheep fix

It is icing up when on AC. I have cleaned the filter which wasn't that dirty and have vacumned the coils. I can see through the cooling fins so I don't believe they are blocked. I had a AC dude come out and he stated these do not have charge/service ports so if it's low on refrigerant no way to add unless you attempt to cut the linsa and add service ports. There are no drains on these units, they take the excess moisture and sling it onto the exhaust fan which vaporizes it but I did have standing water in the tray when I noticed it wasn't cooling well.

red-beard · red-beard's Garage

You might consider a mini-split, so that you can put the evaporator in a different, more central part of the room. Hitachi makes the most efficient versions which are now in the 25+ SEER ratings.

nota · 06:28 AM

coil cleaning spray foam will get ice problems most times
water will form on the cold side and needs to flow to the hot side
so check the inside water path for blockage
or drill drain holes to let the water drip out

but ice means the unit is cooling it just has air/water flow problems
and good cleaning should fix it

make sure the unit is mounted so the water will flow correctly
a small tilt can allow the water to pool in the wrong area

billybek · billybek's Garage

Icing can be caused by low charge. After a long run time, the ice will cover a good chunk of the evaporators surface.

If it is low on charge, you could recover the refrigerant (R-22?) using temporary line access ports. Before doing that though look for signs of oil anywhere on the unit. Some leaks will be easy to fix/find and some will drive you crazy. If find and repair a leak, remove the temporary access ports and install permanent access on high and low.

The Trane PTAC units were pretty reliable but I remember some of the commercial mechanics at work replacing control boards on them at a few hotels in the city. I think they were not heat pumps, but cooling units with strip heat.

I really like the mini splits as well. Much quieter in the room with only the fan noise from the evap fan.

rfuerst911sc · 07-18-2012, 01:16 PM

Quote:

Originally Posted by nota

coil cleaning spray foam will get ice problems most times
water will form on the cold side and needs to flow to the hot side
so check the inside water path for blockage
or drill drain holes to let the water drip out

but ice means the unit is cooling it just has air/water flow problems
and good cleaning should fix it

make sure the unit is mounted so the water will flow correctly
a small tilt can allow the water to pool in the wrong area

Where can I purchase this coil cleaning foam ? I want to try this. Thanks

krystar · 07-18-2012, 01:27 PM

available at most hardware stores. just ask for condensor coil cleaner

rick-l · 07-18-2012, 01:40 PM

Is the reason these form ice when they are low on charge is that the capillary tube (is that what this unit has?) doesn't flow enough liquid and the pressure in the evaporator goes down lowering the temperature?

Part of the coil has the latent heat of vaporization and the other is just sensible heat? The part with the liquid ices over?

billybek · billybek's Garage

Quote:

Originally Posted by rick-l

Is the reason these form ice when they are low on charge is that the capillary tube (is that what this unit has?) doesn't flow enough liquid and the pressure in the evaporator goes down lowering the temperature?

Part of the coil has the latent heat of vaporization and the other is just sensible heat? The part with the liquid ices over?

Close enough.
When low on charge, the back (suction) pressure drops. This results in a lower (below freezing) saturated refrigerant temperature. The ice on the coil starts right after the metering device (tx valve or cap tube). Once that part of the coil is frozen, the ice slowly starts to spread through the rest of the coil.

Good first line of defense is to make sure the filters and coils are clean. Second make sure the fan is running to speed and is not loaded with dirt/dust on a forward curved fan. Third make sure vents are not blocked on the discharge air side. Mind you if you have a tx valve system and see continual flash gas in the sight glass (not just at start up or high load conditions) you are most likely short of gas.

WaltherHa · 07-18-2012, 07:01 PM

American STandard make by Trane would be my choice.

rfuerst911sc · 07-19-2012, 01:31 AM

I stopped at Home Depot last night and bought two cans of foaming coil condensor cleaner. This weekend I'm going to slide the PTAC unit out of the mounting sleeve so I can take outside to do a real good cleaning. Hopefully that will solve the problem. Appreciate the advice from all that have chimed in.

rfuerst911sc · 07-22-2012, 03:06 AM

Yesterday I slid the unit out of the mounting sleeve and carried it outside to the deck so I could do a good cleaning. Did see evidence of some oil staining under the evap so my guess is that is where the refrigerant leak is. I went ahead and did a thorough cleaning and slid her back into place. Plugged it in and ran it for 30 minutes no cooling at all so she's done. I'll be buying a replacement unit. Thanks everyone for all the suggestions.

rfuerst911sc · 07-23-2012, 06:48 AM

After much internet searches and several phone calls I purchased a new Amana PTAC unit. Made in the US and is the same model as what I have now the only difference it uses R410 vs. the R22. I purchased from Ingrams Water and Air in Paducah Ky. they were very nice to deal with and had a great price- $671.00 delivered to my door. Not a bad price for 12,000 btu's of AC with a 3.5kw heat strip and it just slides into place with 6 screws, plug it in and good to go. Hope to have it by the end of the week.