Why is Central Air Freezing up?

Question

Central air unit is only 1 yr old, just had it charged and worked for 5 days. Today it was blowing warm air out of vents and the thick copper pipe leading to condenser outside of house was covered in ice. I shut it off. I read that it could be low charge or dirty filter, which filter? The filter on return vent is brand new, is there another filter in the air handler that I need to check? Really dont want to call service people out and get charged $88/hr if I can solve problem. Thanks

Guy came out on Sat, filled system with 325psi of nitrogen, waited for 20 minutes, meters did not move and could not find leak anywhere in lineset or in coil, where do you think its coming from?

Answer 1

I am going to answer your questions.

First, I would suggest that you do not try to diagnose the system yourself. Why? For your best interest. If the service tech was out on Sat. and you are experiencing the same problem, then call the company back up. They should have a Call Back Policy (A period of about 30 days) in which a customer is not charged for the same problem twice within that period. Now you should not touch the system because once someone else begins work on the system, then the ownership of the problem trensfers from the original company to you.

Is this the first summer of use? You said it was 1 yr. old.

Icing is causedf by either two factors:
1) Low of Refrigerant
2) Low airflow

Any technician who has had any formal training should know that he/she MUST make sure that the airflow is good BEFORE you check refrigerant pressures. Low airflow distort the head pressures on the gauges and make a system look as if it is low on refrigerant when in fact it is fine.

You also said that he injected the system with nitrogen. If there was a leak in your system, then after 20 minutes there would have been ample evidence to support a low refrigerant theory.

Things I would suggest you have the company check.

1) Evaporator Coil - You said filter was new, or not dirty. Fine, but the coil on the inside unit might be clogged with dirt. Easily fixed.
2) Blower assembly - Clogged or dirty fins could reduce airflow. Even check for damaged fins, or the motor itself might be failing causing low airflow.
3) Blocked return - Your air intake could be blocked. I have seen customers hang pictures over their return grille, back their sofas up against it, etc. This blocks the amount of air.
4) Lastly, have him or a qualified airflow diagnostician inspect the ductowork. It could be undersized. The AC system requires a specific minimum amount of air per ton. 400 cfm (cubic feet of air per minute) = 1 ton. So if you have a 3 ton system you need to have 1200cfm in order for the AC to cool correctly. My guess would be that being a new house, it has something to do with the ductwork.

For more information, or you can contact me with any additional questions that you might have, go to our website at www.howellsac.com

Answer 2

let me begin by saying the technician you had comitted the ultimate no no when it comes to checking for leaks. Yes he is right the unit leaking but he must find that leak with a leak detector solution, repair the leak and recharge with freon. I don't know where you live but the ac trade is really strong about not leaving units leaking. If your unit is new the filter will be clean and there is only one filter you need to chage. This must be fixed by a technician but call back the same company and tell them he didn't find or repair the leak and still leaking. Tell them you want a leak test, repair and re-charge with freon and that youre not going to pay again as this was suppose to be done the first time. Good luck

Answer 3

You have a Freon leak.

Simple having it refilled may work for a couple of days or so but the freeze up will re-occur.

You need to find out where the leak is occuring and have it repaired.

Any competent HVAC mechanic should be able to do this for you. You should call out the same people who charged your unit five days ago and have them fix it. They should cut you a discount on the refill.

P.S. The repair man should charge your system with helium and use an RGA (Residual Gas Analyzer) to detect the exact location of leak source. Simply watching for a PSIG drop when the system is charged with N2 is not enough. Its likely to be a very small leak, that's why you use He (Helium). He can migrate through the tinyest of opening and be detected.

Answer 4

some issues: a) out of your description, it truly is probable that the equipment has too little refrigerant in it. for this reason, there isn't adequate liquid interior the equipment to realize from the condenser to the evaporator (the coil interior your place). So, the refrigerant starts off to boil (evaporate) interior the pipe - inflicting it to seem to freeze. What this additionally ability is that not something is going on on the coil. b) AC contraptions paintings in 2 procedures - via direct refrigeration - you sense chilly air - and via de-humidification. Dry air feels cooler than humid air. So, a room at 40% humidity at 75F will sense lots extra effective than a room at 68F at 70% humidity. as a result, suitable 'sized' AC contraptions are continuously in elementary terms a splash of smaller than what somewhat the calculations would point out. AC contraptions, in basic terms as with heating contraptions, are at their maximum efficient whilst they are working flat-out. c) yet another available reason for coil freezing is letting the unit run too long with out cycling. exceptionally with a clogged condensate drain - yet that has a tendency to freeze the interior coil, not the lines outdoors. Get the equipment checked. clean the two contraptions of coils, substitute the filter out, and have the refrigerant point checked via a powerfuble technician. There must be a sight-glass someplace interior the equipment, and whilst the compressor is working you should verify no bubbles in any respect whether it truly is wisely charged. If there is not any sight-glass in place, get one put in. Any suited installation has one and you're entitled to it. In doing the installation they'll ought to evacuate the equipment, installation the glass, then recharge it suitable. and you'd recognize whilst they pass away that it truly is charged suitable. you additionally can do a leak attempt with soapy water alongside any areas of uncovered pipe - yet that isn't provide help to if there's a pinhole leak in a coil except you're very fortunate and discover it someplace you will see that it. The techs may additionally inject a dye interior the refrigerant which will coach any leaks ... it truly is that in the event that they are particular they did a suited value interior the commencing up. stable success with it.

Answer 5

your blower and fins are CLOGGED. i just had mine looked at... and first they said would and could be a leak , but when your blower is weak you will freeze up your CA unit on the pipes, so i say get your furnace cleaned and your blower cleaned as well as fins.. that's what I'm about to do. you also need to change filter in your furnace could be dirty, but I'm betting ya your blower is filthy like mine is... new home also from builder junk...FILTER YOU READ ABOUT IS IN YOUR FURNACE, CHECK IT, sorry about caps but important your filter is clean And changed every 30 days. again i say your furnace blower is clogged where the fins are. so warm air comes out. like ours is right now,also you may need to call a duct work place, they are the ones who do this kind of cleaning , its cheaper then heating and cooling guy for sure to...get your ducts cleaned while your at it.

Answer 6

You have your unit frozen solid. Turn on you heat for a couple of min. don't keep it on long enough for the blower to get going. Repeat a couple of times every 15 min. or so.