fujitsu split a/c icing up

[bwana]

I had a fujitsu halcyon installed and it's exhibiting odd behavior. I find the fins on the part in the house growing a layer of ice on them. (I guess that's the evaporator?) Condensation that freezes obviously. The installer says it's because the unit is too powerful and that the airflow over the fins is too slow. Even when I try runing the unit on high, it still ices up. And you've got to love all that water running down your wall when the ice melts after you turn it off. The installer has tried recharging the system to no avail and now he is telling me this is a NORMAL thing?!

any recommendationson how to proceed? is this a known phenomenon? I never had it happen with those a/c units you put in a window.

[Termite]

If the installer is telling you that it is normal then he is full of crap. It is definitely not normal.

[Simomatra]

If the installer is telling you that it is normal then he is full of crap. It is definitely not normal.

The evaporator should not be iceing up it woulds appear that you have a restriction somewhere. First place to try is your evaporator filters. Lift the front cover slide them out and check them for a blockage.

I don't think that your installer is a full bottle on the system

Give us a post back with what you find

[bitingmidge]

What they say .

Firstly, you are getting condensation which is then icing up, so... http://www.wunderground.com/cgi-bin/...weekday=Monday ...is the temperature set below the dew point- 62° these last few days? If you are trying to drop the temperature below the dew point in humid conditions, well that's what happens!

Crank up the thermostat to something like 74° (23°C) and see if the problem goes away.

(Shudder.... why don't you have your heater on, it's only barely getting up to the temperature we aircondition DOWN to anyway!??):confused:

I've had LOTS of similar troubles, mostly in rental apartments where people leave doors and windows open in times of high humidity, then try to condition the world, by dropping the temperature as low as possible!

Now as a matter of course we have all thermostat ranges in the units we sell, set to within one and a bit degrees of 23°C but leave the knobs/led's showing the full range. When people come in a crank the temp down to the min (15°C - 60F) on the dial, it drops to 22 and we don't have any icing up or condensation problems any more!

I've had similar problems in retail tenancies with larger ducted units, and also in cars which used to have - (maybe still do) heater elements to stop them icing up - how counter productive is that?

Before you do anything else, close the windows and turn the temperature UP.

Just a layman's guess.

Cheers,

P

[bwana]

last weekend it hit 80deg F in New England so I thought I'd start up the a/c. It was just installed last summer and barely used. At that time the installer had to come back FIVE times - first he checked for leaks and reconnected everything. came back - used a fancy gadget that can 'sniff' freon or whatever he used to charge the system - R410 i seem to recall . Fixed that and topped me off. said he found a small leak at the flare joint. problem still there. checked the pipes for blockage and found none. checked the evaporator- brand new and not a speck of dust.

by then fall had arrived and it was too cool outside to do any more testing.so here i am again, 10 months later.

Interestingly, the ice only forms on the top part of the fins- the front vertical part and the bottom side are frost free. the temp on the unit is set to no lower than 70 deg F, outside temp is 70 to 85 deg F, Rel Hum about 60-80% these days although i am sure it will rise higher.Dew point has been below 60 deg F. Of course the windows are closed, I have to PAY my electric bill.

this fujitsu halcyon has an auto setting, cool, fan, and dry setting. the icing only occurs on the auto or the cool settings. usu after about 4-6 hours. i seem to recall he specified a 1 1/2 ton unit - the living room is southern exposure and 400 sq feet but has two large double door sized openings that cannot close (no doors) that lead to a foyer and a family room. Effectively it is 1000 sq feet. the house is old (mediocre insulation).

I dont want to sound like a smart alec but I've read alot and it seems this is a fairly common problem that can be resolved by downsizing the condenser or upsizing the evaporator. Other solutions I've read about include:
Low pressure cut out CO=40psi and CI=80psi, anti restart timer 3-5 minuites, High pressure cut out manual reset, crank-case heater if a recipricating compressor, expansion valve AND sight glass (see below), head pressure controller.

How much of this do I need? I called Fujitsu but I think I get more help by talking to God.

[kiwigeo]

At that time the installer had to come back FIVE times - first he checked for leaks and reconnected everything. came back - used a fancy gadget that can 'sniff' freon or whatever he used to charge the system - R410 i seem to recall . Fixed that and topped me off. said he found a small leak at the flare joint. problem still there.

Bwana,

Not an expert but in my work I spend alot of time working inside portable air conditioned/pressurised lab units on offshore oil rigs. We have alot of problems with air cons doing exactly what your unit is doing and 9 times out of ten the problem is a leak or low refrigerant in the unit.

Your techie found a leak but did he fix it? If he had to top the unit up with refrigerant then IMO the leak needs fixing if it hasnt been fixed already.

Cheers Martin

[Ashore]

First if the inside and outside units are a matched pair, ie they came as a unit then they should be matched and there is no need to downsizie the condenser or upsize the evaporator.
The unit should have as a normal safety standard a low press and high pressure cut out built in , the low are usually self re-setting , the High press cut out's are manual reset.
Crankcase heaters are fitted if outside temps drop below freezing.

Your problem could be wrong sige evap unit , Unlikely
Lack of air flow over the evap; fan intake partially blocked; or dirty filters , both ef these can be inspected by you. From what you have said however again unlikely
Water in the systen , if air with water vapor gets into the system , and you don't need much, the water particles will freeze at the 'TX' or expansion valve and give much the same result, can be checked by opening up the evap unit, and as the gas enters the unit is the expansion valve if this has a block of ice built up on the outside remove by melting with a hot wet cloth and then if the evap fins stop icing for a few hours water is your problem.
Finally and most likely a lack of gas Would fit the symptoms you describe , espically as only the top half of the fins are icing up, check condensor unit, by removing the covers, there should be a sight glass fitted , maybe under a rubber cap, check that there is a full flow of liquid passing through and not gas or mostly bubbles when running.


If you want to check the joints for leaks make a thick soap and water solution and put over the joints with a paint brush if you see bubbles its a leak.

Rgds

[bwana]

well, the schematics and service manual show that the expansion valve is on the outdoor unit-so i checked it-no ice. so, i guess i have to call that installer guy- hate to do it cause i know this problem just makes him feel inadequate. one thing i did notice though-the instructions to the installer indicate that the system should be charged from the liquid phase-not the gas phase and i dont think that was done.

[Ashore]

well, the schematics and service manual show that the expansion valve is on the outdoor unit-so i checked it-no ice. so, i guess i have to call that installer guy- hate to do it cause i know this problem just makes him feel inadequate. one thing i did notice though-the instructions to the installer indicate that the system should be charged from the liquid phase-not the gas phase and i dont think that was done.

Did you find check the sight glass ?
Did you check for an obstruction to the fan intake ?

It is quicker to charge on the liquid phase , but easier in my experiance to suck on the gas phase
Most if not all gas bottles used for recharging have two fittings at the top one for gas and the second is a tube inside the bottle to the bottom for liquid.

Rgds

[Termite]

Makes me glad I bought a Daikin.

[Simomatra]

Hi Bwana

As a matter of interest has your installer done the new R410a traing requirement.

Below is some info for you

R-410A is incompatable with R-22. Adding Puron to an R-22 system will contaminate the referigerant and ruin the system. As with R-11, R-12 and R-22 and the other CFC based referigerants, it is illegal to vent R-410A, also known as "blowing the charge."
Unlike the CFC refrigerants, you cannot vapor charge R-410A. If you vapor charge, the ingredients will not mix properly and can contaminate the system. If the system in undercharged, there is a way to bring it up to specs. Invert the bottle for liquid discharge. Zero your scale. With the system running, slightly open the vapor port on your guage manifold, keeping it almost closed. What is happening is the drops of liquid referigerant are being vaporized before it hits the compressor intake. Using your temperature/pressure charts, add referigerant to lower the liquid line temperature and recover to raise it.
The pressures on a running Puron system are much higher than an R-22 system. R-410A head pressures can go as high as 500 lbf/in³, while suction would average around 140 lbf/in³.
The oil Puron uses absorbs moisture. All Puron systems come with a liquid line filter dryer. This must be installed. Not installing a filter dryer will shorten compressor life and void the warranty. It will also fail inspection. Achieving a deep vacuum is more critical. 450 micrometres is the minimum vacuum required.
When brazing in a Puron system, you must run nitrogen through the system. Brazing without nitrogen will shorten compressor life.

[Simomatra]

Hi Bwana

forgot to say that if it was recharged incorrectly then this could be the problem

[bwana]

@ashore
no, there is no sight glass in this system. the fan intake on the evaporator runs the length of the unit and the filter is pristine.

@simomatra
holy icicles! now i'll really sound like a smart a$$. thank you for the info. the current version of the fujitsu halcyon uses 410 refrigerant. is this what puron is ? I dont know what pressure numbers he was getting when he did the install-i thought he knew what he was doing. how badly am i hurt if he used the wrong refrigerant? would a 410 based system even work if r22 or r14 was used?

[Ashore]

Mate i'de go with sam, he looks like he's found the problem,
Rgds

[Simomatra]

Bwana

I think you need to realy identify with the installer what he has done.

Maybe you should investigate a second opinion from another tradesperson who can physically test your unit and identify what is exactly causing your problem.

Puron is atrade name for R410a