I turned on the geothermal unit yesterday to cool down the house as it was hot out finally, I guess we go straight to summer here in SD!  The house didn't cool down.  I checked the unit and it had the calming blinking green light saying everything is ok.  I opened the unit and found heavy frost on the Upper and lower sections of the Air Coil.  I checked the furnace filter and it was quite clean as I change them often.  Any thoughts before I call the service tech?

thanks

Ok, I'll start.  Homeowner here (standard disclaimer) with a geothermal also.

Just to check one more detail, the blower/fan was operating, correct?  I mean, you could feel air coming out of the vents around the house, but the air was warm?  room temperature? 

Was there any initial cold air from the system, or right away it wasn't producing cold air?

From your description, it sounds like the loop, compressors, and air coil are working correctly, but there is no/little air across the coil.  Either the fan is off, the dampers are closed, the filter is blocked, the coil is physically iced up so that no air can pass through, probably some other things, too.

More info?

You could also try putting it into heat and turning up the thermostat a few degrees above where it is.  Not to make the aux heat go on, but enough to see if the system will produce warm air.  It will/should also remove the ice/frost from the air coil.  Then turn it off.  Wait a little, start it up in cooling.  See if there is air movement across the coil and from the registers around the house.

Couple things to start..... Number 1... Is the fan running. There are a few things that will make our trouble shooting easier. Could u tell me the model number on your unit and the company that made it. As I was writing this reply member above responded and I agree. Loop, compressor, coil are operational. You can reverse cycle and heat. Question during this time was the front cover for the unit on? From time to time people like to show/inspect the unit and take off the covers. The fan will no longer grab air through the coil. Path of least resistance. Make sure the front cover is on extremely important.

Sorry it posted twice

Yes there is air moving through the system. It starts cooling initially and then ices up and loses cooling capacity. All of the house vents are open and air does move from them.

The front cover has been left on and the fan is running. We typically let the fan run all the time. It is going to cool off again so I will be flipping to heat this evening.

I will get the model number etc

It's a PO46 unit made by WaterFurnace for Geo Comfort when they were a Distributor for WF.

Take off the bottom cover. The first dip switch bar on the left has twelve positions. Please tell me whick numbers are on the right and which ones on the left. Second dip switch bar or middle one please do the same.

SW 1 - 12 positions
5,7,11 are in the on position

SW2 - 8 positions
1,4,5,6,7 are in the on position

SW3 - 5 positions
1,2,3,4,5 are in teh on position

Dip switches seem to be in the right locations. Where did you get your filters from is it electrostatic or pleaded?

Generally what you describe would be caused by a plugged filter or fan coil, undersized duct (return or supply), wrong fan speed or low refrigerant.
Have you had this unit in previous heating/cooling seasons? Were you able to see a jump in the heating bill this year?
j

They are pleated filters from lowes that I put together with aluminum tape to get the right filter size.

http://www.lowes.com/pd_162093-98-9888DC_0__?storeId=10151&Ntt=162093&UserSearch=162093&productId=3131017&N=0&catalogId=10051&langId=-1

If copying that to the browser doesn't work the item number is 162093 at Lowes. If this is the wrong thing to buy let me know where to buy the right stuff that would be great!

I have had this in previous seasons and I did think the heating bill was too high this winter but then thought maybe I was being a scrooge!

What would be the best way to clean a plugged fan coil?

Posted By geosd on 12 May 2011 08:43 AM
They are pleated filters from lowes that I put together with aluminum tape to get the right filter size.

If this is the wrong thing to buy let me know where to buy the right stuff that would be great!

What would be the best way to clean a plugged fan coil?

As long as the filters are not flexing and allowing air around (instead of through) the filter, what you are doing sounds ok to me.  Make sure the filters are changed when needed.

Your coil may, or may not, be plugged.  An inspection will tell.  Coil fins are very delicate.  I don't suggest you touch it in any way yourself.

Try comparing the heating degree days (HDD) for the last two heating seasons to see how they differ.

Also, if you are paying about $9/filter, you are looking at a 2.5 year payback on two* washable electrostatic filters.  You may need to clean them every 30-60 days though (takes some time, but worth it to me.)  http://www.theairfilterstore.com/dust-fighter-95  (just a happy customer)

* One to swap out while you clean the other filter.

well I did check the energy bill and year over year it looks like it's costing me about $2 per day more. Looking in through the filter area it does look like there is hair, dust, and other particles so I believe that to be the issue. I will see if I can get access to it tomorrow to clean those very delicate fins.

Finally a day of heat...I have placed a service call as the cleaning did not resolve the issue. Seeing as everyone called in with a broken ac unit it may be a week or so before anyone shows up.

Serviced this morning, gasket burned up and allowed a leak to occur so it was low on freon. Recharged.

Exactly what "gasket" burned up?

Bergy

Posted By Bergy on 05 Jun 2011 12:25 AM
Exactly what "gasket" burned up?

Bergy

Great question! My BS meter is goin nuts.
j

Gasket failure caused "freon" leak?

My left big toe!