friend_of_frozen
09-19-2006, 01:32 AM
Hello all,
Glad to find this forum. I enjoy tinkering with cars and computers but no nothing of HVAC.
My friend's house had a new split-system heat pump installed this past spring. I know it has an Amana TempAssure II model RHE30C2A unit outside. In my ignorance I did not realize there is a separate model number for the inside section - everything I know about HVAC, I've learned from a couple of hours reading this forum.
I am pretty darn sure the air handler inside is not an Amana though; I've looked at it several times and I don't recall seeing the name on the front. It _looks_ a lot like the Amana handlers with the evaporator stuff at the bottom (e.g. the ARUF series) and just like the Amana, hers has the black plastic rectangular access panel on top. If necessary to this discussion I can check more on what model the AH is next time I'm over there.
Problem is icing. The first time it happened, I learned she had not changed her air filters since the unit was installed - maybe 4 months? And when I checked them they were completely clogged up - she has three cats and doesn't vacuum the carpet often. Also, they were the cheapest filters, the ones with flimsy blue fiber stuff.
From reading here, I understand that air flow is the number one cause of icing.
But after changing the filters, about a month ago, the icing is now continuous. System will run fine for a few hours, then gradually the airflow sinks - a sheet of paper no longer sticks to the return grill, supply outflow is reduced - and sure enough, turn it off, remove the main filter behind the air handler, look up inside drywall and the evaporator coil is a solid block of ice. Icing also apparent on copper lines inside outside unit.
Let unit defrost, turn on again, few hours and it's solid ice.
A side note: even ignorant putzes like us knew this thing wasn't installed right, as it was happening. It's a tri-level house and the contractor (major house renovation) advised we should have two HVAC returns, with the secondary one downstairs - the main return and the air handler behind it is on the top floor. (Apparently in our area in her type house, two returns are code.) HVAC installer claimed he couldn't run a return from the lower level, so he put a small 12inchx12inch return in the ceiling of the master bedroom, just inside the door - which puts it about 6 feet away from the main return in the top-floor hallway outside the bedroom! Also, while the registers on the top and bottom floors seem to blow a fair amount of air, there's only a trickle felt out of the middle floor registers.
So this thing has airflow problems out the wazoo to begin with.
Still, the AC functioned nominally for several months, until the first freezeup.
Three questions for now:
1) The coil is an inverted-V open type, visible up inside the box formed by the back of the closet holding the air handler and the return grill opening on the top-floor hall. What is the best way to attempt to clean it? The only thing I can think of is to squirm a vacuum cleaner hand attachment up there and try to run it across as much of the inverted V grill that I can. Any other suggestions?
2) I replaced the low-budget filters with the anti-allergen kind available at any big box home store; I got the highest rated one for stopping dander, etc. Given the marginal airflow of this overall system, do these hypoallergenic super-duper filters significantly impede airflow? (They don't appear clogged at all, not like the solid layer of material coating the original filters.)
3) Because if #2 isn't the answer, then I'm concerned that the initial icing somehow damaged the evaporator coil/air handler system.
My plan is to try cleaning the evaporator coil as best I can, on the theory that the very dirty cheapo filters were letting too much crap get to the coil. If that does not solve the problem, I will try replacing the filters with cheapos again in the hope of increasing airflow, assuming the "premium" filters do in fact block flow enough to initiate icing.
Beyond that I'm at a loss and will have to point her to professional help - NOT the bozos that installed the thing. (They also installed the tstat wiring wrong so no power got to it, contractor's electrician rewired it and had to do something to the outside wiring as well. Oh, and they left one entire duct pipe unattached to its outlet in the attic, and ran off without properly installing 90 percent of the registers: covers left off, adjustment vanes with no adjustment screws or simply missing altogether, etc.)
I don't want to hurt anyone's livelihood, but then again I don't think a homeowner should have to pay for an expensive service call just to clean off coils - if there _are_ any tips to the latter, maybe it's OK to share them here? As well as general airflow advice re the filters?
Thank you!
Glad to find this forum. I enjoy tinkering with cars and computers but no nothing of HVAC.
My friend's house had a new split-system heat pump installed this past spring. I know it has an Amana TempAssure II model RHE30C2A unit outside. In my ignorance I did not realize there is a separate model number for the inside section - everything I know about HVAC, I've learned from a couple of hours reading this forum.
I am pretty darn sure the air handler inside is not an Amana though; I've looked at it several times and I don't recall seeing the name on the front. It _looks_ a lot like the Amana handlers with the evaporator stuff at the bottom (e.g. the ARUF series) and just like the Amana, hers has the black plastic rectangular access panel on top. If necessary to this discussion I can check more on what model the AH is next time I'm over there.
Problem is icing. The first time it happened, I learned she had not changed her air filters since the unit was installed - maybe 4 months? And when I checked them they were completely clogged up - she has three cats and doesn't vacuum the carpet often. Also, they were the cheapest filters, the ones with flimsy blue fiber stuff.
From reading here, I understand that air flow is the number one cause of icing.
But after changing the filters, about a month ago, the icing is now continuous. System will run fine for a few hours, then gradually the airflow sinks - a sheet of paper no longer sticks to the return grill, supply outflow is reduced - and sure enough, turn it off, remove the main filter behind the air handler, look up inside drywall and the evaporator coil is a solid block of ice. Icing also apparent on copper lines inside outside unit.
Let unit defrost, turn on again, few hours and it's solid ice.
A side note: even ignorant putzes like us knew this thing wasn't installed right, as it was happening. It's a tri-level house and the contractor (major house renovation) advised we should have two HVAC returns, with the secondary one downstairs - the main return and the air handler behind it is on the top floor. (Apparently in our area in her type house, two returns are code.) HVAC installer claimed he couldn't run a return from the lower level, so he put a small 12inchx12inch return in the ceiling of the master bedroom, just inside the door - which puts it about 6 feet away from the main return in the top-floor hallway outside the bedroom! Also, while the registers on the top and bottom floors seem to blow a fair amount of air, there's only a trickle felt out of the middle floor registers.
So this thing has airflow problems out the wazoo to begin with.
Still, the AC functioned nominally for several months, until the first freezeup.
Three questions for now:
1) The coil is an inverted-V open type, visible up inside the box formed by the back of the closet holding the air handler and the return grill opening on the top-floor hall. What is the best way to attempt to clean it? The only thing I can think of is to squirm a vacuum cleaner hand attachment up there and try to run it across as much of the inverted V grill that I can. Any other suggestions?
2) I replaced the low-budget filters with the anti-allergen kind available at any big box home store; I got the highest rated one for stopping dander, etc. Given the marginal airflow of this overall system, do these hypoallergenic super-duper filters significantly impede airflow? (They don't appear clogged at all, not like the solid layer of material coating the original filters.)
3) Because if #2 isn't the answer, then I'm concerned that the initial icing somehow damaged the evaporator coil/air handler system.
My plan is to try cleaning the evaporator coil as best I can, on the theory that the very dirty cheapo filters were letting too much crap get to the coil. If that does not solve the problem, I will try replacing the filters with cheapos again in the hope of increasing airflow, assuming the "premium" filters do in fact block flow enough to initiate icing.
Beyond that I'm at a loss and will have to point her to professional help - NOT the bozos that installed the thing. (They also installed the tstat wiring wrong so no power got to it, contractor's electrician rewired it and had to do something to the outside wiring as well. Oh, and they left one entire duct pipe unattached to its outlet in the attic, and ran off without properly installing 90 percent of the registers: covers left off, adjustment vanes with no adjustment screws or simply missing altogether, etc.)
I don't want to hurt anyone's livelihood, but then again I don't think a homeowner should have to pay for an expensive service call just to clean off coils - if there _are_ any tips to the latter, maybe it's OK to share them here? As well as general airflow advice re the filters?
Thank you!