Heat Pump Woes....PROFESSIONAL ADVICE PLEASE?

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06-15-2008, 05:14 PM
Kevlar

Heat Pump Woes....PROFESSIONAL ADVICE PLEASE?

I've got a 13 year old home, we purchased in October of last year..

It's approx. 2100 SF... There's nothing remarkable about the house, just seems to be a very well built and VERY well insulated (tons of insulation in the attic) home...

The problem is the heat-pump, or what I think is a problem, so I'm asking for some advice...not knowing anything about heat pumps..

For starters, I keep a fresh/clean filter in the unit, and check it often..
I've learned that lesson already..

The heat pump is very quick to "freeze up" on us (the coils in the house) if I set the thermostat lower than 75 degrees...

Right now, it is almost 100 degrees outside (Waco, TX) and it is just happily humming along at it's 75 degree setting, cooling the house to 75 degrees, cycles on and off once in a while and does okay...at 75 only..

If I set it to 74, or any lower, the inside freezes up...and I've got to thaw it with the fan..even at 75 degrees, ice is beginning to form on the coils..

This occurs even at night. Our previous home (air conditioner equipped) I got used to sleeping in a cool house at 72 degrees or so..

Even at night, when it is 75-78 outside, I set this heat-pump less than 75 degrees, it freezes up..

It just seems like it's on the "verge" of freezing at all times..and I find that frustrating..

I've had it serviced twice, and the tech said everything is functioning as normal, and if anything, the a/c might be a little undersized for the home, and the blower on this particular model doesn't "push enough air" or something like that..but that's all he could tell me..

Is it too much to expect a heat-pump to cool the house down to 72 degrees at night on an 80 degree night when I want to?

Friday night, AFTER installing a fresh filter, I set it to 73 at 11:30 at night before I went to bed...only to be woken up to the sound of it humming as it was frozen again at 3:00 in the morning..

Is that asking too much?

Do you think my unit is undersized?

Do they lose efficiency over time and I just need to get a new one?

If so...how much should I expect to pay for a new unit inside and out..?

OPINIONS?
ADVICE?

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06-15-2008, 05:31 PM
hvaclover

Don't think u r undersized. Could be a loss of gas, indoor coil partially plugged with dirt.

If that's frost I am seeing on some of the indoor coil tubing it could be restricted internally.

Have you checked the surface on the condenser coil for buildup?

That's a common one on Ream products. They mfg louvred casing to go around the condenser but you can't see the build up unless you remove the
compressor compartment cover. If it's not clean it will look like carpeting.
06-15-2008, 06:47 PM
smittyii

what kind of filters are you using? this is an M style coil and requires alot of return air. i have tried using pleated filters with M coils. it doesn't work when it gets very hot. if you are running glass filters try taking the filter out for one night(don't do it more than one night though). if it still ices up i'd say dirty coil.
06-15-2008, 06:53 PM
Kevlar

I'm using the "Filtrete" brand???

Is there something better suited for my type of unit?

http://img.photobucket.com/albums/v3...971/Filter.jpg
06-15-2008, 06:58 PM
hvaclover

Quote:

Originally Posted by Kevlar

I'm using the "Filtrete" brand???

Is there something better suited for my type of unit?

http://img.photobucket.com/albums/v3...971/Filter.jpg

Theres the problem right there. Thefilter is so tight it won't pass enough air and you ice up.

Still would check for build up on out side unit.
06-15-2008, 07:02 PM
towney

Not sure of indoor fan cfm's, but would bet on dirty condenser. Rheem is not the easiest to put back together after cleaning so sometimes don't get cleaned well or as often as they should.
06-15-2008, 07:07 PM
Swampfox

Dirty condenser isnt going to cause a freeze-up

system is probably low on refrigerant, you need a service call

also, the first 3 feet of duct on that particular air handler is supposed to be the same size as the duct opening, looks like they made it to fit the size of the entire unit, I would have that corrected as well
06-15-2008, 07:08 PM
RyanHughes

Filtrete filters are too restrictive in general, so as Hvaclover said, that could be the source of your problem. Try a standard pleated filter (round edges, not 3M brand) or just the spun fiberglass (cheap blue) filters. If you remove the filter temporarily, does this stop the frosting? It could also be unrelated to the problem, so if it doesn't stop the frosting, you need to have a service tech (a competent one) come and check out the system.
06-15-2008, 07:25 PM
Airmechanical

*

swampy is correct;

those W style coils need to have ductwork installed properly or they will never work correctly!

they are the most unforgiving unit made when not duct is not installed properly!

could be other things, call a pro!

.
06-15-2008, 08:05 PM
hvaclover

Quote:

Originally Posted by Swampfox

Dirty condenser isnt going to cause a freeze-up

system is probably low on refrigerant, you need a service call

also, the first 3 feet of duct on that particular air handler is supposed to be the same size as the duct opening, looks like they made it to fit the size of the entire unit, I would have that corrected as well

We All know a dirty cond won't cause freeze up Swamp. I was just mentioning that cause it's so common with Ream.

Short of charge was also mentioned.

But I guarantee with a home that size a third horse power ain't gona push enough air thru that Filtrite filter.

A magnehelic would prove that.
06-15-2008, 09:40 PM
Swampfox

The filter isnt helping thats for sure

I think the airflow problems with those units had more to do with the blower positioning and design than the multiflex coils, the blower wheel is right at the outlet of the air handler, which is why the duct must be the size of the opening for static regain.

on other brands the blower is farther back and blows through the electric heater box
06-15-2008, 10:20 PM
hangfirew8

Quote:

Originally Posted by Kevlar

I've got a 13 year old home, we purchased in October of last year..

It's approx. 2100 SF... There's nothing remarkable about the house, just seems to be a very well built and VERY well insulated (tons of insulation in the attic) home...

Your situation sounds very similar to mine, an 11 y.o. Rheem heat pump in a modern house, had problems keeping up.

In my situation, the problem was several things:

1. The indoor coil was linted-up, and no one diagnosed that properly. As a result, heat transfer was poor, and the return line was low on pressure because it was low on returning heat.
2. The "professional" servicing it misdiagnosed the above as being "low on refrigerant" and put an extra couple of pounds of R-22 in it. This led to tripped breakers and a hard-start capacitor.
3. Outdoor unit coil full of grass clippings, despite several "annual service" done by "pros" who never noticed it or suggested cleaning it.

After getting a low restriction filter, I would call someone to come out to do a subcool/superheat check plus a pressure drop test. If you are told either one is not necessary, they know what they are doing, blah blah blah, thank them kindly, hang up, and keep calling.

Quote:

Originally Posted by Kevlar

Is it too much to expect a heat-pump to cool the house down to 72 degrees at night on an 80 degree night when I want to?

Even a somewhat undersized unit should be able to do that.

-HF