Any HVAC experts on this forum?

[TurboFiat124]

I have a Trane Weathertron III (?) that was installed in 1985 and this thing seems to require allot of maintenance for some reason. About 3 or 4 times a year the inside coil freezes over because the filter get's clogged. Yes I know your supposed to replace these things once a month whether they need it or not but sometimes I just forget to change it.

I cannot use anything but those thin fiberglass filters in which the size is hard to find at that. The actual size of the coil measures 15" X 19" so I typically just buy a 14X20 filter and break the cardboard corners down so it covers the entire coil. I don't think there is a such a thing as an 15X19 filter since filters don't seen to come in odd number sizes.

I've tried those 3M filtrete filters and those 1/2" thick "cut to size" washable fiberglass mesh filters from Lowe's. Otherwise the coil freezes over due to poor air flow. First of all is this normal that these type of filters would restrict the air flow that much to freeze the coil over? I have a fairly new air handler fan. Could the inside coil itself be restricted and need to be vacuumed or blown off with compressed air?

But here is my main question. I am totally baffled.

Sunday when I got home from work it was in the 30s outside. I went down to my den and noticed no air coming from the vents. HMMM, that's weird, that only happens in the summer when the A/C is switched on. The weird thing was, the house was not that cold. I have a 8500 BTU propane heater in my enclosed carpet and I suppose there was enough heat transfer to keep the rest of the house warm. That is good to know because whenever my heat pump has issues in the winter, I usually switch the ceiling heat on the 3 remaining rooms that the system still works and it actually works quite well despite the fact that heat rises. And also if the power goes out. I have a 7500 watt backup generator which can power just about everything in my house except for my heat pump which is an energy hog.

I went into the basement and noticed the 1/2" pipe exiting the unit had some ice buildup around it. I pulled the panel off to look at the filter. The coil was frozen over but this time the filter was not that dirty. Usually when the coil freezes over, the filter is totally blinded over. But this only happens in the summer when the inside coil is on the "high side" and is cold.

This is a first for me. If the heat-pump is on heat mode, shouldn't the inside coil be on the low side and"hot"? How could the inside coil possibly freeze over in heat mode?

I threw the breakers to the heat-pump, flipped on my ceiling heat breakers and let the coil thaw over nice. Next morning, I installed a new filter, flipped the breakers back on and ever since then the inside coil has yet to freeze over.

Today I was looking around at my outside unit and noticed that sections of the insulation that goes around the 1/2" pipe from the outside unit was gone. Well last time I looked at it back in the summer, the insulated was rotten and a bit crusty looking but was still in tact. The same 1/2" pipe that that had a buildup of ice around it on the inside. So I replaced it with some water pipe insulation and some zip ties. Any chance the deteriorated insulation had anything to do with this?

I can see how the inside coil would freeze up due to poor air flow on A/C mode but how is this possible on "heat" mode since the inside coil should be hot.

Thanks.

 

[zzyzzx]

If a fiberglass filter is restricting the flow to the point where the coil freezes, up, you have some sort of other issue. Like some other flow restriction (dirty coil, dirty vents (hint: check the return lines, with particular attention to the spots close the the vent) or maybe you have low refrigerant.

 

[rubberchicken]

Only a minor comment- I have had good luck with the 3M Filtrete filters- I usually get the purple ones that have the 1500 ( ? ) rating. I replace them about 4 times a year. I did replace a circa 1991 Ruud heat pump unit that was very efficient for its time, with a similar sized Carrier unit about 2012, and my electric bills went down about 30%. I do not recall the exact SEER rating from old to new, but it was a jump of about 6.

 

[bioburner]

Your way past due for a new system Heat pump tech has progressed as much as vehicles. Your utility may have some decent rebates. Lot of states are trying to get the utility companies to update and lower power use

 

[sciphi]

My wager would be dirty inside coil or low refrigerant level. Try the easy fix of cleaning the inside and outside coils with A/C coil cleaner spray. Rinse it out well with water, distilled if your water is liquid rock. It's about $6 a can at the box stores. After that, getting a reputable HVAC person out to check the refrigerant level might be advisable.

There's not much that can clog one of those super-cheap fiberglass filters. If it's a fancier pleated filter, those come in several different restrictiveness levels. Finding the most basic ones possible that flow the best would be better.

Any chance of posting pictures?

 

[zzyzzx]

Originally Posted By: rubberchicken
I have had good luck with the 3M Filtrete filters-


A filter that is way more restrictive is only going to make the OP's problem worse. They need less air flow restriction. If I were them I would only use the cheap fiberglass filters.

 

[Tdbo]

I'd start with having refrigerant level checked and having the system tested for leaks.

 

[zzyzzx]

One thing you can do is just turn the fan on ans put your hand by a vent to see if you can feel about how hard the air flow is going.

 

[zzyzzx]

Originally Posted By: bioburner
Your way past due for a new system.


I am surprised that one that old still works.

 

[Nick1994]

Quote:
I have a Trane Weathertron III (?) that was installed in 1985 and this thing seems to require allot of maintenance for some reason.


Are you serious?

It's over 30 years old!

 

[JHZR2]

Originally Posted By: Tdbo
I'd start with having refrigerant level checked and having the system tested for leaks.


+1. That shoukd be remedied by increasing pressure a bit. Of course its illegal if theres a leak.

 

[rubberchicken]

Originally Posted By: zzyzzx
Originally Posted By: rubberchicken
I have had good luck with the 3M Filtrete filters-


A filter that is way more restrictive is only going to make the OP's problem worse. They need less air flow restriction. If I were them I would only use the cheap fiberglass filters.


Your are making the assumption that the 3M Filters are more restrictive. I hooked up a manometer on my intake side and measured them, and found that the high end 3M filters had about the same restriction as a cheapy fiberglass filter. I did not test the midlevel 3M filters, only the high end ones.

That said- now I have a manometer and a combustion gas analyzer that I do not need

They are up on eBay now. The main purpose I bought the tools was to try to tune a Bosch tankless water heater, which turned out to be a POS. It finally gave out and I replaced it with a Bosch Integra 500 which has run perfectly.

 

[TurboFiat124]

WOW! allot of replies!

One reason I've yet to replace this system is it still works.

That was when they built stuff to last. My father replaced his 25+ year old GE heat pump a few years ago when the compressor failed a second time with a Rheem unit. Boy did he get reemed! He said about three years after having the Rheem system installed, the compressor went bad and was not covered under warranty. Then he said something (a deer perhaps?) bumped the filter on outside unit which broke the copper tubing so he lost all the refrigerant. The filter is in a vulnerable location. It's outside of the unit exposed to whatever could get to it with no support connected to it and 5/16" copper tubing. Why it's not inside the unit I have no idea. He told me in the first five years he has spent more than half in repairs than what he spent on the system.

Mine still has the original compressor. I'm waiting on the compressor to kick the bucket before I replace the system.

Will it pay for itself? My electric bill shows that my heat pump is the biggest energy hog I have. I can track it versus my kilowatt usage from month to month. That's why on the coldest or hottest month of the year my kilowatt useage may be as high as 4500 kilowatts but on months like March and October where the heat pump doesn't run much at all maybe as low as 1000 kilowatts.

I'm on the budget plan so my electric bill averages $220 a month and my house is 1600 square foot (top level). Based on other people around here with similar sized homes say their bills are about half that. But do they use natural gas in the winter to heat their homes?

If I spent 5 grand or whatever on one of those high deficiency heat pumps, would it cut my electric bill in half? Would I not have to make any repairs on it for 10 years?

I would be POed if I spent that much cash and didn't see my electric bill drop at least in half or had to replace the compressor after three years. If it did drop in half, then it might take four years to pay for itself if I didn't have to spend any money on repairs.

This maybe comparing apples to oranges but my '98 Chevy van with a 350 Vortex engine get's 9/15 mpg. It's paid for and runs well. Should I trade it in on a new Prius that get's better gas mileage? On the other hand I can't haul seven people in comfort with luggage on vacation or tow another car with a Prius.

I do know that the inside unit has a small leak in it. I do have to have the system topped off every 2 or 3 years in the spring when the A/C is turned on. Once again, usually the inside coil freezes over if it's not the filter.

I really have not had any major issues with it other than the motor going out on the air handler. Despite having to have those start capacitors replaced on the outside fan unit every three years. I asked the HVAC tech why these things were not lasting any longer than they did and he said, "Well everything is made in Mexico now and what that nation produces is pure junk". HMMM, that reminds me, I may need to check to make sure the outside fan is working. I seem to recall if the outside fan is not working will also cause the inside coil to freeze over but did not think that could happen in the winter on heat mode. I'll check this in the morning.

 

[TurboFiat124]

WOW! allot of replies!

One reason I've yet to replace this system is it still works.

That was when they built stuff to last. My father replaced his 25+ year old GE heat pump a few years ago when the compressor failed a second time with a Rheem unit. Boy did he get reemed! He said about three years after having the Rheem system installed, the compressor went bad and was not covered under warranty. Then he said something (a deer perhaps?) bumped the filter on outside unit which broke the copper tubing so he lost all the refrigerant. The filter is in a vulnerable location. It's outside of the unit exposed to whatever could get to it with no support connected to it and 5/16" copper tubing. Why it's not inside the unit I have no idea. He told me in the first five years he has spent more than half in repairs than what he spent on the system.

Mine still has the original compressor. I'm waiting on the compressor to kick the bucket before I replace the system.

Will it pay for itself? My electric bill shows that my heat pump is the biggest energy hog I have. I can track it versus my kilowatt usage from month to month. That's why on the coldest or hottest month of the year my kilowatt useage may be as high as 4500 kilowatts but on months like March and October where the heat pump doesn't run much at all maybe as low as 1000 kilowatts.

I'm on the budget plan so my electric bill averages $220 a month and my house is 1600 square foot (top level). Based on other people around here with similar sized homes say their bills are about half that. But do they use natural gas in the winter to heat their homes?

If I spent 5 grand or whatever on one of those high deficiency heat pumps, would it cut my electric bill in half? Would I not have to make any repairs on it for 10 years?

I would be POed if I spent that much cash and didn't see my electric bill drop at least in half or had to replace the compressor after three years. If it did drop in half, then it might take four years to pay for itself if I didn't have to spend any money on repairs.

This maybe comparing apples to oranges but my '98 Chevy van with a 350 Vortex engine get's 9/15 mpg. It's paid for and runs well. Should I trade it in on a new Prius that get's better gas mileage? On the other hand I can't haul seven people in comfort with luggage on vacation or tow another car with a Prius.

I do know that the inside unit has a small leak in it. I do have to have the system topped off every 2 or 3 years in the spring when the A/C is turned on. Once again, usually the inside coil freezes over if it's not the filter.

I really have not had any major issues with it other than the motor going out on the air handler. Despite having to have those start capacitors replaced on the outside fan unit every three years. I asked the HVAC tech why these things were not lasting any longer than they did and he said, "Well everything is made in Mexico now and what that nation produces is pure junk". HMMM, that reminds me, I may need to check to make sure the outside fan is working. I seem to recall if the outside fan is not working will also cause the inside coil to freeze over but did not think that could happen in the winter on heat mode. I'll check this in the morning.




Originally Posted By: sciphi
My wager would be dirty inside coil or low refrigerant level. Try the easy fix of cleaning the inside and outside coils with A/C coil cleaner spray. Rinse it out well with water, distilled if your water is liquid rock. It's about $6 a can at the box stores. After that, getting a reputable HVAC person out to check the refrigerant level might be advisable.

There's not much that can clog one of those super-cheap fiberglass filters. If it's a fancier pleated filter, those come in several different restrictiveness levels. Finding the most basic ones possible that flow the best would be better.

Any chance of posting pictures?


You want to see photos of my heatpump or the inside coil?

 

[Chris Meutsch]

Low refrigerant.

 

[bioburner]

The statement of needing to be topped off every 2-3 years is like saying the horse has a broken leg. R-12 and r22 (2015, source out-law.com)systems are not legal to be topped off anymore. Even if one gets it topped off it won't be right.
I am nursing my folk's AC system along. Needed bearings on the outside fan and a good cleaning of the condenser 2 years ago and is still going as the system is still sealed but was told if any loss of refrigerant the system will have to be replaced.
Getting a lump of coal from Santa not even a option

 

[zzyzzx]

Would I not have to make any repairs on it for 10 years?

You would have to make a lot of expensive repairs on it involving proprietary circuit boards. At least that's what I can tell. I am not convinced that these newer systems actually save you money in the long run.

 

[sleddriver]

Originally Posted By: TurboFiat124
WOW! allot of replies!
I do know that the inside unit has a small leak in it. I do have to have the system topped off every 2 or 3 years in the spring when the A/C is turned on. Once again, usually the inside coil freezes over if it's not the filter.

Bingo...refrigerant IS necessary whether in cooling or heating mode. Your leak needs to be fixed.

 

[TurboFiat124]

Well it was around 30F this morning. I stopped by my outside unit, the fan was moving and the house was warm inside. I did not check to see if the auxiliary heat was on or not.

But yes, it could be possibly it's about time to be topped off.

By the way, if R12 and R22 were supposed to be phased out of production, then why is there so much of it still available on Ebay?

 

[mk378]

In the winter, a heat pump's outside coil can naturally frost up since it is removing heat from the outside air, and it's already cold outside. So they have a defrost cycle:

Outside fan stops, compressor keeps running
Refrigerant reverses to pump heat from inside to outside
Electric heaters activated inside to prevent cold air from going out the ducts

This normally runs only for a few minutes at a time to thaw the outside coil. If it gets stuck that way, the inside coil could frost up.

I agree with most of the others, if that unit needs ANY repairs at all, time to replace it. It's a guzzler.

Also the last guy may have installed an oversized unit working into inadequate (for the unit's size) ductwork. This of course causes a problem in keeping the airflow up to the necessary rate. Oversized HVAC equipment doesn't do the owner any favors in terms of comfort or energy use.