Chestnut

HVAC Question

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I believe my evaporator coil froze up. The fan is blowing nothing is coming out the vents and there is a lot of air blowing out between the main duct and the furnace unit, or between the evaporator coil and the blower.

If i get this thawed is the freezing a sign of a worse problem? Do i immediately need to call a professional or should I see if it's just the result of a lot of humidity in the house. The dew point is around 70 degrees.

My filter is new and i have 3 vents out of 20 closed. I have the vents close otherwise my basement gets too dang cold.

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Raising the thermostat cooling setpoint will ease the situation. If you can increase the fan speed, that will also help. I've done lots of HVAC controls stuff, but am not a refrigeration guy, so that's about all the suggestions that I have.

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34 minutes ago, Chestnut said:

i have 3 vents out of 20 closed

Have you always run it that way?  A major component of avoiding freeze-up is airflow - if there's not enough airflow (such as from when closing vents) then you can get freeze-up.  Also it can be an issue if refrigerant level is low.  We had an issue with our system freezing up until they made some changes in the vents and effectively increased airflow.

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Either something is dirty enough to inhibit air flow, or the refrigerant has leaked down to the point that the coils cool below freezing.  If it's fairly new, just call an HVAC guy.

Run it on fan only to evaporate the ice, and make it through the night, but I wouldn't try to run it frozen for long, or it will overwork the fan.

You might think that the refrigerant being low would not let it be cold enough to freeze, but with the exactly right amount of refrigerant in the system, it stays up above freezing, for now obvious reasons.  As it leaks out, it will let the coils get colder until it leaks out enough for it to stop cooling at all. 

This is why I can't understand why it remains legal for auto part stores to keep selling the little refrigerant kits.  I'm sure the vast majority of that stuff ends up in the atmosphere.

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Multiple suggestions require an technician to pinpoint the problem. Obviously there are several things that need to be checked. Hard to determine with a horse-back diagnosis.

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Call a professional.   It's probably something bad as coolant doesn't just purposefully leak from a sealed system, there's a failure...

We went through this with ours... it was a builder system, cheap and poorly installed.

Ours was about 10 years old when we replaced the evaporator coils... that lasted about 4 years before something else broke and since that repair was going to be expensive, I just went and replaced everything, AC and Furnace.   New system is more efficient, quieter, works better, and was installed properly.

The old R-22 is restricted now so it just keeps getting more and more expensive... 

 

 

 

 

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14 minutes ago, Minnesota Steve said:

Call a professional.   It's probably something bad as coolant doesn't just purposefully leak from a sealed system, there's a failure...

We went through this with ours... it was a builder system, cheap and poorly installed.

Ours was about 10 years old when we replaced the evaporator coils... that lasted about 4 years before something else broke and since that repair was going to be expensive, I just went and replaced everything, AC and Furnace.   New system is more efficient, quieter, works better, and was installed properly.

The old R-22 is restricted now so it just keeps getting more and more expensive...

Gonna wait and see if it happens again today. System worked well last year as its ghee first I've ran it this year.  Iirc i don't have 22 is R-xxx something with 3 numbers. Can't remember if it's 132 134 410 or other. The system isn't a bad one but it's getting on in age.

I would rather not get a new one they don't make them to last longer than 10 years it seems like which is s crook of ....

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New appliances suck. Replaced the logic board on a 2 year old dishwasher the other week. Might be time for a home warranty before it goes up, could be cheaper.

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In one of the museum houses that we look after, there is a refrigerator from no later than the mid 1950's.  It still works fine.  They want us to throw it away.  I hate to, but don't have a good place for it.  The last refrigerator we had lasted a little over 2 years, but the old one is too small for us.

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On the upside, newer HVAC units are far more efficient and much quieter. Same for appliances.

 

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21 hours ago, Chestnut said:

Gonna wait and see if it happens again today. System worked well last year as its ghee first I've ran it this year.  Iirc i don't have 22 is R-xxx something with 3 numbers. Can't remember if it's 132 134 410 or other. The system isn't a bad one but it's getting on in age.

I would rather not get a new one they don't make them to last longer than 10 years it seems like which is s crook of ....

Oh if you already have a R-410 system it may not be that expensive to recharge.

 

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Forest

7 minutes ago, Minnesota Steve said:

Oh if you already have a R-410 system it may not be that expensive to recharge.

 

Yeah i checked last night it's R-22. Yesterday the ac ran all day and didn't freeze. My bet is it's a combination of not a big enough blower for the unit low Freon high humidity and playing catchup.

Gonna call someone today or tomorrow. I put the fan to on not auto so that should help a bit.

18 hours ago, JohnG said:

On the upside, newer HVAC units are far more efficient and much quieter. Same for appliances.

 

If rather it be louder than a fright train and last longer than 10 years. The efficiency doesn't always pay either. More attic insulation usually yields better savings depending on what's there.

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8 minutes ago, Chestnut said:

Forest

Yeah i checked last night it's R-22. Yesterday the ac ran all day and didn't freeze. My bet is it's a combination of not a big enough blower for the unit low Freon high humidity and playing catchup.

Gonna call someone today or tomorrow. I put the fan to on not auto so that should help a bit.

If rather it be louder than a fright train and last longer than 10 years. The efficiency doesn't always pay either. More attic insulation usually yields better savings depending on what's there.

Our old AC started making more noise as the freon went low and it started failing. :-)

 

Don't just let them refill it and leave.... ask that they do a leak test, where they add a marker into the coolant that they can then detect with an ultraviolet light.   If  you have a leak and you add more coolant it'll just leak out again.

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