Author Topic: HVAC question  (Read 1204 times)

jehovasfitness23

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HVAC question
« on: February 27, 2021, 10:22:26 AM »
Any HVAC techs or other knowledgeable people?

Background. 5 yr old unit, problem started 1.5 yrs ago.

Problem was that I had a minor "flood" of water coming out of the bottom of the indoor unit and out of the closet it is in.

Company came out said that piston valve (or similar) may have gotten stuck or the line clogged and needed clearing (not condensate line). They "fixed" it and also recharged system.

Unit performed for 5 months with little problem that I could tell (AC).

Next time similar but different problem maybe same but perhaps I caught it in time. Anyway, went to change filter and noticed a small amount of water that was dripping onto the filter. Not enough to pool below filter and onto the bottom pan (not drain pain) and out of the unit.

Company came out, recharged system but couldn't note a problem. Persisted. Came out again and after I looked myself a few times noticed that the drip was actually coming from above where condensation was building on the blower fan housing and dripping down onto the evaporator coil and then thru (rather than drain pan/line) and onto the filter and eventually smaller amounts on the bottom pan (again not drain pan) of the unit.

Company said they had never seen condensation build up on the blower fan housing. My brother who works for the company then came out to clean the evaporator coil but it was in fairly clean shape from his view but he still cleaned it. Problem still persisted, then cold weather came so now I'm waiting for warmer weather to see latest status.

Any idea what's going on here? To be clear, it's not a drain pan or drain line issue as that is functioning fine, plus that's not where I saw the condensation problem coming from.

For what it's worth, a google search on the brand has stated the company had been known to have defective evap coils that could leak coolant/refrigerant. Could such a leak cause condensation issues above the coil?
« Last Edit: February 27, 2021, 10:25:06 AM by jehovasfitness23 »

MrTurtle

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Re: HVAC question
« Reply #1 on: February 27, 2021, 12:20:47 PM »
Do you have a make/model number for the unit?  It seems very strange that the air has enough humidity for water to condense on the fan after going through the cooling coil.  The good news is it most likely isn't a refrigerant leak.  That would just cause poor cooling performance and ozone layer depletion.  Possible things I can think of:

Air is going too fast (over 500 FPM) through the cooling coil and blowing water off the coil.  If that's the case, slow down the fan.

If your fan runs constantly, you might be cooling it down when the unit is in cooling and when the compressor turns off, you are now running warm, humid air through a cold fan and water condenses on the fan.  If that's the case, changing the thermostat setting to "AUTO" instead of "FAN" will help.

I am interpreting your problem wrong and the water is condensing on the OUTSIDE of the fan, meaning out of the airstream.  If that's the case, the fan is being cooled (by the cold supply air) to below the dewpoint of the air around the fan.  Maybe insulate the fan somehow?  Maybe seal the unit better so hot garage air doesn't get in?

Those are my best guesses as an HVAC engineer, which is completely different from an HVAC technician.  Hope that helps!

jehovasfitness23

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Re: HVAC question
« Reply #2 on: February 27, 2021, 12:37:52 PM »
thanks.

Make is Nortek Model # B6BMM036K-B

Fan is set to auto already.

The hvac tech did mention that the motor had "odd wiring" design to it. Something along the lines of the speed of it but he said the blower motor may be going bad. Sorry that's about all I can recall as well as my limited knowledge of hvac systems.

The condensation is forming on the under side of the fan housing, above the coil, so that kind of leads me to your input about the fan speed being too fast and drawing condensation up

That said, everything was working fine for the first 3ish years of the unit, so I find that odd it would just now be an issue if it is coming from the fan speed.

My brother did have me seal the unit up best I could, again never an issue before. So I did put masking tape near the breaker switch on the unit as well as near the access panel/condensate line and made no difference. The unit is in a closet in our garage which maintains a consistent 60-70* in the Summer, though I'm not totally sure on humidity as that can change depending upon if the garage doors are open, we are in MD so it can get 90% humidity for days in a row. I usually try to avoid leaving garage doors open long in those conditions.
« Last Edit: February 27, 2021, 12:39:42 PM by jehovasfitness23 »

KarefulKactus15

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Re: HVAC question
« Reply #3 on: February 27, 2021, 12:46:17 PM »
Not a tech.

But a picture would be super helpful. As someone else said brand and model number as well helps.

If you have a normal split system and no fancy upgrades like a humidifier...... It's humidity in the air condensing. Why it's funneling incorrectly is the question and a picture would help. 

This assumes everything else is working correctly and the problem is readily repeatable and not showing up after a refrigerant leak or other in ordinary situation.


And to illustrate how strange things can happen. I had a gas leak once on a system - with no gas connection. But sure as shit everytime we turned on the system propane smell blew through the house and we traced it back to the gasless hvac system .    After investigation it appears a squirrel or other rodent had drug an old bic lighter into the unit and it must have busted open from the temperature / when the unit turned on.    I don't think this relates to your situation other than strange things happen from time to time.

jehovasfitness23

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Re: HVAC question
« Reply #4 on: February 27, 2021, 01:07:49 PM »
Not a tech.

But a picture would be super helpful. As someone else said brand and model number as well helps.



Attached is a pic of the fan/housing, the droplets form under the fan on the underside of the cover for it.

Another pic is the underside of the coil, you can see some droplets that were already dripping through from the topside of the coil after they dropped down from the fan housing.  If the coil looks dirty here it has since been cleaned but that's how it looked from never being cleaned since new (5 yrs)

Another pic shows the water droplets eventually making way thru filter.

Previously AC season it was so bad it pooled out of the closet into the garage, so I either caught it early this time or it's not as severe as before.

jehovasfitness23

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Re: HVAC question
« Reply #5 on: February 27, 2021, 01:11:22 PM »
coil

jehovasfitness23

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Re: HVAC question
« Reply #6 on: February 27, 2021, 01:18:51 PM »
pan area below coil (not drip pan of course)

KarefulKactus15

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Re: HVAC question
« Reply #7 on: February 27, 2021, 03:57:51 PM »
Thanks for the photos. The above engineer offered good thought on a high rate of speed taking moisture off the coil.  I have my own thought but ultimately its guesswork while we work through this.

Can you include 2 more photos?

A full frame photo of the outside of your unit with the condensate line in view.

A second photo that's closer up of where exactly the drain line for the evap coil comes out and if its a straight line with a vent or P trap. (Depending on positive or negative pressure side for which is used)



I know you say your drain line is functioning correctly - How have you verified this? I want to make sure it wasn't installed incorrectly in such a way that when the AC runs for long periods of time there is a pressure issue from incorrect install that prevents proper draining that only shows up when the fan is on and there is long enough run time with enough moisture removal to fill the drain tube.  - Once the tube is full it would be backed up onto the evap coil at which point the air could carry the backed up / non draining water up to the fan housing more easily and allow water to exit your unit in a way that it was not designed for.    - This is all speculation but I want to rule it out.  It sounds like your brother would have your best interest at heart so hes obviously checked all the super common stuff. Also Im surprised there isnt a final drain pan that is a catch all for anything that might have escaped the evap condensate pan. (The big outside picture will elaborate on this) 


I guess a good place to start for internet troubleshooting if you so dare - What tools do you have available?

1.) Do you have any tools that can check pressure differential?
2.) Do you have any tools that can check air flow?
3.) Do you have any tools that can accurately check humidity and temperature - or jump straight to the good stuff and check wet bulb temp?

I don't expect you to have any of the above, but it never hurts to ask. You never know what people have collected over time. The real shame is that you cant make it do it with the cover off since it changes the conditions so much. Would be alot easier if you could just watch it happen lol.
« Last Edit: February 27, 2021, 04:00:10 PM by Kroaler »

jehovasfitness23

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Re: HVAC question
« Reply #8 on: February 28, 2021, 06:31:44 AM »
Thanks for the photos. The above engineer offered good thought on a high rate of speed taking moisture off the coil.  I have my own thought but ultimately its guesswork while we work through this.

Can you include 2 more photos? I'll snag them later today

A full frame photo of the outside of your unit with the condensate line in view.

A second photo that's closer up of where exactly the drain line for the evap coil comes out and if its a straight line with a vent or P trap. (Depending on positive or negative pressure side for which is used)



I know you say your drain line is functioning correctly - How have you verified this? Few ways perhaps. 1. I can see the water droplets hitting the coil from above and dropping thru onto the filter when I take the front cover off, so I assume that's why the filter is wet in the center rather than the edges. Of course I'm using an educated guess here. The line post trap is clear b/c I can dump water/bleach in the trap and it will go through the pump and out the house. There could be a clog perhaps pre-trap from the pan out the unit but I don't recall any water collecting there, then again maybe it did and I've forgotten but most of the water when it pooled out the first time was from the bottom of the air return pan area. There's also a float switch that if the line gets backed up in the trap area it shuts unit down.

I should add that the drip pan (plastic) did have some sludge lining the bottom that I cleaned out best I could, but it was more a thin mucous type layer and didn't seem to reach the level of blocking the flow out to the line.




 I want to make sure it wasn't installed incorrectly in such a way that when the AC runs for long periods of time there is a pressure issue from incorrect install that prevents proper draining that only shows up when the fan is on and there is long enough run time with enough moisture removal to fill the drain tube.  - Once the tube is full it would be backed up onto the evap coil at which point the air could carry the backed up / non draining water up to the fan housing more easily and allow water to exit your unit in a way that it was not designed for.    - This is all speculation but I want to rule it out.  It sounds like your brother would have your best interest at heart so hes obviously checked all the super common stuff. Also Im surprised there isnt a final drain pan that is a catch all for anything that might have escaped the evap condensate pan. (The big outside picture will elaborate on this) 


I guess a good place to start for internet troubleshooting if you so dare - What tools do you have available? 0 tools and 0 knowledge on using them, i'm pretty useless when it comes to DIY stuff. Even taking off the front cover of the hvac was a huge step for me to even look inside.

1.) Do you have any tools that can check pressure differential?
2.) Do you have any tools that can check air flow?
3.) Do you have any tools that can accurately check humidity and temperature - or jump straight to the good stuff and check wet bulb temp?

I don't expect you to have any of the above, but it never hurts to ask. You never know what people have collected over time. The real shame is that you cant make it do it with the cover off since it changes the conditions so much. Would be alot easier if you could just watch it happen lol.

answers above in red
« Last Edit: February 28, 2021, 06:33:28 AM by jehovasfitness23 »

lukebuz

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Re: HVAC question
« Reply #9 on: February 28, 2021, 07:22:38 AM »
Make sure you have a "U" trap on your condensate line.  Otherwise the suction from the fan will suck the water right out of the condensate line and blow it all over the place.  BTDT

jehovasfitness23

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Re: HVAC question
« Reply #10 on: February 28, 2021, 08:20:31 AM »
Make sure you have a "U" trap on your condensate line.  Otherwise the suction from the fan will suck the water right out of the condensate line and blow it all over the place.  BTDT

It does.

On another note- question. How do I determine total amps? Looking at getting a generator or standby and big concern would be being able to run heat pump.

On the unit specs (outdoor unit) it states the following:
total amps: 17.8
delay fuse max: 35
min circuit ampacity: 22

It's a 3 ton unit and I'm not sure about indoor air handler amp, the label says min circuit ampacity 2.6 and max over - current protection 15

Quick google search says a 3 ton would be normally 30 amp, but going by above stats I'm not sure if mine is 17.8, 35 or 22 when trying to determine generator size

KarefulKactus15

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Re: HVAC question
« Reply #11 on: February 28, 2021, 08:24:31 AM »
Make sure you have a "U" trap on your condensate line.  Otherwise the suction from the fan will suck the water right out of the condensate line and blow it all over the place.  BTDT

So this is the first thing I want to rule out.   I doubt you have a physics defying HVAC system so a couple of things are possibly happening and that's about it, no magic, no extra source of moisture.

1.) The condensate is not draining correctly for various reasons and is being blown up to the fan area. (This issue will be interesting to troubleshoot cause if you take the side cover off, it will appear the drain is working right because you changed the pressure balance. If you dump water down the drain, it will appear it is working right.... But when the system is running with the cover on with only gravity drain and the fan on, it may not work correctly.

2.) There is an external air leak exactly or around where the water is pooling. As the HVAC engineer above posted, if warm HUMID garage air is being sucked in at that area , the blower metal is going to be below the dew point most of the time and condense the moisture in the air.   I do not think this is the most likely issue unless its super humid where you live and a very direct link.

3.) Again taking from the poster above - the CFM rate is too high and taking the condensate off the coil instead of allowing it to drain.

4.) Some freak incident that isnt apparent to us at this stage of the troubleshooting. (Most likely to least likely as we narrow down that the key components are working as intended)


Ill be waiting for those photos but the more information about the symptoms you give the more we have.

1.) Is the issue readily repeatable?
2.) You indicated it only happens on high heat / humid summer days and does not occur during the winter?
3.) The day you took the photo and noticed it in the winter - Do you remember the temperature and humidity that day for your area?


As a follow up question about proper drainage (You see I want to rule out the drain first) - When the system is running on a humid day, can you visually see a stream or steady drop coming from the external outlet of the condensate drain?   (We can get more specific about how much should be coming out based on temp / humidity, but first a simple visual check for yes or no is a start. It needs to be checked with the all covers on and in normal unit operation condition) *Update - Be sure it is the CONDENSATE drain dripping and not the overflow line dripping. I hate to send us down an incorrect assumption by verifying the wrong line*

« Last Edit: February 28, 2021, 08:32:49 AM by Kroaler »

MrTurtle

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Re: HVAC question
« Reply #12 on: February 28, 2021, 08:26:28 AM »
Make sure you have a "U" trap on your condensate line.  Otherwise the suction from the fan will suck the water right out of the condensate line and blow it all over the place.  BTDT

+1 to this.  Also, if the trap looks like pic related, that doesn't count.  It needs to be deeper.  2" or more should be safe for your model.


jehovasfitness23

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Re: HVAC question
« Reply #13 on: February 28, 2021, 09:18:05 AM »
Make sure you have a "U" trap on your condensate line.  Otherwise the suction from the fan will suck the water right out of the condensate line and blow it all over the place.  BTDT

1.) Is the issue readily repeatable? during the summer when AC running. Never when heat is running.
2.) You indicated it only happens on high heat / humid summer days and does not occur during the winter? No b/c the evap coil I assume is not being used to cool.
3.) The day you took the photo and noticed it in the winter - Do you remember the temperature and humidity that day for your area?  Did not happen nor does it in winter, pic is from the summer.


As a follow up question about proper drainage (You see I want to rule out the drain first) - When the system is running on a humid day, can you visually see a stream or steady drop coming from the external outlet of the condensate drain?  Yes, water is clearing heading outside and draining out (We can get more specific about how much should be coming out based on temp / humidity, but first a simple visual check for yes or no is a start. It needs to be checked with the all covers on and in normal unit operation condition) *Update - Be sure it is the CONDENSATE drain dripping and not the overflow line dripping. I hate to send us down an incorrect assumption by verifying the wrong line* what is difference b/w condensate line and overflow line? the indoor condensate pump functions and pumps that outside

jehovasfitness23

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Re: HVAC question
« Reply #14 on: February 28, 2021, 09:20:58 AM »
Make sure you have a "U" trap on your condensate line.  Otherwise the suction from the fan will suck the water right out of the condensate line and blow it all over the place.  BTDT

+1 to this.  Also, if the trap looks like pic related, that doesn't count.  It needs to be deeper.  2" or more should be safe for your model.



Oh it's definitely a legit 2" one

KarefulKactus15

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Re: HVAC question
« Reply #15 on: February 28, 2021, 02:01:02 PM »
Make sure you have a "U" trap on your condensate line.  Otherwise the suction from the fan will suck the water right out of the condensate line and blow it all over the place.  BTDT

1.) Is the issue readily repeatable? during the summer when AC running. Never when heat is running.
2.) You indicated it only happens on high heat / humid summer days and does not occur during the winter? No b/c the evap coil I assume is not being used to cool.
3.) The day you took the photo and noticed it in the winter - Do you remember the temperature and humidity that day for your area?  Did not happen nor does it in winter, pic is from the summer.


As a follow up question about proper drainage (You see I want to rule out the drain first) - When the system is running on a humid day, can you visually see a stream or steady drop coming from the external outlet of the condensate drain?  Yes, water is clearing heading outside and draining out (We can get more specific about how much should be coming out based on temp / humidity, but first a simple visual check for yes or no is a start. It needs to be checked with the all covers on and in normal unit operation condition) *Update - Be sure it is the CONDENSATE drain dripping and not the overflow line dripping. I hate to send us down an incorrect assumption by verifying the wrong line* what is difference b/w condensate line and overflow line? the indoor condensate pump functions and pumps that outside

I cant speak to your area or the code there, but in my area there is typically a condensate line, then a different drain line for the catch pan.  But I dont know if that applies to you. It may not be required in a garage install.

TBH - This will be challenging to resolve without actively being able to recreate the problem. The rust color stained metal from where water collects and moves will be your best troubleshooting tool for whats happening while it cant be recreated.

 

Wow, a phone plan for fifteen bucks!