ReplyPulling the coil out and cleaning it was probably your best last chance. Now that fins got bent even though you combed them out, I'd say its probably a lost cause.
Regular Guest
CAC/BDP AHU M #FB4ANF042 with a flat coil mounted on a 45 deg angle. As unit runs water builds up in the drain pan and eventually starts running over the lip [B]on the back side-the negative or blower-side of the coil.[B] Turn the blower off and the condensate drains right out. Blew the drain out (knew it wasn't that), rebuilt the trap (to make it deeper), lowered the blower motor speed,... it's looking like the coil is restricted; not so much that it's freezing though. There's a TXV that looks like it was added when the CU was changed out (within the last year). CU is Payne M #PA13NR042-J, S #1312X60488. System appears to be over-charged (9-10 deg total superheat, 20 degree subcool). AHU is on the 3d flr and someone wrote on the CU panel 17 lbs (factory charge is 7 lbs so they put 10 lbs in the lineset and coil???). Still, that doesn't explain the water leak. Tried to blow the coil out with N2, just bent the fins up. Combed them out and tried to clean with foaming coil cleaner. When I was blowing the Nitro through it I could barely feel any pressure on the other side of the coil. Maybe the blower is pulling air under the coil where it rests in the pan? Scratchin' my head still,... Going back Mon to try again. Going to end up condemning it if I can't stop it leaking.
Professional Member
Pulling the coil out and cleaning it was probably your best last chance. Now that fins got bent even though you combed them out, I'd say its probably a lost cause.
Regular Guest
What are the high and low preasures, type of refrig. Is return filters clean and or new? Is blower before or after coil? Im assuming its an upflow unit. This will give a better over idea of what this system is doing.
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Regular Guest
Ambient 82.4 deg F, refrg=R22 Head 210#, Back 59#, liquid 84.9 deg F, suction 42 deg F, it's upflow and the filter was plugged the first time I looked at it. Boars hair type, cleaned it and combed the dirty side of the coil and cleaned with mild detergent. Walked away thinking problem solved, call came back two days later.
Professional Member
I'd go ahead and pull the coil and drain pan. You'll be able to clean it a lot better and get air flowing through it and fins straightened out and be able to inspect the drain pan really well. Its very possible that there's a crack. Even if its full, you clean the trap out and you can still possibly have a leak somewhere else. Try cutting your drain line and seeing if there's water in your drain. Its one of those situations where you have to give it 110% or it will continue to haunt you.
Professional Member
I suppose it's worth making sure the motor and blower wheel are OEM and not replaced with a higher rpm motor, wrong wheel. Maybe just changing fan speed to lower setting on control board if high speed not needed but don't ice it up.
Regular Guest
Blower speed is already low as it will go, I can see the water coming over the edge of the pan and dripping down around the drain collar if I lay on my back and pull the edge of the cabinet out a little, pretty sure there is no crack, stopped up the drain and filled the pan up to check that. Took me quite a while to figure out where the water was coming from because it only leaks with the cabinet closed up and the blower running. Thought I had it cured at one point only to find the water was running around the bottom lip of the AHU cabinet and dripping in the back where I couldn't see it until I pulled the door back off. Probably will have to recover the charge and pull the coil tomorrow. Like to have a new coil to put back in it but it's so old I probably can't get one. Clean it and put it back and hope for the best (?)
Regular Guest
Coil could be screwed by now. Is there enough air flow through the coil? Before and after? Pressure could be not allowing p trap to drain right on neg pressure like said before. Does it call for a p trap? Had one the other day plugged in the trap where it just drained into 3" pvc vent for 2 story building. P trap was to prevent back gas from vent. Prob. Not code and ideally needs pump and or seperate run to basement. But that cost t & m.
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Member
Most rentals I go to have torn up coils from improper cleaning. Call and a/c guy out to come do the job right. Then put a good filtering system in it.
Regular Guest
Anytime the coil is on the negative pressure side of the blower you need a trap. I blew it out (the original P-trap) [I]and[I] rebuilt it with 90's so that I had at least 3" of water in the trap at all times. Didn't help. Will drill holes and check pressure drop across the coil with magnehelic tomorrow. Don't have coil pressure drop chart available though so I don't know what it should be. May be able to get it from Pierce Phelps,... should be less than 0.4" WC I think, based on a generic chart I do have. I'm just guessing though.
Regular Guest
truck12-are you saying I don't know what I'm doing?
Professional Member*
Um yes I believe we are. Blowing nitro through coil?
Regular Guest
well, ok, it wasn't my finest moment. I've done it before though, on looser finned coils. I stopped as soon as I saw what it was doing, only damaged about a two inch swath about 5 inches long. Easy for you to punch your keys in judgement now. I guess you never did anything you regret.
Professional Member*
sounds to me like you spent enough time messing with it, tell the customer its time for a new coil to match the new condensing unit.
maybe install a 5" media filter in the system and tell them how important keeping the filter clean is.
Member
Maybe you know what you're doing but you obviously don't know why you're doing any of it.Originally Posted by bodhisattva
That plus I'm sick of creating callbacks on myself because an owner has a rental with a water leak. The tenant had ruined the coil, but it's only 2 -3 years old how could that be, why are you telling me the coil is ruined it's only 2 years old. Looks like their 4 year old kid cleaned it.
You don't take a static pressure reading. Ok, maybe you know how but why?
It needs a pull and clean, thats only if the fins aren't torn to ****. Carriers, or whatever that carrier offspin number is are notorious for thick coils that get impacted. They may look clean if you brush it.
This is all pretty basic info and a simple problem.
I don't even screw with an owner/tenant evap coil thats been cleaned by some moron. You need to learn when to give up and either stop dicking around and make a decision or let someone do it for you.
Regular Guest
I know what I'm doing and I know why I'm doing it. The coil isn't that badly damaged. Like I said, I combed it out and I didn't damage it that bad to begin with. I would have pulled the coil to clean it if I had a recovery machine available. I'm trying to get this company up to speed as fast as I can but the $ for equipment has to be approved and go through "channels". Meanwhile I'm doing the best I can with what I have to work with. It's not ideal. I pretty much decided before I came on this site (looking for ideas) that I was going to change the coil and/or air handler.
Member
Can't pump it down?
Regular Guest
not with 17 lbs of refrig in a system with a factory charge of 7 lbs,.. didn't you read all the posts?
Member
So you don't have the tools to do the job. You've already decided before you came here that you're going to change the a/h or coil. So how did you plan on doing that?
Regular Guest
By getting the tools of course.
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