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AIr handling unit

Posted by chitra0828 (My Page) on
Fri, Aug 27, 10 at 15:48

Hi all: So our air handling unit is leaking. Last time it was a clogged drain, but this time the technician says it is a leaking drain pan. He further says that the coil and pan are one unit and so although the coil is fine, and only the pan needs replacing it is not possible to do it. Best to replace both, and since replacing both is about as expensive as getting a new system, get a new air handling system. Can someone please confirm that this is good advice? or do you think it is pretty feasible to just change the pan? Secondly, the tech also says that it should not be necessary to replace both teh compressor outside and the airhandler inside. (another shop i spoke with on the phone indicated that indeed given federal laws on 13cyr systems, we would have no choice but to do both at the same time). Does anyone have a comment on that too? It all feels really opaque and i'd appreciate any guidance you can provide. This is my first experience dealing with this issue.

Thanks Chitra


Follow-Up Postings:

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RE: AIr handling unit

There are air handlers available that work on your R22 and the new stuff. So you can replace just the air handler and then get a new outdoor unit later.


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RE: AIr handling unit

Even if the pan is attached to the coil, it can be repaired or replaced if the contractor really wanted to. mismatching a system is a bad idea unless you're really broke, but it isn't illegal to do so - sounds like both of the guys you've spoken to are less than honest. keep looking.


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RE: AIr handling unit

Im sorry, i am not clear on Zippyhvac;s comment. When you say mismatching a system you mean changing inside without changing the outside unit? Pls confirm i have understood this correctly. Another thing that had happened about 3 weeks ago was the the outside unit would not come on. When i turned on AC, the outside compressor would not come on. So the same guy came and replaced some parts in the outside unit. He did not think that anything needed to be checked inside. Is the problem outside in anyway connected with the issue inside do you think? ok i will try to find someone who is willing to change the pan. it does feel odd that one can't change a pan at all, and must change whole unit for that. Thanks so much all, and please let me know your thoughts on my reply.


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RE: AIr handling unit

Making a drain pan isn't a big deal for someone who knows how to bend tin - any hvac guy worth his salt either bends his own, or should have access to a tin shop than can do it inexpensively. Alternatively, he could probably get your pan sealed with a tube of caulk and a piece of "panning steel" for under $10... if he wanted to. it isn't rocket science.

As for mismatching a system by replacing just the indoor unit or the outdoor unit - lots of people do it and get away with it, but it's never an ideal solution - you'll never get peak efficiency from mismatched components, and you'll pay full price for the labor anyway, which is a significant portion of the cost. it's kinda like buying your shoes one at a time... they'll never match or fit right.

You mentioned the outdoor unit wouldn't come on - I wouldn't read alot into that - there are a number of components that could cause something like that - contactors and capacitors come to mind - it wouldn't be related to your leak, and they're unlikely to be very expensive - look over your repair order to see what the contractor replaced.


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RE: AIr handling unit

ok i will do that. Here's what i learnt today. The Air handler unit is the kind that has both a heating coil and a cooling coil in 2 different parts. So apparently teh coil and the pan are 1 unit. I was there while the technician checked. The model number is 940-1 or a 940-3. So the second guy (who had also said that the drain pan shoudl be capable of just being changed on the phone), acknowledged that it couldnt be done and it was better to get another unit. Then he called his supplier and came back with the comment that due to new codes established in 2010, new 410 units were the only ones being sold (am i saying it right)? and there was new Freon being used in them. As a result, if we didn't change both teh outside and inside unit at the same time then the stuff wouldn't work at all. Does any of this make sense to you all? and if so can you please advise if they are correct in their assessment? Here is the model number of the air handler (there were lots of different numbers!) 48MBXR-4HW. On the earlier compressor repair order, the technician had changed 1 dual capacitor, 1 magnetic contactor and added refrigerant (which will now all get wasted if we have to change the compressor too!)..Thx Chitra


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RE: Another couple points on the air handler

I jjust spoke with First Co of texas (which makes the air handlers we have installed), and here's what i learnt: a. The company does sell drain pans separately for the units called R22. So he is not sure why they cant change them.
b. The warranty on the whole unit is only 1 year! Can you believe that? And our unit was installed in 1999, so thats just crazy right there. c. The technical support guy clarified that we should be able to just change the R22 unit internally without having to change the compressor outside. The internal unit will work with the existing exterior unit. If however lets say we are able to change the drain pan and be done with it. Then lets say at some point we have to change the compressor outside, then we HAVE to change both exterior and interior units. So that might make the cost come down a bit Would you agree that all this makes sense? now we have to finda technician willing to change a drain pan! We live in Stamford, CT. Are there any technicians of integrity out here who would do so? Best Chitra


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RE: AIr handling unit

Please send me A.H.U. power and controling diagram.


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RE: AIr handling unit

The best thing that I've found in the past is to contact my specialist. Trying to work it out on your own often costs resources and time that you honestly don't have. I work pretty extensively with an air handling machine in our shop and generally don't try to mess with it (even though we're all engineers by trade). The last thing you want is an error with such an important piece of equipment. Here are the people that I generally go to for assistance: www.airhand.com

They're knowledgable and will help out with your questions/concerns.

Here is a link that might be useful: Air Handling Systems help


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