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Drainage under packaged heat pump

5K views 18 replies 6 participants last post by  salonica 
#1 ·
I recently had a new Trane packaged heat pump installed, and the heat ducts go at an angle down into my crawl space. The heat pump sits on 4 adjustable plastic legs which elevate it about 3" off the pad. To help me keep out critters from coming in under the heat pump, the installer screwed on a strip of 3"sheet metal edging running down from the bottom of the heat pump to cover the spacing between the bottom edge of the heat pump and the pad, around the 2 sides and front of the heat pump. The back of the heat pump has an insulated shield over the ducts going into the crawl space. However, I have been having a problem with some of the heat vents inside having a wet plaster smell, as well as the same smell in the return air duct opening inside. Does anybody know if it is possible that the metal edging covering the edges between the bottom of the heat pump and the pad is causing a drainage problem and/or possibly an overheating problem? Does there have to be an open space or openings beneath the bottom of the heat pump and the pad?
 
#4 ·
Thanks for your response. Unfortunately, I don't have the picture sending capability. It is a new Trane packaged heat pump, which sits on 4 plastic feet, which raise it about 3 inches off the pad outside. We have screwed a 3"' approx. wide strip of sheet metal around the sides and front of that 3"" space between the heat pump bottom and the pad, (to try to keep critters from squeezing under the heat pump and into the crawl space, by squeezing around the ducts or between the ducts.) My question is will that cause rainwater not to be able to get out from under the heat pump and accumulate, or maybe go back down into the ducts or crawl space? And/or could enclosing it underneath like that cause anything to overheat inside? i.e., does it need that open space beneath for heat to come out? Has anyone ever put a metal strip around the bottom of their packaged heat pump to keep out mice and chipmunks (which abound in my yard and are attracted to warmth)? The 8 or 10 packaged heat pumps I've seen in neighborhoods don't have the bottom enclosed roundabout, you just see the plastic feet holding up the unit. (but maybe they have a better fitted opening around the ducts than I do.) I am trying to figure out if this was the wrong thing to do to enclose under a packaged heat pump for some reason, or could be causing moisture or overheating problems, as there are some odors in the ducts. Has no one else ever had mice etc. try to squeeze in under their outdoor packaged heat pump into their crawl space?
 
#5 · (Edited)
I live in the south so I've seen hundreds of heat pumps but not one of them has the sheet metal your taking about.
The ducts and the area where it goes into the foundation should have been sealed up and nothing should be able to get in there.
Now that someone has made that enclosure if thay can get in there it would be a nice sheltered spot for them to move in. If it was left open they would have no intrest in a open area to build a nest.
An no the heat does not blow out in that area. It blows out the back.
The bottom of any unit Ive seen is soild so there no chance that odor is coming from there.
 
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#7 ·
THANKS for your kind information! Sounds like probably I should take the metal strip off. The brick was knocked out irregularly and too large around the ducts, which go downward at an angle and thru the wall. I tried and tried to find an installer that could make a metal shield going from the back of the unit all around the back ducts and attaching to the wall all around the opening but they said they couldn't figure out how to make one, because of the slanted ducts into the opening. They also kept saying don't brick the opening tighter up around the ducts opening before they come to install it, because they might have to change the opening to install it. Then after they installed it, they say if I get it bricked up now (now pretty hard to do with the heat pump and a small overshield screwed and caulked in place that only goes down to the ground level, not down to the opening below ground level), the brick might have to be knocked out again if changes need to be made. ???? So I am thinking maybe I can get the sides of the brickwork opening made straight, and maybe someone can figure out how to insert a metal wall part, rather than brick, behind the duct area, maybe with some pressure treated wood posts in the opening to fasten the metal to, around the ducts so they could tear that out if they had to sometime. Then maybe they could fasten a shield to that to go all the way around the ducts to the wall. (They all say that critters can also get through BETWEEN the 2 ducts too, where they seem to think it is apparently almost impossible to put something between the ducts that would keep them out of the crawl space!) It seems nobody has any solution! Apparently it went for years with the last one this same way, before I was dumb enough to buy this house, hence the inherited critter problem. I guess most people don't have so many determined chipmunks, etc. in their area.
 
#9 ·
These metal covers are made all the time On packaged units like yours.
Without some pictures to try and see exactly why they think it can not be done were going to be at a loss.
The ones I've seen were made in two pieces, one in the shape of a letter C and the bottom one was just a flat sheet with the two ends bent up so it could be attached to the other piece to form what would amount to a rectanguler tube. The whole thing get screwed to the heat pump and the brick wall.
 
#10 ·
A hood or shroud is standard on any heat pump installation around here, you certainly won't pass your inspection without one. If it is constructed and sealed properly, NOTHING should find it's way into your crawl space, rainwater, critters.....nothing. If you can verify that rainwater is intruding through that hole in the wall you need to call the contractor back out to fix it.
 
#11 ·
I appreciate your inputs very much. I appreciate Joe's description of how some shrouds are made that go all around the hole from the unit to the wall. It isn't just the discharge (duct?) end that is blocked off, the metal strip goes around the two sides and front. It seemed they couldn't put it across only the back and toward the wall, which I think would have been better. The problem with pictures would be that you can't see anything much. I wouldl have to take the above-ground shroud loose (screws and caulking), and there are some cemented bricks, which go down a little way into the ground under both sides of the 2 side of the shroud, which I guess sooner or later will have to be removed so anyone can replace properly (with metal?) or see what is going on. I have temporarily piled bricks from the inside around the ductwork to keep out the cold, but they are not a very good barrier to critters that can tunnel underground, apparently even from some distance away.

It seems from what has been said here that an all-around shroud to the wall could be done, just that the bigger heating contractors don't want to get involved with that part of selling a heat pump (complications). Especially since it is hard to see and get to what is down there because of the cemented bricks on both sides of the duct on the outside, plus the new screwed on above-ground shroud. And I suppose it will be very expensive to make such a better all-around shroud. Maybe I can find some independent smaller contractor or metal person that can figure out how to do it. The heating contractors hate crawling inside to look at it, and they don't do it. I can't blame them, I guess!

Thanks again for your answers.
 
#12 ·
It seems that it is the fact that the bottom part of such an all-around shield would have to go downward at a sharp angle from the heat pump and affix at an angle to the wall that bothers them the most. Apparently if it went straight back they would be more willing to do it.
 
#14 ·
I almost never see one that lines up with out having an angle.
It could be the company is new, does not have a metal shop, or there just sending out the wrong person to work on the job.
 
#15 ·
If they can't build a duct hood on the job sight from a piece of flat metal then they are not prepared to do the job. From the OP's description it sounds like his might be a little tricky, but it still has to be done right.

There are lots of "tricky" parts to this job. If they can't build a hood, it makes me wonder where else they fall short. At least there's not much to botch setting a package unit. If you had told me they installed a split system but couldn't do basic sheet metal work I would really be concerned!
 
#16 · (Edited)
I don't think there is any requirement for an inspection here in this part of Tennessee, plus this is in the County. They did build the top part of the shield on site, but not a bottom to it, it just goes down to the cement (over a few bricks on the sides). I think they were reluctant to offer a price or to say they could do it because of the cemented bricks that they couldn't see under without demolishing, and didn't know how long it would all take or whether it would work. it seems that, perhaps because of all the business they have been getting from installing the energy efficient rebateable heat pumps, that at least the larger contractors don't want to get into any but straightforward situations. I had asked if maybe they could take loose the old unit when bringing the new, and allow me some time with the unit away from the wall, in order to have someone repair the brick wall around the ducts and we could take out the other cement below ground that is in the way. But none of them wanted to do that because they would have to make a second trip, to come back and connect. I talked to 3 of them, and none of them seemed to want to build a shield all the way around the ducts between the unit and the wall. The hole which was knocked in the wall (apparently years ago) around the ducts was also quite wide, and pieces of sheet aluminum had been screwed to cover some of it that was outside the former shield. Now it is quite cold and wet here; maybe I can do some more makeshift things until I can try to find some other people who could make a complete shield. The company seemed very nice, and I suppose that they didn't charge as much as if they had tried to do all that. They don't break the cost down as to what is installation costs. But it seems maybe they should have told me it would result in a problem not to have the shield all the way around the hole and ducts. I guess a lot of people have not had all kinds of critters from the woods and neighbors around their house. I thank you all a lot for your replies.
 
#17 ·
If there is no inspection requirement (which seems moderately to severely unusual) you're probably stuck. I find it hard to believe your locality lets any Tom Dick or Harry do HVAC work. There's a lot of things that can go wrong if that's the case, but if that's what's up you're probably screwed.

Post pics of your problem, someone here can at least provide you with some harm reduction advice.
 
#18 ·
This is what I would do. Call several other companys and tell them you got screwed and want them to come out and look at it and see what they can do to get this taken care of. But the way to get them to come out is to also tell them if they can do it you will let them come out and do the annual maintaince on the HVAC system.
 
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