View Full Version : Is my new system correct?
Greetings, I'll try to keep this as concise as possible.
I have a section of a house that is approx. 1,200 sf. The contractor, using the old 1-ton/500 SF method came up with a 2 1/2 ton system with the condensing unit pad mounted outside and the AH/furnace/coil mounted horizontally in my attic. What wasn't considered is the large number of windows, the 9' ceilings and below standard insulation (it's an old house). BTW, we live in an area where 100 degree temps are the norm this time of year.
Anyway on to my problem. This new system will only cool the mentioned section of the house to 84 degrees during the day and that's only because some cooler air from second system is being drawn near the t-stat/return giving somewhat false reading (actual room temps are very high 80's). Also, the system runs 100% of the time during the day. At night I can get it down to the high 70's but it runs nearly constantly too. The HVAC guy says the system is correctly sized and it's not uncommon for it to run all day and all night. I don't think that's correct and believe a bigger unit should have been used.
What say the pros?
BaldLoonie
09-08-2006, 12:42 PM
Rules of thumb don't work. Sure sounds undersized unless there are operational problems with the unit or duct issues keeping you from getting full cooling.
We have a customer in just today with a 2.5 ton on a 1500 sq ft ranch. He keeps it 62° even in 90+ weather. How we haven't a clue :D
Originally posted by BaldLoonie
Rules of thumb don't work. Sure sounds undersized unless there are operational problems with the unit or duct issues keeping you from getting full cooling.
We have a customer in just today with a 2.5 ton on a 1500 sq ft ranch. He keeps it 62° even in 90+ weather. How we haven't a clue :D
Oh, there have been plenty of duct issues, most notably being the back bedroom (fartherst from the coil) getting very little air (he's readjusted dampers and vents no less than a dozen times, taped and sealed three or four times, installed an in-line fan...what a mistake this was, and eventually double wrapped ducts). Even so, a very small bathroom at the end of the coil gets tons of air but still doesn't get cold even with the door shut.
captainrat
09-08-2006, 01:02 PM
pro says youum wentum cheap & now in bind !
hackum gotcha withum drunk paleman sizin & duct inspection.
seriously you have to have an evaluation of the structure, insulation,windows, etc, condition & sizing of duct. Manual J etc
anyone who would make such assumtioms at the homeowners expense certainly cannot even be trusted to properly install setup & startup equipment. they wouldnt have the proper instruments or training. some tape & a set of gauges wont do it.
a good contractor wont do any job that wont perform when finished.
You HAVE TO properly INSULATE !probably renovate duct ( properly ) not the way this guy does work & install properly sized equipment properly.
this post is typical of the customers that say we are to high :-)& go with the hack.
now you have to start over again with a competant contractor.
4X4,
How can they say it's sized right if it can't cool the house??
That said,it could be design,installation or equipment problems.
What temperature of air is comong from the supply ducts ,and what is the return temp.?
Location,model numbers??Pictures often help,if you can.
Type of construction,insulation R values in walls,floor ,ceiling?
Captain, the prob is, without getting into $$$ specifics, I paid very handsomly for this job....money was not a factor from the start as I didn't even bid it out. All I've ever wanted was a job done right.
Dash,
It's a Feb. 2006 manufacture 14 seer Ruud (I don't have the model # with me) heat pump.
The vent temps vary depending on how far from the coil, but are generally in the upper 60's. I've never measured the return air temp, but he says it's a 20 degree split, so I presume upper 80's.
The house is 1950's construction on slab with concrete block exterior walls (hollow) and a built-up flat roof. I have 3/4" rigid insulation in the furred-out walls and R 25 in the ceiling rafters. All the windows are brand new and are alum. framed, double paned with Low E.
captainrat
09-08-2006, 01:25 PM
man thats terrible,sorry for your situation, was this guy licensed ? what state are you in ?
it sounds like your far from the worst on insulation.
get us some pictures of ductwork installation & such.
did you get the right air hanlder, variable speed ?
post the models #s of each piece, baldloonie will know if its the right match
[Edited by captainrat on 09-08-2006 at 01:28 PM]
Yeah, the guy is licensed and we're in S. Texas.
He's saying I need more insulation and to "treat" all my windows. But we live in the country and don't want to install any window treatments. I guess my point or question is, shouldn't my insulation and window situation been considered when designing the system? I don't feel like I should have to do anything over and above what I've done and if a larger unit is the simple solution that's what needs to happen.
I can get pics up this evening.
BTW, thanks for all the help so far.
pecmsg
09-08-2006, 02:24 PM
Originally posted by 4x4
I guess my point or question is, shouldn't my insulation and window situation been considered when designing the system?
That’s the best statement I’ve heard in a while. YES it should have.
Was a heat load/loss calculation (manual J) done? It should have been given to you when you signed the contract. Probably not. Click on the link above “ HVAC Calc. Pay the $50 and do your own. Post your findings along with the make & model #’s of both the indoor and outdoor units.
Originally posted by 4x4
Captain, the prob is, without getting into $$$ specifics, I paid very handsomly for this job....money was not a factor from the start as I didn't even bid it out. All I've ever wanted was a job done right.
Dash,
It's a Feb. 2006 manufacture 14 seer Ruud (I don't have the model # with me) heat pump.
The vent temps vary depending on how far from the coil, but are generally in the upper 60's. I've never measured the return air temp, but he says it's a 20 degree split, so I presume upper 80's.
The house is 1950's construction on slab with concrete block exterior walls (hollow) and a built-up flat roof. I have 3/4" rigid insulation in the furred-out walls and R 25 in the ceiling rafters. All the windows are brand new and are alum. framed, double paned with Low E.
If the air handler is the "short" one,the duct coming off the air handler ,must be the exact size as they "takeoff",much narrower then the cabinet,if it's the width of the cabinet,on that air handler,it's may be the whole problem..
The blower is mounted at the top of the cabinet,there was a bright tag telling them to "bend " the takeoff tabs up,and to install the duct the same size,for 18"(or something like that).
If either of these things were not down it reduces air flow and btu capacity.This is a very common mistake in our area.
typed this a couple of hours ago,forgot to hit submit!
pecmsg
09-08-2006, 03:27 PM
Dash
I forgot about that one. Good Call
Wasn’t it 36” with no takeoffs?
36" tall sounds right,supply take off needs to be bent up 90° from where it is ,out of the box.
4X4,If this is the case,be sure the check the refrigerent charge,after correcting the tak off,and restoring proper air flow,it will be needed.
As requested, here's some more info and pics.
Condensing unit UPNE 030JAZ
AH UHSA(L)- HM3017JA
After looking up model numbers, they are NOT 14 SEER as previously indicated, but 13 SEER.
These are a few of the pics I took. I hope they offer the details you need, if not, I can take more.
Thanks.
http://i2.photobucket.com/albums/y41/jimsimm/IMG_4978rs.jpg
http://i2.photobucket.com/albums/y41/jimsimm/IMG_4982rs.jpg
http://i2.photobucket.com/albums/y41/jimsimm/IMG_4990.jpg
http://i2.photobucket.com/albums/y41/jimsimm/IMG_4992.jpg
Gunnery Sergeant Hartman
09-09-2006, 12:03 PM
Man, you got hacked!
The duct insulation looks like crap. The suction line is missing about 2-3 ft. of rubitex insulation.
No inspection I presume...
pecmsg
09-09-2006, 12:20 PM
Is this all new, Equipment and ducts?
I don’t have that model install manual here but I still think you need 36” of duct coming off that unit. Someone from RUUD can confirm.
I love the location of the A/H. My knees & back ache thinking about getting to it. Could they put it a little further back?
Suction line in the attic missing armor-flex, and from the pictures what’s there is too large.
Cover the line set, extend the drain, cover LV wiring. The list goes on & on
I will say I do like the use of round pipe instead of flex, but there not done yet.
Please tell me they haven’t been paid in full.
udarrell
09-09-2006, 12:37 PM
I did not read all the posts, but beliieve you should check the Return Air at the room RA Grille & at the blower. If it is higher at the entry to the blower, it is drawing hot air from other than the conditioned rooms.
Also, check the temperature rise of the condenser air discharge above the ambient! If it is too high you may be drawing attic air into the Return air.
Just a guess as the result of field experiences.
Put reflective shades on those windows & awnings!
A 2.5-Ton ought to do better than that on 1200 sq.ft, even with 100 plus temperatures. I cool with ease over 900 sq ft old 1936 home with a lot of windows on the East, West & South, with a 6,000-btuh/half-ton Room A/C with arouind 100-F temps & 104-F heat indices. (Ductwork, ductwork, airflow, airflow!)
http://www.udarrell.com/airconditioner_current_temperature_btuh_charting.h tml
- udarrell
Man, you got hacked!
The duct insulation looks like crap. The suction line is missing about 2-3 ft. of rubitex insulation.
No inspection I presume...
Correct presumption.
Originally posted by pecmsg
Is this all new, Equipment and ducts?
I don’t have that model install manual here but I still think you need 36” of duct coming off that unit. Someone from RUUD can confirm.
I love the location of the A/H. My knees & back ache thinking about getting to it. Could they put it a little further back?
Suction line in the attic missing armor-flex, and from the pictures what’s there is too large.
Cover the line set, extend the drain, cover LV wiring. The list goes on & on
I will say I do like the use of round pipe instead of flex, but there not done yet.
Please tell me they haven’t been paid in full.
Yes, I believe it's new as date codes have it manufactured in 1/06 for the AH and 2/06 for the Condensing Unit and I saw it all in boxes before installation.
As for the location, I think that it's in the best place possible...yes tough to get to, but no good alternatives.
Will insulating the lines help with cooling? If so, I'll do it immediately.
Yes, paid in full.
Again, thanks a million for all the input guys. Being only vaugely familiar with AC/Heating equipment, I didn't know exactly what to look for on the install. At this point I think I need to get another contractor out to inspect the system and perform a load test.
edward301
09-09-2006, 05:33 PM
I just put a unit in a week ago just like your's, but
was a 3 ton unit.
Your duct work comming off the unit is too small. I
can not tell much about your return duct work.
That is a 13 seer unit. The one I put in is working
great, in 100 degree weather, pulls down to 74 in no
time, and keeps it there. Averages 3 cycles per
hour.
Gunnery Sergeant Hartman
09-09-2006, 07:04 PM
Originally posted by 4x4
Man, you got hacked!
The duct insulation looks like crap. The suction line is missing about 2-3 ft. of rubitex insulation.
No inspection I presume...
Correct presumption.
Originally posted by pecmsg
Is this all new, Equipment and ducts?
I don’t have that model install manual here but I still think you need 36” of duct coming off that unit. Someone from RUUD can confirm.
I love the location of the A/H. My knees & back ache thinking about getting to it. Could they put it a little further back?
Suction line in the attic missing armor-flex, and from the pictures what’s there is too large.
Cover the line set, extend the drain, cover LV wiring. The list goes on & on
I will say I do like the use of round pipe instead of flex, but there not done yet.
Please tell me they haven’t been paid in full.
Yes, I believe it's new as date codes have it manufactured in 1/06 for the AH and 2/06 for the Condensing Unit and I saw it all in boxes before installation.
As for the location, I think that it's in the best place possible...yes tough to get to, but no good alternatives.
Will insulating the lines help with cooling? If so, I'll do it immediately.
Yes, paid in full.
Again, thanks a million for all the input guys. Being only vaugely familiar with AC/Heating equipment, I didn't know exactly what to look for on the install. At this point I think I need to get another contractor out to inspect the system and perform a load test.
Why don't you call the original installer and have him fix the job?
Was this a "side job"?
Something is fishiy about this job...
captainrat
09-09-2006, 07:21 PM
Oh My god! thats bad
cw0682
09-09-2006, 07:40 PM
But, WHY IN THE WORLD IS THAT RETURN PLENUM NOT INSULATED IN AN ATTIC. I agree with Darrel your drawing hot R/A and it will prolly help with your problem I doubt it will solve your problem. I guess that R/A plenum could be lined but I doubt someone would line duct in a resi application.
Hope this helps.
cw0682
09-09-2006, 07:44 PM
No I have changed my mind insulate that R/a Plenum and I bet it will help 100%. That return air could be getting as hot as the attic.
Originally posted by edward301
I just put a unit in a week ago just like your's, but
was a 3 ton unit.
Your duct work comming off the unit is too small. I
can not tell much about your return duct work.
That is a 13 seer unit. The one I put in is working
great, in 100 degree weather, pulls down to 74 in no
time, and keeps it there. Averages 3 cycles per
hour.
Here's a pic of the return duct, it's 20x20.
http://i2.photobucket.com/albums/y41/jimsimm/IMG_4983.jpg
Why don't you call the original installer and have him fix the job?
Was this a "side job"?
Something is fishiy about this job...
He's been back more times than I can count and even called in a fellow HVAC guy (#2) as a consultant. In fact it was #2 who told him I need more insulation, window treatments, etc. Unfortunately I wasn't at the house the day #2 came by.
OK, here's the whole story. The contractor has been licensed for over 25 years and primarily works for a huge company as one of their HVAC techs. As I'm new to the area (was actually living a couple hundred miles away when the equipment was installed), he was referred by several neighbors. Since I was an absentee owner and he is a neighbor, I felt I could trust him inside my house while I wasn't around, that way he could do the work on his own schedule. Based on many conversations, he said he's always done a very brisk business on his own time, so I had no reason to doubt his abilities. Understand, since he's a neighbor, I feel I'm in somewhat of a sensitive position as it stands right now.
Originally posted by cw0682
No I have changed my mind insulate that R/a Plenum and I bet it will help 100%. That return air could be getting as hot as the attic.
Hey cw0682, I was typing a reply and getting the pic in order when you responded.
The RA plenum is indeed lined on the inside. Also, I haven't felt it while the unit is running to know whether or not it feels cold or cool up in the attic, but will. Thanks for the input.
cw0682
09-09-2006, 08:01 PM
Well with it being lined and i don't see evidence of tacks on your newest pic, I would definetly be interested to look in the return and make sure the liner hasn't came loose and that the liner is in fact one inch. Deffinetly take a temp right there as it goes in the air handler.
hvacmike33
09-09-2006, 08:23 PM
Hope you guys dont mind me adding to chat. I'm not crazy about the duct work having a tee like that! Its like water and will take the path of least resistance! I hope there is some kind of turning vane in there! That suction line needs to be insulated or you could get some water spots on your ceiling. I'm from the midwest so we dont have your kind of temps, however it still gets dang hot in the attics. I have installed a lot of units in attics and we don't have any problems! I don't know your entire situation, but it sounds like the size of the system is close! If I had to speculate, I would say you have mechanical issues! I would be curious to know what kind of pressures you are running on the condenser! Also find out what your drop is across your coil. Does that system have a fixed orfice metering device or a txv? Anyways thanks for let me join in!
hvacmike33
09-09-2006, 08:36 PM
For got to add one thing, you need to put on a float switch or add a secondary drain!!!!!!!!!!! after you get it working right.
Originally posted by hvacmike33
Hope you guys dont mind me adding to chat. I'm not crazy about the duct work having a tee like that! Its like water and will take the path of least resistance! I hope there is some kind of turning vane in there! That suction line needs to be insulated or you could get some water spots on your ceiling. I'm from the midwest so we dont have your kind of temps, however it still gets dang hot in the attics. I have installed a lot of units in attics and we don't have any problems! I don't know your entire situation, but it sounds like the size of the system is close! If I had to speculate, I would say you have mechanical issues! I would be curious to know what kind of pressures you are running on the condenser! Also find out what your drop is across your coil. Does that system have a fixed orfice metering device or a txv? Anyways thanks for let me join in!
Hey Mike, I don't mind at all...the more ideas the better as far as I'm concerned.
I don't know too much about pressures, but my contractor did say #2 told him to take one up from 70 something to 85. I also seem to remember something around 280. I presume we're talking low and high pressures, but again I'm lost with respect to this topic. Contractor said TXV.
Gunnery Sergeant Hartman
09-09-2006, 08:51 PM
Hire in a reputable contractor and go with his recomendations.
Ask for a load calc and a guarantee of satisfaction.
You hired a hack and got that exact type of work.
There is nothing more that you can do except break open that wallet and get ready.
Looks like there is a secondary pan under the unit. The p-trap is installed backwards with no vent. I guess the installer forgot that crap flows downhill.
This is a very poor install. Looks to me like you need to get a competent company to fix this install.
As far as sizing goes manual J is the only way. I will say that I cool my 1700 sqft house, built in the 50's with a 2.5 ton unit. I could keep the house at 73F when it was 102F outside. It is also a 13 SEER unit.
On behalf of the entire professional HVAC industry about all I can do is offer an apology for such poor work. This is one reason why I left residential for commercial.
Bill R.
Originally posted by hvacmike33
For got to add one thing, you need to put on a float switch or add a secondary drain!!!!!!!!!!! after you get it working right.
4x4,
I suspect 30%+ duct leakage with possible return air pulling air from the attic. In addition, you could have refrigerant leve, non-condensibles, and air flow issues.
Can you provide return wet-bulb, dry bulb, suction/liquid psi's, etc?
edward301
09-09-2006, 11:02 PM
Metal roofs produce very hot attics. I would insulate
the return duct, even if it is internally insulated, plus
would seal the joints more on the return ducts.
I do not know if the unit is charged properly, but I
do know your supply ducts leaving the air handler are
not big enough.
Also verify the fan speed is on max, with such a small
supply duct, you need all the air speed you can get.
With that size air handler, it will not produce too
much air flow.
tinner73
09-10-2006, 07:39 AM
i hate to state the obvious but there appears to be a "poke" damper in the y-branch that comes off the unit. make sure it's adjusted properly.
rlj1117
09-11-2006, 01:01 PM
looks like shotty install, 1st trap on condensate line is backwards, insulation not sealed,not to say thats the whole problem but alot of small items can surely affect performance, also ruud systems have to have copper lines sized properly to perform correct.
rlj1117
09-11-2006, 03:54 PM
one more thing looks like several problems,need to make sure evaporator coil is installed correct,it will physically fit both ways ,but only one way is correct.i have seen this problem numerous times
precise temperatures
09-13-2006, 01:18 AM
The unit has a TXV, you can see the bulb wrapped in rubatex at the outlet of the suction line from the unit.
Sorry, but I am not buying the story of this "guy" who has been doing this 25+ years putting this in for you. Something is just not adding up.
First off, the way the p trap is installed is suspect right there to a HODIY'er. For those of you who don't know, a "Home Owner Do It Yourselfer". I do not believe that someone who has been doing this for 25+ years would install a trap like that. No way. Just by looking at it you can tell the condensate will overflow. Plus no vent tee.
2nd thing, it doesn't make sense that you would not want him to come back to fix it. You stated earlier that you paid good money for this. Why would you just let him off the hook? Oh yeah, thats right....he's your neighbor. :wink,wink: Whatever.
3rd thing and it should be the most stand out thing is that the unit could not even have been running. Thats right, not running. And you know how I know that???? Look at the emergency pan, you can see finger prints in that pan. With a p-trap that will not drain the condensate will have to go somewhere. Likely one of two places, emergency pan or ceiling. Looks like neither to me. And if you had this "guy" out to your house 10 times along with the mysterious "#2 guy" and they couldn't figure out the unit wasn't even running??? Gee, let's see, I have a 0 degree split....87 in, 87 out....let's seal some ducts, that will fix it....COME ON NOW!!!!
What I see here is a HODIY'er that went bad. The proudness sat in when it was all done and ready to turn on. Wifey was real proud. Only 4 hours later you realize its not cooling down in here. "Let me check it out" you say to yourself with that nervous feeling in your gut. Oh crap you say, I don't know what to do, let me get on hvac-talk forum and get expert advice from the pros and save even MORE money on my shoudy install.
Thats what I think happened!!!!
If I am wrong then I apologize, but my gut feeling tells me otherwise.
[Edited by precise temperatures on 09-13-2006 at 01:46 AM]
AIR PRO
09-13-2006, 01:59 AM
Hell, where do I start.. First of all that looks to me like a UHSA Ruud air handler(13 seer), so the supply duct requirements of the UBHC/UBHK are not the problem here. I see cadoprene(sp?) on the return which tells me this was a contractor doing this job(unless of course the HO has a relative that is one, and told him to use it).As said above, the P-trap is backwards, no armaflex on the suction line, etc... = a VERY POOR INSTALL.
I also agree with the others that you should have went with the contractor that did the load calculation. That supply connection looks like a problem within itself! HIDEOUS!
lynn comstock
09-13-2006, 06:10 AM
Then it gets frustrating for techs and homeowners alike.
The P trap error is a beginner's error. I almost think that it is a DIY job. But most of what I see looks kind of average for the trade. (Average does not equal good.)
Based on the homeowner’s description of the home's construction, I am comfortable with the equipment sizing. I don't think we can do more than guess and speculate about air leakage, gas charge, non-condensable, duct sizing and duct design issues and other critical issues.
What we need here is more information.
4x4 This is what you need to find your way out of the possibilities: Find a tech who will agree to measure the duct static pressures and collect the information that you request. This requirement, alone, will eliminate a lot of Bubbas. If the tech doesn't know what the problem is, no matter. What we need here is more, reliable, information.
*********************************************
Model number and Serial number of outdoor unit.
Model number and Serial number of indoor unit.
Expansion device (capillary tube, orifice, or Thermostatic Expansion Valve (TXV))
Refrigerant (R-22) yes?
********************************************
Data needed after 10 minutes of continuous operation:
Outdoor temperature of air entering the outdoor coil.
Outdoor temperature of air leaving the outdoor coil.
Return air temperature of air at the Return Air grille.
Return air Wet Bulb temperature of air measured at the Return Air grille.
Return air temperature (entering the air handler).
Supply air temperature (leaving the air handler).
Supply air temperature (leaving a mid distant supply grille)
Head pressure.
Liquid line temperature near the OD coil.
Suction pressure.
Suction line temp measured near the indoor coil.
Suction line temp measured near the compressor.
Feeling the bottom of the compressor immediately after compressor stops a run cycle is (too hot to hold your hand on, warm, cool, cold).
******************************************
a. Duct supply static pressure measured at the air handler.
b. Duct return static pressure measured at the air handler.
c. Total duct static pressure measured should equal a+b.
d. Static pressure difference measured across the indoor coil.
e. Static pressure difference measured between the furnace and the A coil (If this is what you have).
******************************************
Collecting this information takes about an hour. It is in the homeowner's interest to witness the data collection as much as possible.
Originally posted by precise temperatures
The unit has a TXV, you can see the bulb wrapped in rubatex at the outlet of the suction line from the unit.
Sorry, but I am not buying the story of this "guy" who has been doing this 25+ years putting this in for you. Something is just not adding up.
First off, the way the p trap is installed is suspect right there to a HODIY'er. For those of you who don't know, a "Home Owner Do It Yourselfer". I do not believe that someone who has been doing this for 25+ years would install a trap like that. No way. Just by looking at it you can tell the condensate will overflow. Plus no vent tee.
2nd thing, it doesn't make sense that you would not want him to come back to fix it. You stated earlier that you paid good money for this. Why would you just let him off the hook? Oh yeah, thats right....he's your neighbor. :wink,wink: Whatever.
3rd thing and it should be the most stand out thing is that the unit could not even have been running. Thats right, not running. And you know how I know that???? Look at the emergency pan, you can see finger prints in that pan. With a p-trap that will not drain the condensate will have to go somewhere. Likely one of two places, emergency pan or ceiling. Looks like neither to me. And if you had this "guy" out to your house 10 times along with the mysterious "#2 guy" and they couldn't figure out the unit wasn't even running??? Gee, let's see, I have a 0 degree split....87 in, 87 out....let's seal some ducts, that will fix it....COME ON NOW!!!!
What I see here is a HODIY'er that went bad. The proudness sat in when it was all done and ready to turn on. Wifey was real proud. Only 4 hours later you realize its not cooling down in here. "Let me check it out" you say to yourself with that nervous feeling in your gut. Oh crap you say, I don't know what to do, let me get on hvac-talk forum and get expert advice from the pros and save even MORE money on my shoudy install.
Thats what I think happened!!!!
If I am wrong then I apologize, but my gut feeling tells me otherwise.
[Edited by precise temperatures on 09-13-2006 at 01:46 AM]
Apology accepted, but if you're still convinced that I did the job myself, I'd be happy to give you the guy's name and phone number, please email me at lynnie123@earthlink.net (there's a strong spam filter installed so please put some sort of identifying language in the subject line).
FWIW, I've taken all the replies, comments and suggestions that I've gotten from this board and printed them. I intend to give them to the contractor, so thank you all for your concerns, ideas, opinions and suggestions. These are coming straight from his peers so I don't believe he can get terribly upset with me. In fact if anyone has a reason to be upset it's me as I'm out many greenbacks and have a system that is marginally useful (actually the 100 degree temps broke here this week and now the system is performing much better...it cycles nicely at 77 during the late evening and night now).
leapfrog
09-14-2006, 05:05 PM
One more time with feeling!
YOU NEED TO GET A MANUAL J HEAT GAIN CALCULATION DONE, FOLLOWED BY A MANUAL S TO SELECT THE SYSTEM AND A MANUAL D TO DESIGN THE DUCT WORK.
Anything else is just guessing at system sizing and the duct work. And a pretty good indication of a hack.
http://www.fsec.ucf.edu/bldg/pubs/ACsize/index.htm
Originally posted by leapfrog
One more time with feeling!
YOU NEED TO GET A MANUAL J HEAT GAIN CALCULATION DONE, FOLLOWED BY A MANUAL S TO SELECT THE SYSTEM AND A MANUAL D TO DESIGN THE DUCT WORK.
Anything else is just guessing at system sizing and the duct work. And a pretty good indication of a hack.
http://www.fsec.ucf.edu/bldg/pubs/ACsize/index.htm
Agreed, but my plan calls for confronting the contractor with all this new information. What I'm going to propose is I'll pay for an inspection/calculation from a "reputable" local contractor and ask that my original contractor comply to the recommendations. I realize he doesn't have to since he's been paid, but I'm hoping he'll realize how badly the system is designed and installed....the p-trap thing is very disturbing (I didn't pay much attention, but now that you guys pointed it out, I don't think that I could make that mistake if I were to have installed it).
leapfrog
09-14-2006, 05:27 PM
You might be better served by having the original installer do the heat gain and duct design calculations, while you do a heat gain calculation of your own (click on the HVAC Calc link at the top of the page). You should come up with the same heat load (in BTU). If his numbers differ significantly from yours (i.e. by more than .3 ton or so) then you can sit down with him and reconcile the input information.
He may learn something in the process.
grasshopper1
09-14-2006, 06:47 PM
wow thats bad it hurts my eyes just to look at it.
lynn comstock
09-14-2006, 09:32 PM
I believe that something else is creating your problem. Your contractor should at least collect the data for us to look at.
Obviously a heat load is a good idea. The New International Resiential Code (and other codes) REQUIRE a manual J heat load. Enforcement is another matter.
Originally posted by precise temperatures
3rd thing and it should be the most stand out thing is that the unit could not even have been running. Thats right, not running. And you know how I know that???? Look at the emergency pan, you can see finger prints in that pan. With a p-trap that will not drain the condensate will have to go somewhere. Likely one of two places, emergency pan or ceiling. Looks like neither to me. And if you had this "guy" out to your house 10 times along with the mysterious "#2 guy" and they couldn't figure out the unit wasn't even running??? Gee, let's see, I have a 0 degree split....87 in, 87 out....let's seal some ducts, that will fix it....COME ON NOW!!!!
Just for my #1 fan:
http://i2.photobucket.com/albums/y41/jimsimm/IMG_4996.jpg
http://i2.photobucket.com/albums/y41/jimsimm/IMG_4997.jpg
....and no the lovely wife was not up in the attic pouring a bottle of water down the pvc pipe......
Really sorry 4*4, dont know what to say, I still have trouble sleeping at night before the job making sure measurements are ok, silly I guess. Christ is that the right line set looks used, the thing looks like it has to be kinked by the pad!
Originally posted by vlux
Really sorry 4*4, dont know what to say, I still have trouble sleeping at night before the job making sure measurements are ok, silly I guess. Christ is that the right line set looks used, the thing looks like it has to be kinked by the pad!
...not sure if it's right or not, I would hope it is. Also, I've never noticed any kinks, but will inspect more closely.
docholiday
09-18-2006, 04:16 PM
I think it's best you contact a reputable company and not the one this guy works for. If he's your friend, you dont want him to lose his job when they find out he did a side job.
Have the ducting, piping, drain and overall installation evaluated and corrected. Let your buddy know you are disapointed to say the least and would appriciate some help in the costs you are about to face. Own up to the fact that you will probably spend more between this job and the corrections than you would have had you not gone the side job route.
Before you do any of that, download and buy a copy of hvac calc (see a link from this site) and decide if it's not best to scrap the whole job and start over if the unit is way off size.
Sorry this happened to you but odds are you are going to be continually dealing with issues as long as this guy is involved in it. Also, do your friends a favor when they mention getting someone to do a side job for them and tell them your story.
obxtech
09-18-2006, 11:26 PM
Im speachless.....
AIR PRO
09-21-2006, 12:46 AM
So, what was the outcome of all this?
Still pending....stay tuned as I'll keep everyone updated.
Ok, time for a follow-up.
The contractor came out today at my request and I gave him a copy of this transcript, photos and all.
As you can imagine, he was pretty shocked, but that goes without saying. Anyway, his response to the claims that the duct coming from the AH is too short was that there are two turning vanes within the ductwork that compensate for the small size. He did agree that the Return Air portion of the system needs to be externally insulated even though there is internal insulation. As for the p-trap, he said direction doesn't matter so long as the water makes it to the outside....personally I don't see the need for a trap. He also said the exposed line needs insulation.
He took a copy of these Q's & A's with him and plans to show the dialog and pictures to some of his peers (including a guy who works for Ruud) to get their ideas and opinions. He also mentioned something about doing a Manual J calculation. Finally, he asked me to ask you guys if a 20x20 return grill is large enough for the system and house size in question. He suspects that it could/should be larger.
AIR PRO
09-28-2006, 01:16 AM
"As for the p-trap, he said direction doesn't matter so long as the water makes it to the outside....personally I don't see the need for a trap"
I have a feeling he was only telling you what you wanted to hear. If he asked you to ask us whether a 20X20 return was okay......come on!
coolmen
09-28-2006, 10:06 AM
this is my preferred equipment,Im installing this brand all the time.The supply openning is 16 x 10.5 To reduce it to connect to the main trunk looks wrong.(choke)What did they reduce it to ?? its ok to do this when i know im pushing 800 cfm or less 16 x 10 to 14 x 10. I would have come off the duct at least 3 ft with 16 x 10 before teeing off the main.The return if not insulated "IS" a huge problem. To introduce attic heat into the cooling load or system is just like leaving the blower door open or filter door to allow attic heat into the system. quick fix insulate return and possibly check fan speed setting.yes insulate the copper suction line.this just adds to the problem.
Coolmen, so the turning vanes aren't relevant and don't compensate for the undersized duct?
Hawk327, seriously. The consultant he brought out, who's supposed to be one of Ruud's top installers in the country (at least according to my guy), told him that 20x20 is proper size, but my tech has always had a doubt. I've told him that my other house is 2,200 SF and only has a 16x25 (this after I enlarged the opening many years ago subsequent to my purchase) return air grill and I've never had any problems
[Edited by 4x4 on 09-28-2006 at 04:31 PM]
coolmen
09-28-2006, 04:36 PM
undersized is undersized no matter how you look at it.But how much undersized remains to be seen. If its written some where that turning vanes will solve a under sized duct problem. I havent seen it.what are the size of the duct you have. just curious
Originally posted by coolmen
undersized is undersized no matter how you look at it.But how much undersized remains to be seen. If its written some where that turning vanes will solve a under sized duct problem. I havent seen it.what are the size of the duct you have. just curious
His argument was that without the vanes the forced air wouldn't go anywhere, i.e. just linger around the "T" area, but with the vanes the air flowed smoothly down the trunk duct and then on to the individual room ducts.
To answer your question, I honestly don't know because I've never measured. I'll head up there this evening with my tape....
xersw
09-28-2006, 05:20 PM
Im a rheem king dude heres your problem first of all thats a thirteen seer not only is it a 13 seer but its the longer blower,rheem got so many complaints about that blower that they started to make the 13 seer in the rheem classic.If it was a 14 seer we could mess with some dipswitches and accomadate for that duct system.If the unit is sized accordingly to sq ft,taken windows,insulation,the side of the house is facing ex.north,south etc.etc.heat load etc.etc.That duct i will tell you this is not sized accordingly period period ...end of story.If you need some help write.
what are the size of the duct you have. just curious [/B]
The duct coming directly off the AH is 20" long by 14" high by 18" wide.
The big rectangular trunk duct is 14" wide by 12" high by ~30' long.
udarrell
09-28-2006, 09:27 PM
Originally posted by 4x4
Ok, time for a follow-up.
Clipped...
He took a copy of these Q's & A's with him and plans to show the dialog and pictures to some of his peers (including a guy who works for Ruud) to get their ideas and opinions. He also mentioned something about doing a Manual J calculation. Finally, "he asked me to ask you guys if a 20x20 return grill is large enough for the system and house size in question. He suspects that it could/should be larger."
"If" that is a Return air Filter Grille Rack I would go to a 25X20 to get somewhere near 350-FPM face velocity. Then you have to consider the "free air area of the specific filter that is being used, as there will be less free air area with the filter installed, therefore the installed clean filter face velocity will again be increased!
At 350-FPM the 20X25 without a filter would ballpark deliver 1215-CFM, with the filter installed it could be around the required 1000-CFM of Return Air; those are only rough guestimates, I have NO idea what the duct system static pressures are, etc.! - udarrell
Powered by vBulletin® Version 4.2.0 Copyright © 2013 vBulletin Solutions, Inc. All rights reserved.