New Install Questions

[mikeinva]

Recently had my 18 year old Ruud condensing unit,Apollo hydroheat air handler and attic duct work replaced. The Air handler was rusting away, the pan was almost full of water and the duct was falling apart and it was the cheap gray plastic stuff with next to no insulation. The plenum on the air handler was about a foot long pyramid shape that had 5 ducts for 2 baths and 3 bedrooms and a 10inch duct that ran to the other end of the attic that fed 4 more ducts. There was some serious leaking going on. As bad as it looked the house stayed cool and comfortable!!

My home is 1100 square feet and located near Va Beach Virginia.

New unit is a 2 Ton Ruud 10Seer condensor and Apollo SA3024 air handler in the attic. The new duct is silver faced R6. The return is 14 inch with 14X30 merv8 filtrete filter located in center of the house hallway. The 12 foot air handler plenum feeds 9ea 6 inch ducts. 2 ducts are reduced to 3 inch for bathrooms. The duct liners are silver taped ( the expensive very sticky type) to the register collars and tie-wrapped and the insulation is then taped and tie wrapped. There is NO obvious leakage of air anywhere. The plenum is 12 feet long and fabricated from 1 1/2" Owens Corning Enduragold Ductboard.

The installer evacuated the system for approximately 30 minutes with a pump that had no gauge?? He also added no R22 to the factory charge.

Im concerned about the cycling times and air temps at the registers.

During the day using a laser thermometer I get about a 10-12 degree temp drop between the return air intake 72 and the register fed by the first duct on the plenum 60. The farthest register which is at the end of a 25 foot run has about a 7 degree difference at 65.

I feel a lot more air than before at all registers but seems like the temps should be lower??

My RH is running around 40% and there is a steady drip at my condensate line.

The high today was 85. Right now its 9:30 at night 76 outside with RH68 thermostat is set on 72 indoor RH is 35 and my unit is running about 10 minutes and then shutting down for 10-12. So far today the AC has run 8 1/2hrs out of 21.5 hrs

What do the pros think?? My biggest concern is that my register temps arent anywhere near 20 lower than my return intake temp?

[BaldLoonie]

You can't go totally by the register temps. Also check right over the air handler measuring the return as it enters and supply a few feet from the exit of the unit. That should be 15-20 degree difference. The 3024 runs around 800 CFM so should be moving the right amount of air for the 2 ton unit.

Not using a micron gauge isn't a good install. With a long line run, chances are some charge should have been added. But seems like the unit is keeping the place plenty cool and dry so hard to say. I would hope he used Ruud's charging chart and made sure the unit was right on the mark.

[dan sw fl]

Originally posted by mikeinva


1100 square feet
located near Va Beach Virginia.

New unit is a 2 Ton Ruud 10Seer condensor and Apollo SA3024 air handler in the attic.
new duct is silver faced R6
return is 14 inch with 14X30 merv8 filtrete filter located in center of the house hallway.

12 foot air handler plenum feeds 9ea 6 inch ducts
2 ducts are reduced to 3 inch for bathrooms
duct liners are silver taped ( the expensive very sticky type) to the register collars and tie-wrapped and the insulation is then taped and tie wrapped.

There is NO obvious leakage of air anywhere.

The plenum is 12 feet long and fabricated from 1 1/2" Owens Corning Enduragold Ductboard.

The installer evacuated the system for approximately 30 minutes with a pump that had no gauge??


He also added no R22 to the factory charge.


Im concerned about the cycling times and air temps at the registers.

During the day using a laser thermometer I get about a 10-12 degree temp drop between the return air intake 72 and the register fed by the first duct on the plenum 60. The farthest register which is at the end of a 25 foot run has about a 7 degree difference at 65.

RH is running around 40%
there is a steady drip at my condensate line.
high today was 85
its 9:30 at night 76 outside with RH68 thermostat is set on 72 indoor RH is 35

my unit is running about 10 minutes
then shutting down for 10-12.
So far today the AC has run 8 1/2hrs out of 21.5 hrs

What do the pros think??
My biggest concern is that my register temps arent anywhere near 20 lower than my return intake temp?

"Sounds like" a good install ...
but HOW can that be?

What is the diffuser outlet temprature measured with a conventional Temp gauge?

I don't know how you are getting AS LOW AS 35% R.H. with only 60'F ... delta T 12'F at the closest diffuser.

What are the current refrigerant conditions?

Was a Start-Up Report written valdiating the equipment performance, refrigerant charge and other parameters are ALL within specs ?
sssssssssssssss

[Irascible]

I'd add that you need to get a digital pocket thermometer. They're less than $20 and way more accurate than infrared in most cases. Infrared thermometers are OK trend tools under the right circumstances. But they're influenced in gross fashion by the emissivity of the item being measured and can therefore be extremely inaccurate. Unless you understand emissivity and are compensating accordingly, put the laser gun down and back away.

[Mr Bill]

Originally posted by Irascible
Infrared thermometers are OK trend tools under the right circumstances. But they're influenced in gross fashion by the emissivity of the item being measured and can therefore be extremely inaccurate.

0 but mine get my fried chicken oil just perfect at 350 degrees then I drop in the old bird for a perfect piece of chicken every time.

[a\c don]

Steady drip from condinsate drain line is a good thing.

40% RH is also good especially in a coastal area.

Get rid of that laser thermometer, they are very misleading in the way you are trying to use it.

[mikeinva]

How do I check temps at places suggested since the ductwork/plenum etc are closed??

The lineset run is maybe 20 feet.

Thermo still at 72. Now Im getting 57 at the farthest register from air handler and 55 at the closest!!! The attic temp is down to 75 from 100 today.

Could that silver faced R6 duct be heating up so much I can get no more than a 10 degree difference during the day?? What will happen when its 90-95 outside and the attic is even hotter?

I have 10 roof vents on the backside of my house. I have 13 soffit vents on the front of my house but have yet to install any vents in the new soffit on the rear of the house. Perhaps 10 soffit vents on the rear of the house would help the air flow and cool the attic some.

[mikeinva]

What makes me feel good is that nobody has suggested that the 2 ton unit is too big for my 1100 sqaure foot single story ranch that faces South West. Black roof, lots of glass and rear sliding doors but all Low E double pane. Well insulated attic.

[Irascible]

Two tons is WAAAY too big!

[Irascible]

Sorry about that. I couldn’t resist.

You drill little holes to check temperatures where there aren't any holes. Don't use those laser drills though. Very inaccurate.

The ducts can make a couple degrees difference sometimes. But you've got R-6 and... well, there's something fishy going on. That laser thermometer is probably the source of the fish. But in any event the contractor should be happy to check things out if you don't resolve this.

[mikeinva]

Ha Ha... So you dont really think 2 tons is way too big?? My run times started at 5 minutes this morning but each one was longer and longer as the outside temp rose. I left before the heat of the day but the last run time I measured was 25 minutes and like I said my RH is running 35-42.

I assume its normal not to run long when the thermo is set on 72 and its high 60's outside in the morning??

[mikeinva]

So drill small hole in return air plenum and supply plenum and stick thermometer in?? Check temp difference. I have several of the thermometers with about a 6 inch stem.

The return plenum is very short so I know where to drill the hole in that.

How far from airhandler should I drill the hole for supply air temp?? Should I also check temp near end of plenum?

Ha Ha again

[Irascible]

Originally posted by mikeinva
So drill small hole in return air plenum and supply plenum and stick thermometer in?

Well... yes. But you don't know how queasy I feel about the mere suggestion that a homeowner should take a drill to his HVAC system. If you screw something up don't call me!

A couple feet from the evaporator coil should be enough for the air to have mixed. Sometimes you have to check multiple spots to make sure you're not getting a bogus reading.

[mikeinva]

I will just be drilling about a 1/8 inch hole in the return and supply Plenum areas which is made from 1 1/2 inch Owens Corning duct board. When Im done I'LL cover the holes with some of that high dollar super sticky silver tape.

Sound ok??

This AM inside 72 and RH41. Condensation on windows...outside.

[Irascible]

No. Duct board sounds awful. Give me sheet metal or give me death.

Oh... You were asking about the hole. Yeah. It's sorite.

[mikeinva]

As directed I drilled tiny holes and placed a thermometer in the return plenum and the supply plenum.

Its 5:04 in the evening here in Va and Outside its 77 degrees and RH67

Inside its 72 degrees and RH37

The attic is just under 100 degrees. The return thermometer measures 72 degrees and the supply plenum thermometer placed 4 feet from the airhandler on a 12 ft plenum measures 55 degrees.

The register air closest to the airhandler is 56 degrees

The register air farthest(25 feet flex) from the air handler is 58 degrees.

My AC just ran for 20 minutes with very little dripping from condensate line. When it shutdown there was a small but steady stream of water coming from the condensate line and iside RH was still 37.

Sound ok???

[Irascible]

I'm in a dry climate. So the numbers for humid areas aren't completely second nature to me. But those numbers could all be normal. The temperature drop might be a little low. If you lived out here then I'd say that it was almost for certain. But that depends on airflow and how much humidity is being removed.

The final piece of the puzzle is the airflow. To know how much capacity your system is delivering you need to know the airflow. That plus your readings plus a measurement of latent capacity tells you how well your system is doing. I know of no easy way for you to check airflow. The simplest way to infer airflow is to use a magnahelic and blower performance chart. Got both of those? Know what they are? If so, then you're set. And if so, you'd qualify as a senior technician at some of my favorite hack shops.

[dan sw fl]

Originally posted by mikeinva
Its 5:04 in the evening here in Va and Outside its 77 degrees and RH67

Inside its 72 degrees and RH37

Sound ok???

Perfect to have ~ 17+ Delta T
B U T BEWARE
your HYGROmeter is reading >10% LOW.

R.H. is likely just >50%.




[Edited by dan sw fl on 06-06-2005 at 09:01 PM]

[mikeinva]

I just closed the ball valves on the hot water heater to make sure hot water isnt moving thru the heating coil while the AC is running.

It was 85 here today and my attic thermo read right at 100

[Chuck 999]

sounds like you might have air entering the return air from the attic, 100 degree air entering the system will definitly change your discharge temp. System not designed to be drawing unlimited amounts of high temp air from attic space.