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Old 09-24-2009, 02:41 PM   #16
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I think something is wrong...


Here are todays results.

Outside Temp.= 84
Inside Temp= 74
Indoor WB= 65
High Side= 190
Low Side= 78
Suction Temp= 43
Liquid Temp= 80
Return Air= 74
Supply Air= 63

With only one zone calling and bypass damper being used:

High Side= 190
Low Side= 75
Suction Temp= 40
Liquid Temp= 81
Return Air= 74
Supply Air= 63

98 degree temp air coming from outside condenser. A couple of notes to add, there is a deck 8.5 feet above the condenser, when measuring outside air away from condenser it was 78 degrees. I know this can't be good but would it result in the low suction temps? Lastly when it was in heat mode it did fluctuate those 10 degree swings on a regular basis and that was with the TXV attached. Could it be 2 problems I have??

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Old 09-24-2009, 05:40 PM   #17
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I think something is wrong...


As far as the heat goes the indoor TXV should be bypassed when in heat mode. Sounds like outdoor unit cycling off on high pressure.

Cooling you said the evaporator coil was changed this winter. Has this problem just started or been all this cooling season?

With a 43 suction and only 11 temp drop it seems as if some airflow is bypassing evaporator coil.
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Old 09-24-2009, 06:00 PM   #18
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I think something is wrong...


Evaporator was changed out because it was discovered that it was the incorrect coil. We don't usually use the AC in the summer because we live in a high elevation and use a whole house fan at night to bring in cool air. I'm preparing for winter because it does get cold here. Would the heat fluctuate like that because of noncondensibles? Here are the pictures of the returns to the heat pump. The plenum has 2 filter grills attached and is 20x12 in dimension. This is why the 14x14 filter grill was added.

I think something is wrong...-p1040315.jpg
I think something is wrong...-p1040316.jpg
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Old 09-24-2009, 06:17 PM   #19
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I think something is wrong...


If non-condensables in system the pressure would fluctuate up and down.

Low suction line temp and low temp diff in cooling is what is concerning.

If air is by-passing coil and not enough air getting through, in heat mode your high pressure will build up fast, tripping HP switch and shutting down compressor.

Check preesures in heat mode. If they run up to 300 quickly, pull bottom A/H panel off and see it there is a way air is getting around coil. Ruud?Rheem fit pretty tight if installed properly. Is coil all the way in against back of unit, is coil level ect. Use a light above the coil and look through the return below the unit to locate any gaps.

In the coil replacement kit there should have been a 1" thick gasket that goes on the front of the drain pan as an air seal against the bottom panel.

Last edited by KAVF; 09-24-2009 at 07:22 PM.
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Old 09-24-2009, 09:41 PM   #20
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I think something is wrong...


Here are a couple of pics looking into return plenum from basement and under the air handler looking up at the evaperator coil.

I think something is wrong...-p1040320.jpg

I think something is wrong...-p1040319.jpg

I think something is wrong...-p1040318.jpg
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Old 09-25-2009, 07:58 AM   #21
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I think something is wrong...


Quote:
Sounds like outdoor unit cycling off on high pressure.
You were right. Could there be any chance that the system is overcharged causing all of these symptoms? The coil looks pretty tight as far as air flow. The AC pressures are much better that heat mode which relies on fixed orifice to meter refrigerant. The pressure is heat mode skyrocketed which made me yank the breaker out immediately.
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Old 09-25-2009, 07:48 PM   #22
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It maybe overcharged some but the 63deg supply temp is what is bugging me. With a 41 suction temp your supply air should be in the 40s to low 50s. It is like the return air temp is mixing with the air that is going through the coil.

Did you check for that gasket on the front of the drain pan I mentioned?
Test with light above coil and looking from return opening?

If the coil was replaced within a year is the work still under warranty? You may want to get them back out.
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Old 09-25-2009, 08:36 PM   #23
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I think something is wrong...


Is the A/H in the basement? and the condensing unit/ hp above? I don't see a trap, and wonder if it is possible that the oil is collecting in the evaporator? The 11 degree TD is weird and the there should be a considerable difference when the bulb is submerged in ice. If system was overcharged, wouldn't you see a significant higher pressure on the liquid line?
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Old 09-25-2009, 08:59 PM   #24
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Just noticing something wrong with the last picture.

On the right side there is some bare copper tubing showing (no fins) This maybe where some of the air is by-passing the coil.

Trying to remember, Ruud/Rheem back end plates. I remeber seeing little half moon wedges that go under the end passes and hold the end plates on tight to the fins. Seems like this "New" coil maybe missing these.

Maybe someone who deals with Ruud/Rheem knows more about this.

At any rate it seems this coil is deffective.

Last edited by KAVF; 09-25-2009 at 09:15 PM.
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Old 09-25-2009, 11:16 PM   #25
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I think something is wrong...


I looked for the gasket you mentioned and what I found was a foam gasket on the left and right side. The back of the coil is up against the back insulation of the cabinet and the front of the coil is also against the panel with insulation. The copper tubes you saw were beause the thin sheet metal was not pushed up tight to the coil, perhaps missing those wedges you talked about. It does look like a very small area for some air to get through. I guess what baffles me is in cooling mode the pressures are not way off but the supply air is off but in heat mode the pressures sky rocket immediatlely putting the compressor in harms way! That why I was wondering if the metering devices could be affecting this. What if the system was grossly overcharged?? There is a receiver and suction line accumulator on this unit, would these affect the pressures and temps with txv versus fixed orifice?
By the way the basement and the outdoor unit is on the same level.
Here is the charging chart on condenser.
I think something is wrong...-p1040263.jpg
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Old 09-26-2009, 06:21 AM   #26
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I think something is wrong...


It could be overcharged to get suction pressure up.

Air is lazy and will take the least path of resistance. Those gaps don't look that big, but it is amazing how much air will go around there.

In the heat mode that air going around will not remove the heat from the coil as well, thus causing pressures to climb fast. (like having the blower door off)

Either get the end plates to seat right or replace the coil (should be under warranty) then get the charge correct.
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Old 09-26-2009, 06:17 PM   #27
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Well I had a tech friend who works for a local company come out today to check out the system. He is skilled and has worked for this company for years. He looked over the air handler and said he didn't feel that the air flow was my problem although it is not perfect. He then went out to the condenser and used a scale and recovered my refrigerant. The proper amount for my heat pump is 12lbs plus line set, 13 total. He pulled out 22lbs!!! Talk about overcharged!!! He said the pressures on his manifold were in the single digits so he stopped recovering. Then after removing pump and tank he was surprised that the pressures rose to 30 psig. Then he charged system back with 13lbs of refrigerant. When he looked at the pressures in cooling mode he seemed happy with them and inside supply air went to 59 degrees. I asked him before he went if we could put it in heat mode to check pressures knowing that it was a fixed orifice and not txv metered that way. He did so and he waited for the heat pump to come on. When the unit came on the High side pressure went through the roof almost immediately!!! It made it as high as 475psig. before he shut it down.
He feels that it may be the TXV but is going to ask his boss and get back to me. Since there was still pressure showing when he was recovering the refrigerant could it still be way overcharged causing pressure to skyrocket only in heat mode through the fixed orifice? Could TXV have this effect in heat mode when it is supposed to be metered by orifice? Why do we only get high pressures in heat mode?? Your continued help is appreciated.

Last edited by carlb7; 09-27-2009 at 08:53 AM.
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Old 09-27-2009, 08:20 PM   #28
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I think something is wrong...


To eliminate air flow as the culprit,run system on emergency heat. The td should be about 50 degrees without the elements tripping on high temp. If the elements are tripping, then there is likely an air flow issue.

I would be concerned that the system was evacuated down to single digits, then pressure rises to 30 within minutes. Sounds as if there is some sort of restriction. Perhaps the txv, perhaps the movement of the Reversing valve, maybe even the fixed orifice is incorrect. This one is a doozey. Looking forward to hearing the outcome.

I don't intend this as a personal question, but, you seem quite involved with this problem and you are bringing in your friend. Did you install the system? Most people would immediately go to the hvac company that did the work as this seems to be a warranty issue. Many outfits will wash their hands of this situation as soon as someone else touches it.
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Old 09-28-2009, 06:19 AM   #29
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I think something is wrong...


Thanks Flashheatingand. I will do the test you mentioned. I have been "through the mill" with constant problems with this heat pump from day one. The original contractor was unable to fix it after many attemps. I've had condenser coil replaced, return grill enlarged, bypass duct added, filter dryer installed for the first time, filter dryer replaced after restriction found, evaporator coil replaced when I discovered it was a mismatch. I may have missed something I don't know. Through all this I have educated myself so I would not be given bad information on what was wrong. My friend is helping me as a side job but he works for a local company. I have had a few contractors come out when the original gave up no one could ever solve the problem. I even posted a video on UTube for help!
Here it is:


That was last winter. I have since added another air return for more air flow. I'm hoping this years problem may just be a TXV gone bad. I just want it to work this year and not cost me a small fortune to run, There you have it, my sad story.

Update: I did the emergency heat mode and checked Delta Temp. 74 Return Air and 115 Supply Air= 41.

Last edited by carlb7; 09-28-2009 at 07:54 AM.
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Old 09-30-2009, 11:23 AM   #30
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I think something is wrong...


After removing a ton of refrigerant the pressures are now where they are supposed to be in heating mode on the Manf. chart. Here is my uneducated guess on what might of took place here. The TXV is bad. When charging system in cooling mode the pressures never came up and the refrigerant kept being added. Ten pounds extra and the pressures never came up! Went into heat mode, now metering with the fixed orifice, pressures are through the roof. Recover refrigerant until pressures come down and now its working well and making heat! Does this make any sense or am I way off here.

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