THPRE

**SBKold** · 01-26-2013, 02:36 PM

Your return reading is inaccurate. Cant be that low. And how is that outdoor air filtered?

**THPRE** · 01-26-2013, 04:11 PM

The outside vent is a 6 inch. with a motor to open and close. As far as I know it has just a screen and a rain hat. I watched the tests and they were done with the indoor filter removed and the louver door loose but mostly closed. We ran all tests three times. I ofcourse do not know how accurate his equiptment is but they are certainly a reputable firm - and not the one who installed the system. One other fact is that when we were on the phone yesterday we disconnected a 16in. duct right at the plunum. The pressures and cycle rate did not change. So this was with no filter,the vent open,and the filter door open and the door to the room open. As well as having the duct off ot the plenum - If this is not enough air flow there would have to be something right in the air handler?

**beenthere** · 01-26-2013, 04:24 PM

The static neds to be aken with the air filer in. And the louvered door closed And the door is part of the PD drop the blower works against.

**THPRE** · 01-26-2013, 09:04 PM

Ok but if the system was wide open in the return and had a 16in. duct removed from the plenum and I was still watching 610psi to 400psi in under 1 minute cycles there must be a further prob;lem? I mean that with sstatic pressure minimal and cfm close to 2100 there should not be an air flow problem causing the 610 high side?

**SuperTech2010** · 01-26-2013, 10:14 PM

goodman has factory reps...sound like u need one, you need some real answers

**garyed** · 01-26-2013, 11:10 PM

If you have an airflow problem the 3/8" line should get very hot at 600 psi for any length of time. It sounds a lot like an overcharge condition or a liquid line restriction. Almost every Goodman 410A unit I've installed has been overcharged from the factory. I put in a 15 SEER 4 ton Goodman a few months ago with an 80 ft. line set & didn't add an ounce of gas but the charge was perfect. It should have needed about 2.5 lbs extra refrigerant to compensate for the line set so the unit was about 15% over charged from the factory. Also your indoor coil sounds like a match but if its too small that would also cause the problem you describe.

**crmont** · 01-27-2013, 01:16 AM

THPRE: are you in Oregon?

The last 4 ton goodman r410 system that installed called for a 7/8 suction line.

A partially restricted (kinked) suction line will cause high head pressures and fluctuations.

The static pressure tests is only effective if the blower is functioning correctly.

How and where are static readings taking place when there is likely no supply and return plenum?

The check me test is very tricky in a manufactured home unless a plenum was installed under the furnace and there is at least a 12" return air plenum.

I'd hazard a guess that the air handler has little or no supply plenum and it's installed to the rear of the mechanical closet. If so you'd hear a noisy cavitating sound. Likely the outlet of the air handler is pointed directly at the floor.

If your static pressure readings are taken beyond that point then they are not accurate.

The "check me" test is only relevant if the input numbers are accurate.

**THPRE** · 01-27-2013, 01:53 AM

Only phone conferences are available here. Very frustrating. We have sent pictures and now the static pressure reading to the consultant. I hope for some answers on monday.

**THPRE** · 01-27-2013, 02:06 AM

The suction line is 7/8 and the liquid line is 3/8. I was guessing before. We have a tight fitting cabinet that houses the airhandler with the filter opening on one side and the fresh air vent on top and yes the out let is pointed right at the floor and directly into the plenum which is judged by all the techs that have seen it as "adequate" -- not great . Never hear any cavitation type noises. The outlet plenum is at least 24in. deep but I don't know the other dimensions. The static air on the supply side was taken through a hole drilled in the airhandler cabinet just above the floor. So it is above the also above the plenum. Thanks,THPRE

**crmont** · 01-27-2013, 02:12 AM

Originally Posted by THPRE

The suction line is 7/8 and the liquid line is 3/8. I was guessing before. We have a tight fitting cabinet that houses the airhandler with the filter opening on one side and the fresh air vent on top and yes the out let is pointed right at the floor and directly into the plenum which is judged by all the techs that have seen it as "adequate" -- not great . Never hear any cavitation type noises. The outlet plenum is at least 24in. deep but I don't know the other dimensions. The static air on the supply side was taken through a hole drilled in the airhandler cabinet just above the floor. So it is above the also above the plenum. Thanks,THPRE

Well there you go. The discharge static pressure reading cannot be made through a hole in the air handler and it sounds as though the air handler is sitting right on the floor of the mechanical room. This is no good. Please post pics.

**crmont** · 01-27-2013, 02:16 AM

Also; this is why your return and supply static readings are the same.. Essentially you are reading the same negative pressure in two different locations. This is also why removing the supply duct from the plenum made no difference.

**THPRE** · 01-27-2013, 11:07 AM

The system has been evacuated and recharged numerous times while replacing the tx-valves and the drier. Also it passed the check me as to temp and pressures. I would think the charge would be correct by now. Yes the liquid line was considerably hotter than the suction line during our tests but I do not remember the actual temps. Could a restriction in a line [or a puddle,as Goodman sugested] cause problems in heat mode and not in cooling mode? And then if they adjust the charge for winter and it works,how would we explain the lack of cooling in the summer until more refergerant is added?

**beenthere** · 01-27-2013, 11:24 AM

Originally Posted by THPRE

Ok but if the system was wide open in the return and had a 16in. duct removed from the plenum and I was still watching 610psi to 400psi in under 1 minute cycles there must be a further prob;lem? I mean that with sstatic pressure minimal and cfm close to 2100 there should not be an air flow problem causing the 610 high side?

Might mean they had to over charge it in cooling mode to make it work with the low air flow.

**THPRE** · 01-27-2013, 11:29 AM

The return air pressure was taken at the air filter louvered opening with the filter removed and with the outside air vent open and closed. open was .04 and closed was .05. the other reading was right at floor level under the coil and blower. this was .25. These two readings gave the total of .30. The air handler sits in a very tight fitting closet,it is larger than the original electric heat unit. We had to remove the door and the door frame to get the unit in. The face is closed with a removable piece of sheet rock. This will be made permanent once the unit works. so above the air handler there is a space close to the same size as the air cabinet and approx. five feet tall above the air handler with the outside vent at the top and the filter opening on the front side. below the air handler there is a reasonable sized plenum with the original rectangular duct on one side and the new 16in. duct on another side. The 16in. was removed when we were on the phone with Goodman and there was no change in refergerant pressures. We were not reading static air pressures at this time .

**THPRE** · 01-27-2013, 11:50 AM

I must have misled you somehow. The two reading are different. Return is .05 and supply is .25 giving the total of .30. Yes I am in Oregon. 25miles up the Rogue River from Medford. The coil cabinet is on top with the blower underneath. Whole unit is about 6 inches off the floor on a sheet metal duct the same size as the air blower cabinet--this goes directly through the floor and becomes the under house plenum. This plenum is at least 24in. deep
under the house not including the part on top of the floor or the thickness of the floor. I will try to get pictures. Thanks THPRE

**beenthere** · 01-27-2013, 11:54 AM

So was the air filter removed, along with the outside air vent open, when it was charged in cooling mode.

Now, put the filter in, keep the louvered door closed, and then take the static pressure. Static pressure must be taken with the system operating in its normal set up to be accurate, or any indication of what is going on. The removal of the filter is not part of its normal operating conditions, so those static checks are meaningless.

**THPRE** · 01-27-2013, 12:30 PM

Ok but with filter out and duct off under house the air flow is optimal and the system was still not functioning. 610 to400 psi cycles in less than one minute. And yes everything was in place when the system was charged.

**beenthere** · 01-27-2013, 12:47 PM

Then the cause goes back to low air flow when it was first commissioned. And you haven't had a good tech out there yet. Seen what you describe more then once already.