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Was there a part where the coil was looked at for being clean? Use a strong flashlight and see if you can see through it? I may have missed parts of the conversations here. The metal door stamped face types are tightly done- I use the needle nose and bend them open some.
Originally Posted by qwerty hvac I didn't read the the whole thread. Doh Sent from my iPad using Tapatalk HD LOL, yeah I sometimes skip too many post and don't realize I missed the important parts.
Originally Posted by beenthere You can do that, when you have good air flow. I didn't read the the whole thread. Doh Sent from my iPad using Tapatalk HD
Originally Posted by qwerty hvac I run mine at 68 with no issues. Sent from my iPad using Tapatalk HD You can do that, when you have good air flow.
Originally Posted by Tommyz23 A unit will not ice up when it's over charged. You just made me remember something from my childhood! Westhinghouse had a package unit that used a txv valve, that used SC to work with a big accumulater, the bulb on the LL,many a guy kept adding gas only to freeze more!
Originally Posted by techbill11 It is not a good idea to put the system to go below 70-72. I have seen this cause systems to freeze. I run mine at 68 with no issues. Sent from my iPad using Tapatalk HD
It is not a good idea to put the system to go below 70-72. I have seen this cause systems to freeze.
2-16X16 filter grilles are a bit small for 3 tons.
I had the customer remove the blower door and it never froze up for a week. I modified the blower door with two 16" square filter grilles and installed pleated filters. The next morning it froze up. House was 70 and they had stat set at 68. I told customer to repair the gaping holes in the flex duct in the crawl. (He doesn't want to pay me to do it) I also advised a new blower motor with three speeds so it can be set to move more cfm's. I am wondering if the furnace and duct system is too small for the new 3 ton system. The model numbers to all equipment are as follows: furnace: Coleman 7956856; coil: Mortex 96R36YOP, ser M0130130146 ; Condenser: Rheem RANLO37JAZ. I also find it strange that it usually freezes when they try to draw the temp down below 70. I'm not sure why that's necessary anyway. Frosting starts right at the outlet of the txv.
It used to have a 3 ton rheem r-22 system but compressor burnt out maybe for the same reasons that are causing these problems
Coleman mod 7956856 Ser 048880382
When you get the model numbers we will know the a/c system size. Some of these furnaces are rated for 2 ton's and some for 3. If your installing a 3.5 or 4 ton a blower kit will need to be installed to replace the existing blower. Here is some info on this. Manufacturer documents attached.
It seemed to me that the openings in the blower compartment door for return air were way to small and few . Like I said too when the door was off my subcool was right on target at 9. With door on it shot up to 11.9
So maybe 103PSIG which is 33°F for R410A. Just barely above freezing. Good chance its a low air flow issue.
Originally Posted by bjonesplumb To get back to the beginning, are we all in agreement that this ice up issue could be caused by the txv bulb being mounted upside down? Over the years, I have seen and have installed TEV bulbs in some difficult locations without regard for location of the capillary tubing. I can't say that I have ever been able to track a problem, icing or otherwise down to simply bulb positioning or orientation. Ehh. Maybe floodback to a few broken bulb straps, but that's understandable and logical.
I don't remember my pressures but I'm thinking 243 high side and over 100 on low side but I'm not exactly sure it was last Friday that I did it.
I agree i would check your airflow, also inspect the blower wheel, ive seen it where the blower wheel is caked up with junk that it doesn't move enough air across the coil. Inspect the coil too there is a chance its covered in junk too. Are we overlooking the possibility of low airflow and low charge possible? What are the pressures when the system is "working fine"?
Down flow. I only have temp and pressure readings from when the system was functioning properly. I will get the equipment info and post tomorrow.
Need to check furnace to see if blower is rated for a/c tonage? Sometimes the furnace blower has to be changed out to a larger assembly for proper air flow. Jumper duct under coach needs to be installed and connected. Check air flow from all s/a registers. Post size of system, model numbers of equipment both indoor and out. Model number of indoor coil. And as asked is this a downflow system or upflow? John
We still don't know what the pressure readings were at any point. Everything points to low airflow so that's why pressure & temp readings would help. A faulty TXV is always suspect nowadays since they're so common too. If the airflow is O.K. & pressures & temps are O.K. then two other possible things could be the blower motor cutting out(circuit board , relay, motor, even loose wire) or the outside contactor is sticking intermittently.
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