AC Went out.

Discussion in 'HVAC Heating & Cooling' started by Auger1981, Jul 13, 2013.

  1. Auger1981

    Auger1981 New Member

    Messages:
    19
    Location:
    SC
    I have a manufactured home with a E2EB-017 HB Furnace.

    This unit has been a nighmare since I moved in here. The latest headache was the drain hose became dislodged from the drip pan. The condensation ran all over the circuits.

    Currently the unit will not start up at all. I have checked all the breakers (main panel & inside). I have tried to run just the fan, by switching it to FAN-ON and nothing happenes. I removed the blower fan / capacitor. There are no reset buttons on the motor. The capacitor appears to be fine both in apperance and by using a multimeter (appears to charge & discharge when reading it in ohms).

    The main relays were soaked as well, but they have been dried out. Readings on them appear to be fine. Although the main contactors appear a little charred, nothing looks out of the normal. Besides, if I am correct, the main contactors are mainly used for supplying power to the heating elements, and therefore would not be used when using AC. If I am wrong, please correct me.

    This leaves me with basically 3 items left. The transformer, the sequencer, & the thermostat. The transformer appears clean, and I dont think it got much water on it. The sequencer was soaked. Using a meter I can read the relays and nothing appears to be stuck (ie NC is closed, and NO is open).

    So this leaves me where I am at the moment. My question is this:

    If I turn on JUST the fan from the thermostat, does it bypass the sequencer ? I have an electronic thermostat, and can not remove the cover to check voltages without basically unplugging it. The controls sandwitch to the junction box with male prongs.

    I'm still leaning that the sequencer may be bad, but am totally lost at this point. ANY input would be greatly appreciated.

    Thank you in advance !!
  2. DonL

    DonL Out of the Trades

    Messages:
    3,909
    Location:
    Houston, TX
    For just the indoor fan, then the sequencing should Not be a factor.

    You need to check to make sure your 24 VAC. or whatever Low Voltage that it uses is working. Then go from there.


    Good Luck.
  3. Auger1981

    Auger1981 New Member

    Messages:
    19
    Location:
    SC
    X-frmr.jpg

    How would I properly measure the voltages on this please ?

    Black to Ground, and Red to each post ? (Adjusting the meter properly of course).

    The post at the top, both have a triangle symbol under them, and it says 24vac in the middle between them. On the picture it is above the upper bar code, obstructed by the grey wire.
    Last edited: Jul 13, 2013
  4. Auger1981

    Auger1981 New Member

    Messages:
    19
    Location:
    SC
    Xfrmr2.jpg

    Different view.
    Last edited: Jul 13, 2013
  5. DonL

    DonL Out of the Trades

    Messages:
    3,909
    Location:
    Houston, TX
    Being very careful not to touch the bottom two terminals, Just measure the top 24 Volt output with your Voltmeter set on AC voltage, and proper voltage scale to read 24VAC.

    Their may be a safety shutoff close to where that transformer is located, the power will need to be On.

    Be Careful.


    Good Luck.
  6. Auger1981

    Auger1981 New Member

    Messages:
    19
    Location:
    SC
    OK, update time...

    Read voltages results as follows:

    COM - 115 VAC - Good
    240V - 118 VAC - Not Good
    24V - Upper left (Purple lead) - 24 VAC - Good
    24V - Upper right (Grey Lead) - 0 VAC - Not Good

    Will be replacing the transformer tomorrow when a parts store opens.
    I will update this post one way or another.
  7. DonL

    DonL Out of the Trades

    Messages:
    3,909
    Location:
    Houston, TX
    I think You are measuring Wrong.

    You should be measuring the voltage Across the 24 VAC output and not to ground.

    The Transformer is isolated from Ground.

    The transformer sounds like it is good, But you may be measuring wrong.

    Were you measuring from the terminals to ground ? Or across the transformer windings ?

    If you were measuring to ground, then your transformer is most likely Good.

    You are working on AC and not DC, So the Ground is neutral, or should be.

    You may need to "Call The Man", as Andy G. would say.


    Good Luck
    Last edited: Jul 14, 2013
  8. Auger1981

    Auger1981 New Member

    Messages:
    19
    Location:
    SC
    If your talking reading the posts across the top, (grey to purple lead), the the voltage is 25vac +/-.
  9. DonL

    DonL Out of the Trades

    Messages:
    3,909
    Location:
    Houston, TX

    Then I would say your transformer is working.

    You have another problem.

    Have you tried to cycle the breakers that feed the unit ?

    Is the 24 VAC making it to your thermostat ?

    This may be past a DIY fix, without being there, it is all a best guess.
  10. Auger1981

    Auger1981 New Member

    Messages:
    19
    Location:
    SC
    OK, heres the final update... I hope.

    Rechecked the power at the breakers in the furnace. Found one lead that had no power. Turned off the power & ohm checked it. One side was open. Took out the breaker, cycled it a number of times & rechecked. Now it worked. But still no AC. Chased the 24v line and rechecked the inline fuse, this time it read OPEN. Replaced it and "ta da" we have AC again !!

    Can see the condensation draining from the pan. When the bottom cover is put back into place, the water shifts its flow, and appears to be sucked under the cooling coils causing water to drip on the blower, and run down towards the wiring/circuitry. Other then cleaning the coils more or replacing them, not sure what I can do. The coils were extrememly dirty when i bought this place, & no filters had ever been used I don't think.

    I know the coil replacement requires a certified person (at least in this state it does), so I'm afraid my work here is done. I want to thank you for all your assistance & for putting up with a slow old man. Been a while since I played with electricity / electronics & it sure felt good.
  11. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,892
    Location:
    New England
    The drain line should be installed per the instructions, which means it should have a trap on it. This may or may not help with it sucking from the drain line - it should.
  12. Auger1981

    Auger1981 New Member

    Messages:
    19
    Location:
    SC
    I think you misunderstood, or I need to explain better.

    It's not sucking water up from the drain line. Because the coils are partilally obstructed, air can not get thru them as it should. Some is but not enough.

    Here is an example of what I did:

    If I leave the bottom cover of the furnace off: Air flow is higher at the vents. Condensation drains as it should. Air is not as cool as it should be. After a period of time, coils frost over. Reason - Air bypassing the coils thru the bottom where the fan is located.

    Placing the bottom cover on the furnace forces all the air to be drawn thru the coils, rather then bypassing them. The warmer air from the house is drawn thru the coils to cool & also prevents frosting. Condensation should roll down into the pan, and drain. But because the air flow thru the coils are restricted, air is sucked in under the pan between the coils & the pan and then run down on top of the blower, and all the circuitry.

    As i said, this furnace was totally abuse before I got here. Wiring was messed up all over. The fan was wired backwards so that in the On position, it worked as it should, but in the Auto position it ran constantly. Wiring used was too short in length from the thermo & heat pump to the point they are wire capped and strung like a banjo.

    I can correct the wiring & plan on doing so this week. But coil replacement or removal/cleaning requires a license in this state, so it's time to call a pro either way.
  13. DonL

    DonL Out of the Trades

    Messages:
    3,909
    Location:
    Houston, TX
    Nice that you have it going. Good work.

    You should not operate it with the covers removed, for safety reasons.

    It sounds like your system may not be leveled properly.

    You should be able to clean the coil yourself without removing it. Spray cleaner and a water hose / air hose.

    If you do not open the refrigerant line then you should not need a license.


    Good Luck.
  14. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,892
    Location:
    New England
    It sounds like your air return ducts are not sized properly or are obstructed in some manner. There's a number in the installation manual (most likely) that indicates the acceptable pressure drop/air flow across the coil...sounds like your system does not meet the minimum requirements. It could be that the fan speed is set too high and exceeds your duct capability.
  15. Auger1981

    Auger1981 New Member

    Messages:
    19
    Location:
    SC
    OK, first to DonL - Thanks, like I said I love electrical/electronics. It is possible that it may be a little off level. I will look further into that. I have been trying to use cleaner on it, but as I mentioned, it was so dirty when I moved here, I pealed off the dust & dirt like a sheet of paper. In the mean time I've been trying to figure out what the tonnage of my heat pump is. I have a link to the specs - http://www.docs.hvacpartners.com/idc/groups/public/documents/techlit/ss-ph12-05.pdf - Its a model PH12NA048-B. If you or anyone is good with the calculations, or see it somewhere in there, please let me know. I need that info to order a new cooling unit, if I so decide.

    To Jadn - You may have missed that this is in a manufactured home. There are no return vents. The air is drawn in from above the unit thru a standard vented cover. This cover comes with the furnace from the manufacture. The cooling unit is an "A-framed" top down unit. The filters for this unit are "On-Coil" filters (I really hate them). The initial issue was the water drain hose falling off, soaking all the components below. We found and corrected 2 problems that were caused from the water, and the furnace is running again. Nothing was done to rewire or change anything.

    Again thank you for both of your responses.
  16. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,892
    Location:
    New England
    That vent may not be big enough for the a/c unit...there shouldn't be much pressure drop across the coil. That could be because it cannot pull the air in properly through the vent/duct, or whatever, or the fins of the coil are bent, or they're full of dirt or other deposits, OR, the fan speed is setup wrong. There's a certain amount of CFM that should be going over the coils based on the unit you have and the tonnage and the area of the outlet duct/vent or whatever. If the fan is set for higher CFM or the airway is restricted more than it should be, the pressure will move the water rather than letting it just flow down by gravity to the drain pan. There should be minimal pressure drop across the coil...when it is excessive, it can suck/blow water places you don't want it to go.
  17. Auger1981

    Auger1981 New Member

    Messages:
    19
    Location:
    SC
    One more question.

    I've checked the pan, and all seems to be leveled properly. Water flows to the drain on the side, ONLY if the air is off. The pan is rather dirty as you can imagine, and I plan on trying to clean it out the best I can. It is a very sung fit to the coils.

    What I'd like to try is to do a serious cleaning of the coils, just short of hosing them down. I'm looking to pull the fan and try to blow out the coils in the opposite direction of normal air flow. I know all the electrical components below, and am rather confident I can take the necessary precations to protect them from any water. Here is the question.

    What would you recommend to use to try & clean the coils. I need something that will really really cut thru grease & dirt. (Also hair as I think the previous owner had dogs). I'm quite temped to use draino, but I know better... haha. What is the strongest thing any of you can think of that will cut the jumk, and not eat the coils ???

    Thanks
    Last edited: Jul 15, 2013
  18. Auger1981

    Auger1981 New Member

    Messages:
    19
    Location:
    SC
    Forget the cleaning, just isn't going to happen. I have used cans of coiler cleaner, and a few other things, but air just isn't getting thru properly. Either way at this point, the cooling coils will have to be removed. After all this, I can take a NEW can of compressed air w/ straw, point it at any section of the coild from inside, and barely feel any air coming out the other side.

    So, again I ask.... can anyone tell what the rating is (IE 2 ton, 3 ton, etc), from the data sheet I linked ? Here it is again-

    http://www.docs.hvacpartners.com/idc/groups/public/documents/techlit/ss-ph12-05.pdf

    The unit is a Payne Model PH12NA048-B ...

    Thanks again in advance !!
  19. Auger1981

    Auger1981 New Member

    Messages:
    19
    Location:
    SC
    4 ton maybe ???
  20. DonL

    DonL Out of the Trades

    Messages:
    3,909
    Location:
    Houston, TX

    It looks like that PDF has 4 different sizes.

    Take the TC (Total Capacity) from the spec sheet and divide it by 12,000 to get the equivalent in tons.


    Good Luck.

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