[mikehorrocks]

A couple of questions about my 7 month old York YZB02411 with the MV12BN21 air handler, MC30B3XH1 coil and Braeburn 5200 thermostat. First, for this configuration, would you please indicate all of the correct low voltage wiring connections between all units. Secondly, what does it mean when the large pipe from condenser entering the air handler is too hot to touch but the air flowing from the registers is not that warm. Next, I am not sure my electric heat is coming on during the defrost cycle, i.e. high fan, compressor running (cool?) large pipe is cold, condenser fan off, cold air from register. And finally, at 10 degrees F outside temperature, is it normal for the room temperature to be 2 degrees below tstat setting? Thanks, Mike

[hvac1000]

A couple of questions about my 7 month old York YZB02411 with the MV12BN21 air handler

Mike your questions will be much better answered by the professional installer that did your install. Call the company you bought the equipment from since your equipment is still under warranty.

The low voltage wiring connections are in your manuals that came with the equipment. The rest of the questions you are asking can have many variable answers so it would not be of benefit to you if I just took a guess. If you are having problems with your unit or you believe your unit is not operating properly arrange for a ON Site Inspection by the professionals that installed your system. The worst part of all this is if you decide to work on your equiptment it will possibly violate the warranty so you do not want to mess with it. You paid to have the work done correctly so if you are not happy or have questions call back the company that did the work for you. This is the best and most solid advice I can give you.



A couple of questions about my 7 month old York YZB02411 with the MV12BN21 air handler, MC30B3XH1 coil and Braeburn 5200 thermostat. First, for this configuration, would you please indicate all of the correct low voltage wiring connections between all units. Secondly, what does it mean when the large pipe from condenser entering the air handler is too hot to touch but the air flowing from the registers is not that warm. Next, I am not sure my electric heat is coming on during the defrost cycle, ie, high fan, compressor running (cool?) large pipe is cold, condenser fan off, cold air from register. And finally, at 10 degrees F outside temperature, is it normal for the room temperature to be 2 degrees below tstat setting? Thanks, Mike

[mikehorrocks]

I was looking for a second opinion. Heat pump wiring information when you use a different thermostat than what is indicated can be confusing. I was looking for basic operating principles at low temperatures. For example, if the heat pump can not keep up with the low outside temperature, the electric back up I believe will kick in when there is a 2 degree differential in the room. This back up heat will stay engaged until the thermostat is satisfied. Next heat cycle only the heat pump will run until it is determined that it can not keep up with the low outside temp and the cycle is repeated. I interpret this behavior as your room temperature will cycle from set point down to set point minus 2 degrees and back up to set point and then be repeated. This operation seems crazy as the unit can not maintain a steady temperature when cold outside. Is this the way they all work? Also, I was concerned that the coil in my air unit was not always transferring the heat out properly. I did not know if there could be a intermittent blockage. Regarding the defrost cycle, I am going to have to monitor it more closely to determine if it is working correctly.

A couple of questions about my 7 month old York YZB02411 with the MV12BN21 air handler

Mike your questions will be much better answered by the professional installer that did your install. Call the company you bought the equipment from since your equipment is still under warrenty.

The low voltage wiring connections are in your manuals that came with the equipment. The rest of the questions you are asking can have many variable answers so it would not be of benefit to you if I just took a guess. If you are having problems with your unit or you believe your unit is not operating properly arrange for a ON Site Inspection by the professionals that installed your system. The worst part of all this is if you decide to work on your equiptment it will possibly violate the warrenty so you do not want to mess with it. You paid to have the work done correctly so if you are not happy or have questions call back the company that did the work for you. This is the best and most solid advice I can give you.


A couple of questions about my 7 month old York YZB02411 with the MV12BN21 air handler, MC30B3XH1 coil and Braeburn 5200 thermostat. First, for this configuration, would you please indicate all of the correct low voltage wiring connections between all units. Secondly, what does it mean when the large pipe from condenser entering the air handler is too hot to touch but the air flowing from the registers is not that warm. Next, I am not sure my electric heat is coming on during the defrost cycle, ie, high fan, compressor running (cool?) large pipe is cold, condenser fan off, cold air from register. And finally, at 10 degrees F outside temperature, is it normal for the room temperature to be 2 degrees below tstat setting? Thanks, Mike

[hvac1000]

Heat pump wiring information when you use a different thermostat than what is indicated can be confusing

I have no idea why it would be confusing. It either works or it does not work. The wiring was done for you by the contractor so why are you looking at it to start with? You might be confused because you are looking at something you know nothing about? I suggest a course in HVAC at a local trade school if you want to learn the trade. I do not and will not teach class here. This board is simply here to help people who have a broken unit and are looking for simple ideas that they can do to affect a repair.


For example, if the heat pump can not keep up with the low outside temperature, the electric back up I believe will kick in when there is a 2 degree differential in the room.

Basically that is the proper operation except the 2 degrees can vary at times. The electric back up also kicks in every time the heat pump goes into defrost to clear the frost off the outside coils.

Next heat cycle only the heat pump will run until it is determined that it can not keep up with the low outside temp and the cycle is repeated.

The next heat cycle will be just about the same as the first heat cycle and this is normal.

Is this the way they all work

Yes this is a normal heat pump cycle. The heat pump always comes on first the when it can no longer keep up the electric back up heat will come on. If it did not work that way the system would never be able to actually heat the home. If the thermostat controls were set any tighter than 2 degrees swing it could cause problems with over ride and cause further problems and waste more energy.

Also, I was concerned that the coil in my air unit was not always transferring the heat out properly. I did not know if there could be a intermittent blockage.

The indoor coil will transfer the heat from the outside unit unless it goes into defrost then the indoor coil will actually become the air conditioning coil and you will have the system in reverse for a short time. Anything is possible but you could be confusing the defrost reversal and the temperature of the lines being different as an intermittent blockage. Anything is possible but you would have to have refrigerant gauges hooked up to the system and watch the pressures to see if any true blockage exists. I do not believe you have any blockages.

NOTE: you can stand by your window and watch the defrost cycle all day long if you wish. It is automatically controlled by a circuit within the outside unit. Heat pumps are not perfect but they do save energy in milder temperatures. Once the temp outside goes down past 35 or so the heat pump looses most of it efficiency. Usually there is a control installed to prevent the heat pump from spinning its wheels and just pumping away without producing any heating advantage. This control is sometimes not installed so different systems will act differently.