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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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We have a York Affinity YZB which was installed in October

Customer Question

We have a York Affinity YZB which was installed in October 2009. Last February (2015) we started having problems. The outside unit would stop working in cold weather but the inside fan continued to run and the thermostat said heat on. The dealer came and rewired the controls (they did the wiring in the first place). They returned and changed a sensor in the outside unit. We continued to have problems. A new thermostat was installed and the fan motor in the outside unit was replaced. By that time it was spring and the outside temperature moderated, the unit worked properly all spring and summer including the air conditioning. When the temperature dropped late this fall the outside unit ran in the morning, along with the auxiliary heat and brought the temperature in the house up to the set temperature. Later in the morning the outside unit stopped working and the temperature in the house dropped from 72 to 67. The dealer came back and determined that the sensor was defective. A new one was installed. Between then and now we had mild weather and no problems. Yesterday it got colder. The house warmed up in the morning but by noon it was down to 69 and the outside unit was not working. It did not run all day yesterday and the auxiliary heat did not come on. The thermostat says "heat on" but there is no heat at all. It seems that the auxiliary heat only runs first thing in the morning. The repairman doesn't seem to be able to figure out what is wrong. Do you have any suggestions?
Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.


That is indeed a complex situation. We should check a few basics first. Is the air filter clean, and do you have furry pets in the house? A dirty heat pump coil that fits one either end of the furnace will block air flow and cause the heat pump to go off on its high pressure cut out switch.

It is also probable that after 5 years the radiator (outside unit coil) is clogged with dirt deep between the fins where it cannot be seen, after 5 years it will need cleaning if it has not been cleaned in the last 5 years.

None of these however address the back up heat not coming on, we can address that separately.

You can buy a condenser coil cleaning kit at most larger hardware stores or departments... be careful not to let the pets eat the resulting foaming cleaner.

Let me know about all that, we can go from there.


Customer: replied 1 year ago.
The filter is cleaned monthly and there are no pets in the house.
Expert:  Phil replied 1 year ago.

Thanks, ***** ***** when the finned coil on the outside was cleaned please. That will be a problem if not cleaned, it is probably not the entire problem, but could be a major part of it.


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