Author Topic: york stellar heat pump desparately needs help  (Read 5910 times)

Offline gaston

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york stellar heat pump desparately needs help
« on: July 19, 2012, 05:11:19 PM »
I have a York 3 ton Heat pump currently operating in Cooling mode. The unit appears to be working well in that I am getting about 20 degrees of cooling in air crossing the evaporator coil. The unit seem to cool the house properly as long as it continues to operate.

However, the unit occasionally shuts itself down and the Red LED on the Thermostat displays a pattern of three rapid blinks repeated over and over.

If I power the unit off, the blink code clears and unit performs normally (possibly for a couple days) until the pattern repeats itself.

I have found that the blink code translates to the following:
"Discharge Temperature reaches approx 275 degrees F".

Can anyone advise exactly what this fault indicates and what type of repair is required? Is the system possibly either low or high in refrigerant charge?
 
I appreciate any and all information on this issue.

Thanks,

Gaston

Offline Admin

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Re: york stellar heat pump desparately needs help
« Reply #1 on: July 19, 2012, 06:15:55 PM »
My first thought is to clean the outdoor coil with a hose, but a plugged condenser coil would probably cause a 2 flash lockout. (Discharge pressure over 400psig)

I believe the reason the manufacturer has the discharge sensor is to avoid carbonization and oil breakdown, which could happen if the discharge temperature exceeds 225F.  It's protecting the compressor.

You have a tricky problem and there are many things that could be the cause.  I would try to monitor the discharge line temperature near the compressor, and see if the temp is actually near 225F when it trips.  It could be a faulty sensor causing the lockout otherwise there are 3 causes of high discharge temperature;

1. High condensing temperature
2. Low evaporator pressures and temperatures
3. High compression ratios.

To diagnose high condensing temperature I would check for the following,

Dirty condenser, high ambient temperature, noncondensable (air) in the system, condenser fan stopping intermittently, restricted airflow over condenser, refrigerant overcharge, wrong refrigerant, high heat load in evaporator.

To diagnose low evaporator pressure and temperature I would check for the following,

Dirty evaporator coil, iced up evaporator coil, evaporator fan stopping intermittently, shortage of airflow over the evaporator, frosted evaporator coil from high humidity, frosted evaporator coil from a bad defrost heater or other defrost component malfunction, low heat load on the evaporator coil, defrost intervals set too far apart on the time clock, undercharge of refrigerant, end of the running cycle, partially plugged filter-drier, compressor inlet screen partially plugged, restricted liquid line, wrong refrigerant, metering device starving.

High compression ratios are caused by high condensing pressures or low evaporator pressures, or both. If there are high condensing pressures or low evaporator pressures, or both, there will be high compression ratios.  This causes the heat of compression to increase and the compressor will have a higher discharge temperature.

There's a lot we can rule out as your problem exists in cooling, and it seems to be intermittent.  However you really need a set of gauges to verify the pressures, and a temperature probe to verify temperatures.  We need to see if the problem is coming from the evaporator or condenser.

Do you have an electric furnace as AUX heat?  Is it possible one of the elements is energizing during a call for cooling?  Use a clamp on meter and see if there are any amps going through the elements.

Is there not a 5 year warranty on your heat pump?  I would try to get a technician to come by, unless you have the diagnostic equipment.  I'm very curious to know what's causing your problem.  Let me know how things work out.

Offline gaston

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Re: york stellar heat pump desparately needs help
« Reply #2 on: July 19, 2012, 06:38:41 PM »
Yes I have electric auxliary and the tech is coming out again next week.

Just to add:  3 Years ago, I had to disconnect it and remove the outside unit away from the house for about 2 weeks for some concrete work.  It worked fine up to that point in time.  Ever since this problem has existed and the York tech man been to isolate it.

On his next trip, he's going to evacuate the system, check the amount of R22 in the system, change the filter dryer and re-charge the system.  I'm thinking that there may be some condensation in the lines from the time that it was disconnected.

thanks for your previous thoughts.

Does this change your way of thinking now?


"G"

Offline pas1216

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Re: york stellar heat pump desparately needs help
« Reply #3 on: July 19, 2012, 06:53:27 PM »
has the tech tested the discharge temp sensor? I would get him to do that BEFORE doing anything else.

Offline gaston

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Re: york stellar heat pump desparately needs help
« Reply #4 on: July 19, 2012, 07:33:57 PM »
Yes the discharge sensor has been changed.  Problem still exists.

Any further thoughts.

Thanks for all the info guys, keep it coming.

"G"

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Re: york stellar heat pump desparately needs help
« Reply #5 on: July 19, 2012, 09:05:21 PM »
The relocate could have caused a contamination or allowed a non condensible to enter the system.  The next step in your plan will certainly rule out alot of possible causes. 

Have him evacuate the system, replace the filter drier, purge, vacuum and recharge.

How old is this unit?  Since it was relocated have you had problems with the heating mode?

Offline gaston

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Re: york stellar heat pump desparately needs help
« Reply #6 on: July 20, 2012, 06:17:41 AM »
The unit is about 6 years old.  When the system is in heat mode, it also has the same problems.  Both cooling and heating mode, the same symtons appear.

thanks

"G"