York Heatpump AUX heating problem

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Old 11-08-14, 03:13 PM
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York Heatpump AUX heating problem

Here's the unit information: York 2.5 ton 13 SEER
Model of condenser coil unit is: G2FD036S17A
Model of air handler is: N1AHB1206A-Down draft
Here is my problem. This started last winter. When the temps outside drop below 30 degrees, the aux heat strips will activate to augment the heating process. This acts, as it should. During an exceptionally cold snap, I found that the blower would be running, with heat coming out of the registers, and then the blower would shut off, and before it finished spooling down, it would come back on again. Only, the heat would be gone. The blower would simply be blowing the existing air around. Woke up one morning to it being 58 degrees in the home. The aux heat was gone, and it would be too cold outside of the heatpump to extract any heat. Turning off power to entire system, was the only way to reset the system into using the aux heat, again. I found there is a limit switch installed just under the heating elements. So, thinking that the filter I had installed in the fall was too restrictive (therefore, kicking off the limit switch), I removed the filter, and reset the system. With the filter removed, the heat elements would come on, stay on when needed, and the entire system operated properly......minus the filter. On the off chance that the problem was a bad limit switch, I replaced it (Open 210, Close 180). Problem still continued.
Over the summer, the winding went bad in the blower motor. So, replaced the blower motor. When I wired up the new motor, I wired it to run at the highest speed (thinking I needed to push as much air as possible to keep the limit switch from kicking the heat elements off, during the winter).
This fall, I had a technician out for a fall tune up. Explained my problems from last winter. He ran a cfm reading and said the air handler was pushing almost 2400 cfm(right below the air handler), which was about 1000cfm more than it should (especially during heating months). And, he said that it was pushing so much air, that when the heating elements were on, they wouldn't even "glow". He deduced, that he didn't think the limit switch would ever get hot enough to kick off the system. He recommended that the fan speed be reduced to medium. That was done. The other night it got down to 25 degrees outside, and I knew the aux heat was going to come on. So, I waited to see if the same problem would occur. And, it did. Once again, I removed the (very basic) filter. Reset the system by turning it off at the breaker. And, it was fine afterward (without the filter). System is about 10 years old, and up to last winter, has worked fine. This summer, I cleaned the condenser coils in the air handler, and the coils in the outside unit. All registers are kept at wide open, so as to not restrict any air flow. And, all register have very good air flow (doesn't seem to be any blockages or restrictions). Spent hours looking through forums and talking to techs in the business. This problem continues to leave me scratching my head. Hope someone has some ideas.
 
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Old 11-08-14, 03:18 PM
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That's a lot to take in. Can you simplify the question?
 
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Old 11-08-14, 03:31 PM
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I know, sorry. Wanted to make sure I gave as much info as possible.
When aux heat is in use, it will activate some type of safety switch (killing the heat) which requires a power cycle to reset. When filter is removed, it doesn't happen. Limit switch replaced and cfm's are well above what is needed. What else could be causing this problem?
 
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Old 11-09-14, 08:26 AM
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1) here's a section from my York air handler manual which may offer a clue:
....
Limit Switch and Lockout Operation

Limit Switch Operation
If the HEAT ENABLE jumper is in the HEAT position and the limit switch
opens (fault code 1), the control will immediately de-energize all electric
heat relay outputs and energize the blower (if it wasnít already energized).
When the limit switch closes, the control will re-energize electric
heat according to the thermostat inputs using normal timings.

Fan On Lock Condition
If the limit switch opens multiple times during a single call for electric
heat (fault code 3) or if the limit switch opens for a long duration (fault
code 4), the control will energize the blower until power is removed from
the control. The control will cycle the heat outputs on and off as the limit
re-closes and opens. The constant fan operation will signal the homeowner
that a problem has occurred and a service call is required.

Soft Lockout
If the limit switch opens for a second long duration period during a single
call for heat (fault code 5), the control will keep the blower locked on
and lock out the heat outputs for one hour. The control will only reset
this one hour lockout when the power is removed from the control. After
the one hour period has passed, the control will re-energize electric
heat according to the thermostat inputs using normal timings. The
blower will remain locked on from the first long duration limit opening.

Hard Lockout
The control has a hard lockout condition during which the control will
keep all heat outputs de-energized until power is removed from the control.
The control de-energizes the blower five minutes after entering the
hard lockout condition.
If the limit switch closes and re-opens during the one hour soft lockout
period, the control will enter a hard lockout condition and continue to
indicate a fault code 5.
If the limit switch opens twice when no call for electric heat is present
(fault code 2), the control will enter a hard lockout condition.
If the limit switch opens multiple times soon after a soft lockout reset
(fault code 6), the control will enter a hard lockout condition.
Wiring Related Faults
If the control receives a simultaneous call for heating and cooling (fault
code 7), the control will perform both heating and cooling operations.

.....

2)read this post for possible help - item 10, probably applies to your system ...
http://www.doityourself.com/forum/he...ring-help.html

I'd check :
-for fault codes on both the inside and outside units
-when the condition occurs, check the control wiring for W1,W2 signals in the air handler , probably not present but if they are then blame controls in air handler.
-also check W, if it's on and W1,W2 aren't then suspect outdoor unit control board
- is G , 24V from thermostat, on ?
- temporarily jumper W1 to a source of 24V, e.g. G, or R and see if a heater comes on.

If it's the outdoor unit controls you can restore emergency heat by directly connecting the W wire to W1 and W2 at the air handler
then the heaters are directly controlled by the thermostat.
Note the wiring diagram , item 6 in the post, see that W goes directly from the thermostat to the outdoor unit; chances are, the wire passes through the air handler, probably a wire nut to connect the wire from the thermostat to the wire to the outdoor unit
... but in any case if you do wire W1,W2 diectly to the thermostat W, make sure you disconnect the W to outdoor connection, otherwise you can end up with the heaters permanently on.

Sorry this is so long :-)
 
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Old 11-09-14, 12:00 PM
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It's got to be a air flow problem. Dirty coil, dirty blower or dirty filter.
 
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Old 11-10-14, 04:49 PM
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Sorry it's taken me some time to get back to this. Have a demanding day job.
I can say that the filter, coil, squirrel cage and plenum are not dirty and therefore, not the culprit.
To "dsomerv" information, I will say that the system is most likely acting like the "Fan on Lock condition". The unfortunate part is, I think this system is too old, or simple, to have any way of "reading" codes. Or, I don't know where to get the codes from. But, the symptoms described, is what is happening. It will lock the fan on, and lock the heat strips off (until I kill the power).
I plan to re-check the wiring, on my next day off. The link you had sent regarding this, will be very helpful. And, I learned today, that the motor a tech installed this past summer, isn't correct. It's a Its an AO Smith 3/4hp, 1075RPM 115V 3SPD DD 6P Motor. Problem is the air handler is 208/230 volt and specifies a Motor 2.9 FLA, 1/2 HP 3 PH, 60HZ. So, the motor isn't likely to last long.
 
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Old 11-10-14, 05:29 PM
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Here is link to a parts manual for your air handler:

http://www.master.ca/documents/0NAHRepairParts-0303.pdf

The second column of model numbers at the top of page 2 lists the parts for your air handler. From the symptoms you are describing it sounds like your fan electric heat control is bad. It is part number 031-01264-002.

It shows the correct part number for your blower is 024-26087-000.
 
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Old 11-10-14, 07:32 PM
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Thank you firedawgsatx. This will be very helpful.
I have a new theory, that might explain my problem. But, I'm looking for feedback. And, this might be what you were referring to.
If, there was a problem with the heat relay or sequencer (ie, the relay or sequencer closes the circuit to the heat coils and doesn't cycle them on and off), could this be causing the heat coils to produce enough heat that the limit switch opens at 210 degrees? Thus causing the "Fan on, Heat lockout" condition. Therefore, by removing the filter, this allows just enough more air to pass over the heat coils to never let them reach the limit switch, top threshold.
 
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Old 11-10-14, 07:41 PM
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Here is some additional information that may be useful to you:

http://www.upgnet.com/PdfFileRedirec...002-B-0704.pdf

Page 5 provides some info about the heating controls. You would have to test the control board to see if voltage is present at the heating coil(s) when it shouldn't be.
 
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Old 11-14-14, 04:34 AM
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Spent several hours yesterday, trying to troubleshoot this problem. I learned that the temp coming out of the nearest register (with Aux heat on) is about 110 degrees. The temp inside the heat kit (right at the heating elements) max's out at 128-130 degrees. At that time, all three stages of heat were active for approximately 10 minutes. Based on this, there is no way, the heat limit switch (rated 180-210) can be sending this unit into fan lockout. Through process of elimination, I'm going with there being a problem with the control board, or the 1st stage heat relay, on the board. So I've ordered a new board. Will try to give an update, once that replacement arrives and is installed.
 
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Old 02-14-15, 10:17 AM
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I'm very interested on how the control card replacement worked out for you. I have the same equipment and the same problem. Everything worked fine for the fist ten years. When the temperature is above -12degC the heat pump kicks in and heats the house. Below that temp. the electric furnace will heat the house for a few hours, and at some point after a few heating cycles when thermostat calls for heat, fan comes ON but no heat. I have tried replacing the first the thermostat, then the control card, then the high limit switch and no change.
 
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