Heat will not auto start


Old 01-06-16, 08:35 AM
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Heat will not auto start

-- Problem --

I am having this issue with the heating in my place. Basically the system does not auto starts when inside temperature goes down.

1- When it reaches the desired temperature the system stops but will not start again even when the inside temperature is well below the thermostat temp. I have to move the thermostat to OFF manually, wait a few seconds and move it to Heat for it to kick in after a few seconds.

2- I have also noticed when the heating finally is running (by manual trick) the burner takes many breaks.. so i sat down next to HVAC and noticed while its running, the burner will stop randomly and fan will continue to run and after 1 minute or so the burner will start again. and once inside temperature meets the thermostat the whole thing obviously stops. Is this normal behavior? or the system is under stress and something is wrong?

-- What I have tried so far --

It started 2 days back when it was actually the first cold day in VA with night temperature was 8F and when i woke up the house temperature was 63 with thermostat set at 73 and there was no activity on the HVAC.

I originally thought its a problem with thermostat. I had a Sensi (wifi) thermostat which i thought is doing something wrong and i changed it to the old style thermostat and nothing has pretty much changed.

The filter is pretty new (30 days i think) but i am willing to go out and buy a newer one.

-- Model of HVAC --

I am totally new to home ownership and i dont think i know all parts of HVAC. I have taken these pictures if they can explain what system I have. the brand is York.

The system is zero to five years old.

I also got the home insurance when i bought this place and that covers the HVAC but that thing has a $200 deductible for every call we make. so i want to ensure i have some knowledge of what is wrong so i don't end up making a call where nothing is wrong and or have to make multiple calls.

Any help is appreciated.

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Old 01-06-16, 10:25 AM
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You have a York Affinity 8.S furnace.

I can't read the model number off the tag in the picture.

There should be a diagnostic LED flashing somewhere on the unit. It sounds like the burner is shutting down due to high heat limit. That is a common problem caused by an airflow issue thru the furnace. The most common cause is a dirty air filter followed by too many closed registers, blocked return(s), dirty A/C coil or problem with the blower motor.
Old 01-06-16, 07:03 PM
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Thank you for replying. Appreciate your time.

That may not be the correct model number. I opened the cover of it and was able to look up the model number. The model number is PS8B16N100UH11b.

I was also able to peek through the system when it went into that "idle" mode and it had a red light blinking 4 times and will go off for 2 seconds and will also blink for 4 times.

I have looked up the pdf here


Are these error codes vendor specific or more general? i am trying to find more details of this error code but if you have any ideas please let me know.

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