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Phil, I have this exact problem error code 643 with my

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Hi Phil, I have this...
Hi Phil, I have this exact problem error code 643 with my Noritz boiler. My original problem was no error code but the boiler would not heat up. I suspected it need to be flushed due sediment buildup. Turned back on unit and we got 643 error code. It was 5:00 and said he didn’t know what that code is. That was a week and a half ago. No word from them. Anyway my suspect is it needs to be bled. Can I do that my self. Thank you
Submitted: 3 months ago.Category: HVAC
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Answered in 15 minutes by:
12/26/2017
HVAC Technician: Phil, Mechanical Engineer replied 3 months ago
Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 9,312
Experience: Retired HVAC/ Electrical & Boiler contractor. Industrial
Verified

Hello, do you have a Noritz hot water heater? Is it used to heat the house, or just for domestic hot water. I need the model number of the Noritz heater in order to pull the manual on it.

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We can go from there.

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My goal is to give you the best experience possible! I hope I have earned a 5 star rating! Please remember to rate my service by selecting the 5 stars at the top of the screen before you leave today. If you need more assistance, please use the reply box and let me know.

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Customer reply replied 3 months ago
NH - 1501 -dv -Ng Yes its a boiler to my hvac system
HVAC Technician: Phil, Mechanical Engineer replied 3 months ago

Thanks'

Click here for photo's of air vents.... however if you have under floor heating then the air is removed by flushing each loop, its a different tactic... tell me what type of floor loop controller you have or what type of radiators. We can go from there.

Code 643 is a water flow switch failure and indeed most likely is air trapped in the system

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HVAC Technician: Phil, Mechanical Engineer replied 3 months ago

Hello, that looks like one of the air vents, operate the little knob on top until a tiny squirt of water come out.... but do look for several other air vents in the system, some look like a slotted screw fit into a small brass piece... the give away is that all air vents are located at a high point in that section of the system.

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Customer reply replied 3 months ago
I found the safety release Valve lifted that was able to get burner to come on for 3 min. How long is typical to bleed system
Customer reply replied 3 months ago
It gets better the longer I run
HVAC Technician: Phil, Mechanical Engineer replied 3 months ago

Bleeding takes less than one second as a rule, you bleed until just a tiny squirt of water comes out... the system must be under 15 to 20 psi pressure when you bleed... repeat bleeding of all the air vents is often necessary, as the air bubble tends to travel around the system

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HVAC Technician: Phil, Mechanical Engineer replied 3 months ago

My goal is to give you the best experience possible! I hope I have earned a 5 star rating! Please remember to rate my service by selecting the 5 stars at the top of the screen before you leave today. If you need more assistance, please use the reply box and let me know.

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Phil
Phil, Mechanical Engineer
Category: HVAC
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Experience: Retired HVAC/ Electrical & Boiler contractor. Industrial

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