Buderus GC144 Issues

Matth10

Gooday, I'm having some issues with my 7 year old Buderus GC144 natural gas boiler/ Aquastat controller with radiant in-floor heat.

The pilot light starts fine but when it goes to the burn stage it kicks off and does this 7-8 times until it fully lights and it does this every single time. The igniter board blinks three times which indicates a recycle code.

Also once running, I can hear dripping on the burner every 10 seconds or so and there is charred bits and soot on the ground underneath the boiler. Would this 100% indicate a cracked heat exchanger as the boiler would still be under the 10 year warranty.

There is also a strong sulphur type smell coming from the boiler, I have the damper held open and confirmed it's exhausting fine out the chimney outside but can even smell the odour outside so it's definitely not burning clean. I ran it for an hour and eventually the CO alarms picked up about 40ppm.

Luckily it's been a mild winter so far and I recently had an air source heat pump system installed for air conditioning so I've been using that but once it gets below -20 I can't run it.

Big Ed_4

You have carbonized boiler , it needs to be pulled apart and cleaned out . Shut it Down !

Ironman

Very unlikely that a Buderus cast iron boiler under 10 years old would leak - but possible.

You obviously have combustion issues and a very dangerous situation.

You need to shut it off and have a competent pro look at it immediately.

The dripping water may be from the flue gases reaching dew point.
 

DON’T operate it! Shut it off!

Matth10

Update, had two different techs out and the one right away just said to replace the unit so got rid of him. The other one has been out twice, he gave it a good clean and adjusted the air/fuel twice. It works for about a day and then goes right back to the same issue of shutting off and throwing a recycle blink code. 

The weird thing is that as long as my front door is open which is about 5 feet from the boiler, the boiler will usually fire right up just fine and second I close the door it will shut down so obviously an air/fuel issue but has the tech stumped. Anyone ever seen anything like this, any other possible fixes?

Jamie Hall

Sounds to me like the poor thing is being starved for air. How tight is your building? Are there any exhaust fans which run? Where does the furnace get its combustion air when the front door is closed?

Matth10

The house is quite tight as built in 2003. I have an HRV unit but don’t typically use it besides exhausting moisture in bathrooms during showers. 

There is a fresh air intake a couple feet from the boiler, it used to have a filter type chamber on it but I have removed it and didn’t make a difference. Can definitely feel the cold air within the boiler closet. Now that I’m thinking about it, it seems to have all started after I had a greener homes evaluation done where they sealed the house and used a blower to determine any drafting in the house. Now every time I open my front door a large incoming air presence is noticeable which I think helps with the air/fuel starvation compared to the typical fresh air intake beside the boiler. Negative air pressure issues????

Big Ed_4

There you go , they sealed up the fresh air needed for combustion .

kcopp

IMO... if your home is that tight I would opt to do 1 of 2 things.
Install a "fan in a can" or replace w/ a unit that is a sealed combustion unit that draws it combustion air into the boiler directly.