Rainwater Entered Oil Boiler from Flue Pipe

Ahomeowner

Rainwater hit the ground and seeped below grade and then migrated into the chimney where it entered the flue pipe and then went into the boiler.  We have a flue liner which is in good condition but it is not watertight.  The boiler was off when this happened and it is still off. Unfortunately this happened twice because I thought the first time was a fluke. There was water sitting in the firebox (visible though a viewing port) and I believe there was also water in the burner because when I removed the cover on the burner, there was water inside the cover.  All of the cast iron is now very rusty.  I’m thinking that after I fix the chimney, I will need to get a professional to come evaluate it and fire it up for the season. Any ideas on what kind of damage I might be facing?  The plan was to use this until we convert to heat pumps so I’m hoping for the best. It’s a Burnham combi-boiler.

HVACNUT

Show where it's coming from the chimney. What's the chimney look like above grade? 

EdTheHeaterMan

Wet cast iron is not a problem. Think about the other side of the cast iron... there is water touching it for the entire time that the heater operates... Dah!. The ceramic fiber combustion chamber should also dry out just fine. The only problem I see, is if the water found its way into the motor on the oil burner. If that is the case, then you may need to replace the motor on the oil burner. But chances are that the motor is just fine.

You do need to fix the water leaking into the base of the chimney problem before it happens again. You don't want that to be a consistent thing. Since the water on the outside of the cast iron would be considered an open system... Since it is not a closed system. You can't expect it to last forever with fresh water flowing over the boiler every time it rains.

Jamie Hall

As @EdTheHeaterMan said, the boiler itself is probably fine, though I'd let it dry out before I fired it up. However, anything electrical which got wet should be replaced.

That said if you have water getting into the base of your chimney and getting high enough to get into the boiler, your whole house has a drainage problem...

Ahomeowner

Ed, thank you. What you said about the cast iron makes a lot of sense.  I remember years ago when we had our *old* boiler serviced, the tech was doing all kinds of vacuuming inside. There is some grit on the top of the cast iron that I can see where the flue pipe was connected, and I’m assuming that this came from the flue. Would you say that this should all be vacuumed out or would need some kind of servicing? Some of the fiberglass insulation that was on top, near where the flue pipe connected was also damaged.  I am very worried about the burner, motor and electric parts but there is nothing I can do except make sure it’s completely dry and hope for the best. I will also mention that the water on the basement floor had an oil sheen on it’s surface.

HVACNUT and Jamie,
I was not going to get too much into the chimney issue because I know it has to be fixed before I can reconnect the boiler and I have a plan for getting it fixed so my main worry is the boiler. I completely removed the flue pipe so that any water that enters the flue goes onto the basement floor and not into the boiler. I cannot show where the water is entering because it is below grade. We had the chimney inspected with cameras by an extremely reputable company when we bought the house and to make a long inspection report short, the chimney is not in great condition and I completely removed the wood burning stove and will not be making any repairs to *that* flue. However, there was a flue liner in place for the oil-fired boiler and the inspector said that that was in good condition and made that flue safe. I thought that solved the problem of a poorly constructed chimney and I hadn’t given the chimney much thought since then.  I do not believe that the groundwater is “rising up” in the chimney. I believe that below grade, the chimney is in very poor condition and tree roots may have entered and made it worse and water is entering cracks and then finding its way inside the flue liner. After removing the flue pipe from the boiler to the flue liner, I can see actual dirt and possibly roots inside the chimney (around the flue liner.) I will be digging up the base of the chimney and then calling in the same reputable chimney company to see what is involved with making it water tight, at least above/at the level of the flue. It doesn’t much matter what happens below the flue, as water travels down by way of gravity. We only have a minor drainage problem with our gutter downspouts, which I am in the process of re-routing. In addition, the downspout nearest the oil tank was damaged and I don’t think it was draining far enough away from the house due to the damage. The oil tank doesn’t help because it directs water towards the chimney. We have interior French drains and two sumps pumps in the basement and they *never* fill up or turn turn on. The problem is a poorly constructed chimney that may be decomposing below grade. All of this happened during major rain storms the likes of which we haven’t seen since owning the house, which is why I though the first time was a fluke and I actually though the water came from sideways wind-driven rain at the top of the chimney. After the second time, I realized that it was coming from below ground. I will post pictures in the interest of helping others.

EBEBRATT-Ed

You need to stop the source the water entering. The tech needs to start the boiler and run it to dry everything out. After it is dry shut it down evaluate what needs fixing clean the boiler replace parts and put back into operation check combustion.