When Pipes Freeze - Part 1

Really, this post should be titled… “Is A Smart Home Always Better?!" Or something that hints to the betrayals of new technology. But in reality, we all know there is no such thing. New technology didn’t betray or fail me. I let new technology take over a simple function of “switching on and off” and what ensued was a big FAIL on my part. Get ready to geek out on HVAC knowledge.

Our Home and How I Love My Boiler

Let me provide some background and context - we own an 1894 Grand Victorian in the heart of central Oak Park. The home was originally built with a gravity heating system. Simply put… a coal fired furnace in the basement heated a pot of air that would then rise through large ducts to various rooms in this 2 story home thus heating the space. Then… in the mid-1940’s, the home owner had the funds to remove or convert this furnace to hot-water boiler heat; an oil burning boiler would heat water to about 150F and a pump would circulate the water throughout an open pipe system (one large circulating system with no zone shut-offs anywhere) of “supply” (the pipe that brought the water to the radiator) and “return” (the pipe that brought the cooler water back for more heating).

I love this type of heat. It is quiet, even, and less dry than a forced air system. Since day one of owning this home (almost 18 years) the system has been flawless with minor part replacements on a Burnham boiler that was installed in 1999. At the beginning of every annual heating season I need to take a couple hours and fire up the system… make sure the boiler’s water pressure is just below 12lbs per square inch and go to each of the 2nd floor radiators and using a special key open the vents to release the pocket of air from the tops of the radiators so that each radiator is full of hot water. Most people that have this system of heat (very popular in this area) don’t realize water actually evaporates from the system. This creates air pockets in the radiators thus a less efficient heating unit if only half the radiator heats. In the early morning hours of Wednesday the 3rd of January 2018 the outside temperature reached a low -9F.

Happy New Year to ME!

At approximately 10:30am after returning home from visiting my doctor for a nasty hacking cough, my wife, Julie, announced to me that one of the radiators in our master on the 2nd floor was… cold. (It is from this moment forward that I will now know that a “cold” radiator in the dead of winter can only mean one thing… inevitable catastrophe.)

I immediately went to the basement. I am an HVAC nerd and pretty much pride myself on the fact that when I open a boiler’s cover panel… I know what I’m looking at. I removed the panel and checked the water pressure gauge. Zero pressure. “Hmmm… that’s not good”, I thought.

pressure gauge-1.jpg

Because water needs to occasionally be put in the system, all boilers have a fresh water-fill supply coming into the system usually close to the boiler. Most systems have a pressure control valve. This is a flying saucer-looking thing attached to the fresh water fill pipe that automatically senses the water pressure. When the pressure reaches a certain point, it will shut off the water for you, constantly monitoring the pressure and always keeping it at the right level. I NEVER LET THIS AUTO PRESSURE VALVE BE THE ONE TO AUTOMATICALLY MONITOR MY WATER PRESSURE IN THE SYSTEM!!!!

There are just too many chances for failure here. They don’t always work and if it fails when you are not around it can overfill your system and cause the boiler to blow its pressure relief valve all over the floor thus releasing the pressure in the system. BUT then what does the auto pressure relief valve do?!?!? It keeps filling!!!! So, in the fresh water line just before the pressure refill valve I have a hard shut-off ball valve that I always keep in the off position unless I am filling the system and standing right there.

auto fill valve-1.jpg

Holy Calamity 

So… I see ZERO pressure on the gauge and I instinctively reach up to the ball valve and turn on the water feed. At that instant, about 12ft away, water starts POURING down the inside foundation wall directly under the living room. In the photo below you can see the magnetite (boiler heat sludge) stained limestone and brick foundation where the water poured out of the burst 90 degree cast iron elbow.

Panic sets in!!! I shut off the water feed. The sludge continues to pour down the wall, but to my relief, eventually subsides. Even with the system being open and no zones to isolate the leak, the system is still able to heat for another couple hours until I fear there is too little water in the system and the cycling on and off may do more damage. Julie and I shut down the heat.


Launching an HVAC Investigation

So what happened? In all of our almost 18 years of ownership we have never had a broken or burst heat or water pipe. Why now? Why not during the Polar Vortex of 2014 when it regularly got below -5F for weeks?


A few years ago I updated the system’s thermostat to a new Wi-Fi based NEST thermostat. Wi-Fi___33 meaning you can control the thermostat from an app on your computer or phone. I got it so that when out of town I could see how the system was performing and basically make sure it was running. About 2 weeks before this holiday season something changed. The NEST asked us a question.

 “NEST and your gas service provider have partnered to help you save on your energy bill. Turn on “Auto-Scheduling” to start.”

 Basically, the NEST was ready to start learning our habits or our at-home, away and/or sleep… schedule. So we turned on the auto-schedule and the NEST notified us that over the next two weeks it would be learning our ways.

The schedule seemed to be working fine… nothing earth shattering changed. We did start to notice that it would get chillier in the middle of the night. The NEST was noting when we retired to bed and would drop the heat from about 67F to 64F for a few hours, gradually bringing the heat back up to our wake-up time. Sounds like a good energy saving idea! Ah technology, what would we do without you? Maybe get back 3 days of my life that was dedicated to fixing this issue!!!

 I digress. So with this auto scheduling came the perfect storm of the following factors on the night of January 2nd into the 3rd.

  1. When the hot water heat system was installed in the 40’s they busted through the top brick portion of the foundation to get into the outside wall cavities to run the vertical supply and return pipes (risers) to the radiators on above level floors. In the above photo you can see the dark hole where the pipes enter the basement wall.

  2. The home was built with a front porch that rotted and fell off in the 30's. This porch had support beams and these beams had the foundation built around them where they entered the house for anchoring purposes. When our contractor in the early 2000s tore off the asphalt siding he uncovered these open holes in the foundation. At that same time he rebuilt a new porch to be just like original. But that only covered the holes from site as the new porch used a sill board to tie into the house. The other holes remained and they opened right into the first outer wall cavity.

  3. The home was not built with any insulation in the exterior walls. Julie and I had a company blow in insulation in the early 2000s. This insulation could not reach everywhere and the lower cavities where the heat pipes entered the walls had fire blocking boards just above where they entered so the initial 1 sq ft cavity above the foundation was not insulated.

  4. The boiler’s pump that circulates the hot water to the radiators and back has a temperature switch. Once the water in the outgoing pipe hits 90F, the switch turns the pump on and circulation begins. If the temp in that pipe falls below 90F, the system knows there is no need for heat and the pump does not circulate thus saving electricity.

Finally, it all came together.

  • The temperature outside dropped to -9F, the wind howled through the still open holes from the original porch super cooling the 1 sq ft cavity in the outer wall where the cast iron heat pipe had a 90degree piece to run heat up the wall.

  • Then, the NEST sensed I went to bed at midnight… the temp at that time was 67F in the house. The NEST dropped the heat to 62F! Basically shutting off the system for more than 3 hours. In that 3 hours of no heat and the water in the system sitting idle (no pump on to circulate), the elbow piece froze and the force of the water expansion blew the cast iron sidewall of the elbow completely off. Catastrophe…


More to This Story...

Stay tuned for Part 2 of this New Year saga when I have to make the decision as to who am I going to call to repair the burst pipe and get the heat going again before the whole house freezes and we have a real problem. In Part 2, one of the most intelligent contractors I have ever had the privilege of working with comes to the rescue and the repair becomes a family affair.