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Water in combustion chamber?

Sethamin Member Posts: 58
Been trying to get the heat working in a foreclosed home I just bought. It has an oil fired Weil Mclain Gold boiler with forced hot water serving baseboard radiators.

I had an HVAC company come out, they installed a new burner (Riello 40 F5) and a new combustion chamber, cleaned everything up, and got the boiler up and running. But I couldn't yet turn the heat on because all the circulators had seized up, as well as the boiler feed valve/PRV. The tech assured me that the boiler itself was running fine, and it was just those parts that needed to be replaced to get the water flowing. And it did seem to be holding its internal temperature around 180 for a few days (with no water circulating, of course).

HVAC company wanted too much money to replace all those parts, and this was getting really expensive, so I decided to do it myself. I powered down the boiler just in case I had to drain it (which I didn't - isolation valves on everything). Fast forward a few hours, and everything is installed, so I fire it up and again and let it rip. Simultaneously three things happen:
  1. Water starts leaking from one of the flanges of the circulators (gasket fell out while I was installing it)
  2. I discover a burst in one of the hot water lines that I had previously not seen
  3. Water starts coming out of the bottom of the burner (!!!)
I took a quick peek inside the combustion chamber, and I could see a significant spray of water coming from the upper left. I shut everything down after that. The first two were straightforward to fix, but obviously #3 is the most concerning to me. What happened? It seemed like everything was fine prior to me shutting it down and firing it back up again. Why was there suddenly a spray of water in my combustion chamber after that?


  • lchmb
    lchmb Member Posts: 2,997
    edited April 2018
    sad to be the bearer of bad news..but sounds like moving water caused it to fail... with everything you've mentioned, it may have been less expensive in the long run to do a full replacement... You should be able to get the boiler minus the burner but it may be a better option to upgrade to a 3 pass boiler.
  • Sethamin
    Sethamin Member Posts: 58
    I was afraid of that. I don't suppose there's any chance it's just a defective combustion chamber or some seal that's fixable?
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,132
    edited April 2018
    Nope. It probably froze and cracked/warped a section. You could replace the sections, but it may cost more than a new boiler when it's all said and done. The tech who put in the new burner did you a dis-service, based on your situation by not filling and checking the entire system first.

    For others who stumble upon this post, if you take over a foreclosure, assume it all has to be replaced. In the scenario involving the OP, I wouldn't let a company come out and do any component or mechanical repairs until they filled the system completely, pressurized, and checked for leaks.
    You don't need water circulating to fill and bleed the system. If the feed wasn't working, with a washing machine hose, and a regular hose (or double female hose fitting), and you can fill the system from a hose bib, or if the hose can screw onto the faucet spout, an older laundry sink. That would save you a lot of time and eventually money replacing/fixing components.
  • Sethamin
    Sethamin Member Posts: 58
    To be fair, they did fill it manually and it was holding (both pressure and temperature) for a few days. It wasn't until I started up the circulators that the section appears to have cracked. But the point still stands that given the fact that almost everything on the boiler had to be replaced (circulators, feed valve/PRV, relief valve, oil burner, combustion chamber, pressure/temperature gauge), they probably should've figured that the boiler itself needed replacing, too. Or at least they could've recommended that I replace the boiler given the amount of money required to get the old one going.

    On a related topic, can anyone recommend what type of new oil boiler I should look at? It's a seasonal house, so in the winter it'll just be set to the minimum to keep everything from freezing (which means efficiency is probably not paramount). The house is currently set up with forced hot water to baseboard radiators, but we may do a big renovation a few years down the line, add some square footage, and convert everything to radiant (my wife has an irrational hatred of baseboard radiators). Is there a type of boiler that could handle both cases well?
  • unclejohn
    unclejohn Member Posts: 1,830
    I have had two WM leak on me only to stop a few days later when I returned with the rep on one and got a call from the home owner on the other.
    HVACNUT Member Posts: 5,025
    A cracked heat exchanger means a new boiler. However, all the new parts sans chamber can be used on your new system (or as spares). Riello has a retrofit manual for most brands.
    Like @Ichmb said a 3 pass CI boiler Buderus, Trio, etc. with an indirect water heater. Or look into Energy Kinetics System 2000.
    Efficiency may not be paramount, but getting a reliable heating system and the right contractor is paramount. Have a heat loss calculation done and weigh in the renovation.
  • SuperTech
    SuperTech Member Posts: 1,919
    If you are going to replace the boiler and keep the house long term, you might as well get a decent one. For oil fired boilers with radiant heat an Energy Kinetics System 2000 or a 3 pass Buderus or Viessman is nice. Proper sizing and installation is a must.
    EBEBRATT-Ed Member Posts: 13,440
    Did you have all the valves open when you started it up? Does the boiler have an operating relief valve? Too bad that happened
  • Sethamin
    Sethamin Member Posts: 58
    Actually the return valve on one of the zones was closed when I fired the boiler back up. I opened it pretty quickly, but I think the crack had already developed at the point. Do you think that stressed the system and was the catalyst for the section cracking?
    EBEBRATT-Ed Member Posts: 13,440

    If the boiler was ripping hot and the returns were suddenly opened and brought back cool water it could cause a problem. Dosent sound like that happened from your description.
  • Sethamin
    Sethamin Member Posts: 58
    Actually, I think thermal shock that could at least partly explain it. Water in the boiler was still warm (though not hot) when I opened the feed valve to repressurize everything, and that probably dumped in a bunch of cold water. And it was right after that point that the section cracked.
  • Zman
    Zman Member Posts: 7,446
    I suspect it was damaged by the abuse it took during foreclosure. You just triggered the demise.
    Cast iron boiler are very robust.
    Check the sizing and pick up a new one.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    SuperTechdelta T