Cast iron boiler failures

Joe_10

And lots of calcium buildup in water ways about 1" of loose material and water is clear with no signs of rust. So now i am trying to figure out how to eliminte the calcium buildup in the system.
Joseph

Joe_10

leaking HX in Weil Mclain cast iron

I Have a client who has a home that was designed with solar as primary heating via 320sq. ft. of collectors into about 1000gal. (well water) storage which then heats the home. A propane fired boiler was added to provide backup heat. It was a Weil Maclane CG3(s?) yr1981. Which failed fall of 1987. Somebody replaced it with same size boiler which failed in winter 1993. Next contractor then replaced with a CG5 but kept the 4" type B vent this boiler failed this week. The original installer used a stripped 40gal water heater as an expansion tank which sits on the floor with the boiler in the basement of the house. The CG5 is the correct size for the needed Btus. There are no leaks in the system the expansion tank becomes water logged and has to have extra air added to keep pressure from building. There was added with 3rd boiler an air scoop along with a #30 expansion tank.( previously no air removal stystem) Zone valves with an aquastat control whether the boiler operates or not.
My plan is to use an induced fan boiler through the 4" vent and set up a primary and secondary loop system to help protect the boiler from the colder water of the system. The solar runs until storage is 110 fahrenheit. Am I missing anything or is there a better way to do this? There is the possibilty of using a sealed combustion boiler as there is access to an exterior wall with clearnce above ground. However HO just had house restuccoed and would prefer not to penetrate the new stucco.
Thank You
Joseph

hr

When you say failed

how are they failing? Cracks, leaks? First I would suspect they are running in the condensing mode for long periods of time if they are connected to that 1000 gallon tank without adequate return temperature protection. That boiler should not see extended run periods of below 130 degree return temperatures. My opinion is within 10- 15 minutes it should be running 130 return. You may need a better boiler piping arrangement that provides protection for the boiler.

The tekmar 369, I believe is a popular control to use with solar/ boiler arrangements. It provides two reset functions using VS pumping or motorizied mix valves. Really need to see an accurate piping drawing to say for sure.

Another option would be a condensing type boiler that would be un affected by low return temperatures.

hot rod

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Dave Holdorf

O2 permeation?

May be the culprit. How is the solar system hooked up and what type? Does the water look like an excessive amount of rust?

Might need a heat exchanger to isolate.

Dave H.

Dan M

Weil Mclain

My first Weil-Mclain GV5 Lasted about 6 years. It started shuting down 2 winters ago and I had a service guy Check it out. I am not sure exactly what happened but the boiler was breaking down internally. No reps from Weil Mclain ever came to my house but they felt the boiler may not have been installed properly. My new service man ( Not the original installer) got the impression from phone conversations with the Weil-mclain rep that there may have been problems with this type of boiler. When the new boiler arrived it was a GV5 but had apparently been re-designed significantly. Two internal circulator pumps were added to better control hot and cold water mixing in the boiler jackets , The exhaust pipe Flange which used to have one corner bolt and leaked badly now has four. The new boiler would not circulate water with the original circulator pump , it was replaced with a larger model that makes alot of pipe noise and vibration in the house. As a home owner I am out of luck because weil-Mclain will not provide tech support to a consumer. I paid a lot of money for what i beleived was the best in the buisness as well as a $1700 cost to evailuate the old and re-install the replacement boiler. At this point I have been left with a poorly preforming heat source that makes a lot of noise.