# Help--cast aluminum heat exchanger is leaking through two pin holes



## Sawyer (Dec 6, 2008)

I know this is not directly related to wood boilers but I do trust the information I receive here so I thought I would ask. My son just called a few minutes ago and said his Utica ub90-200 natural gas boiler with a cast aluminum heat exchanger is leaking through two pin holes. I would like to get some possible directions to help him with this problem. I am driving to his house today and will check responses along the way when possible to get an internet connection.

Does this mean that the boiler is trash? 
Is it cost effective to replace the heat exchanger or is it usually best to replace the whole boiler? 
Can it be repaired by welding or another method? 
Do any of the liquid weld patches work? If so which ones, even if only a non-permanent short term repair to buy him some time to find a good permanent solution.
It is a 2005 model and possibly would have a part only warranty coverage.

Thanks, George


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## in hot water (Dec 6, 2008)

Certainly talk to Utica, and or the rep.  Check the ph of the fluid in the boiler.  Aluminum block boilers are very sensitive to ph.  The manual should indicate the acceptable range. 

 Most manufacturers will work with you if the boiler is a bit out of warranty range.  Hard to find one that will cover labor, unless you are a prefer or large, sometimes vocal  customer.

It takes a special glycol (antifreeze) in aluminum boilers, also.  A hydronic glycol with AL in the name.  Although the inexpensive AL (aluminum) glycols have been known to offer less protection.

I'd like to see pictures of the block if you can get some.  Mainly the location of the pinholes.  I work with a chemical blender that formulates cleaners, inhibitors, and glycols specifically for aluminum block boilers.  I built him a heated coupon rack to test the various fluids in the market place.  I've seen samples of what "off ph" fluid can do to aluminum in a very short period of time.

 hr


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## heaterman (Dec 6, 2008)

Ditto on the water quality for boilers or virtually any other closed aluminum vessel containing fluid. The water chemistry has to be watched on a very regular basis. Would you by chance know if the boiler was filled with city water, possibly chlorinated? Or is it well water? Was the system PH ever tested prior to being put into use?

PS: You could post the info at www.heatinghelp.com and see what feedback you get. Lot's of very good boiler guys there.


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## Sawyer (Dec 6, 2008)

Thanks for both of you comments. 

The house was not new when he bought it so he has no information on the installation and treatment process. I know this is not good. There was not any antifreeze solution information or partial bottle left behind so we have no idea if it was AL approved or not.

Is there a test kit I can purchase at one of the big box stores that would be in Mpls.? or where else could I possibly think of checking on a Saturday afternoon. That is assuming I can make it to Mpls. as we are in a white out, lake effect snowstorm at this minute. If I can get a test kit I will post the results. Utica did say that city water was OK but I would question also.

The leak appears to be small at this time. He does loose pressure overnight. I would still hope there is a temporary repair that could be done today if possible although I do realize one would not want to contaminate the entire system doing so.



Utica Piping Recommendations
• All system leaks must be repaired immediately. Constant introduction of make up water will introduce dissolved oxygen,
  resulting in accelerated boiler corrosion.

Water Chemistry:
• System fluid pH must be maintained between 7.0 and 8.0.
• Maintain water hardness below 7 grains hardness.
• Filling with chlorinated fresh water should be acceptable since drinking water chlorine levels are typically less than 5 ppm. Do not fill boiler 
  with water containing chlorine in excess of 100 ppm.

Aluminum Safe Antifreeze, Treatments
and Additive Guidelines:
Antifreeze, if needed, must be of a type specifically designed for use in closed hydronic heating systems
and be compatible with type 356 T6 aluminum at operating temperatures between 20*F (-6.7*C) and 250*F (121*C).


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## Sawyer (Dec 6, 2008)

Leak Close-up.


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## Sawyer (Dec 6, 2008)

Bondo said:
			
		

> Ayuh,...
> 
> If you can find it,... (I've found it available thru Sid Harvey heating supply parts...)
> Dose it up with a Qt. of Water Glass....
> ...



Thanks Bondo, my son is checking availibility as I type. We will be leaving but he will monitor this thread from his house.


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## Sawyer (Dec 7, 2008)

Bondo said:
			
		

> Ayuh,...
> 
> Water Glass is also used to finish Concrete,...
> 
> That might give you another avenue to find it...



Thanks again,

My son will check with his concrete contractors and the Utica distributor tomorrow. When I looked at the leak last night, the stream looked like a cobweb when the circulator was running.


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## in hot water (Dec 7, 2008)

a small punch can sometimes "peen" a pinhole shut.  Check with Utica before you add sealers, it may void the warranty.  if it has thin casting areas, you will want a new HX.  The HX should have a 10 year or longer warranty?

 hr


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## Sawyer (Dec 7, 2008)

in hot water said:
			
		

> a small punch can sometimes "peen" a pinhole shut.  Check with Utica before you add sealers, it may void the warranty.  if it has thin casting areas, you will want a new HX.  The HX should have a 10 year or longer warranty?
> 
> hr



Thanks hr, He will definitely check with Utica before adding anything.


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## rickh1001 (Dec 8, 2008)

Sawyer, 

 I read your post earlier, then by chance wound up at Lowes, walking through the plumbing section.  Son of a gun, but over by the baseboard heaters and boiler/furnace items, they had bottles of boiler stop leak - I forget the exact name.  It was in white liter bottles, and was designed for stopping boiler leaks.  It contains silicates, so you could probably accomplish the same thing with the silicate/waterglass mentioned.  Or just head to a Lowes, and pick some up.  

Good luck.


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## heaterman (Dec 11, 2008)

Did you ever get in touch with Utica on this and if so what did they say?


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## jebatty (Dec 11, 2008)

JB Weld makes a putty product that could work well to seal any leaks. A friend of mine used it on his old steel boiler, worked well.


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## Sawyer (Dec 11, 2008)

Utica told my son to contact the distributor. The distributor put him in contact with a Utica dealer/plumber. The dealer is going to arrange a mono block replacement. Three hours labor will be my son's responsibility. I will know why it failed when they replace the mono block. The plumber doubted the original installer used the wrong antifreeze/sealer. If he did there is recourse. I will follow up when the replacement is finished. I will ask my son to get photos of the interior if possible.


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