UB90-100 Leak at bottom of HX

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Jjvirginia

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Came home two nights ago and found a small puddle on the floor at the corner of the boiler. Boiler was installed in 2008, not quite 14 yrs old. First 5 years the tech who installed it maintained it, then he left the company. Back when this was installed, there were many opinions about antifreeze in the system, and I think the tech was told by home office not to add glycol.

I flushed all my zones every other year, full turnover of the water as that is what the tech told me to do to maintain proper PH. I'm on a well and iron is 14 grains and I bring that down to 2 with a water softener.

Now I read antifreeze is required for aluminum HX. I can't tell if the leak is a pin hole in the metal or a blown gasket as the leak is close to the mating surfaces of the HX and since it is on the bottom, I can only see so much with my inspection mirror. I'm losing about 1.5 pints per day. Tonight I tried JB Weld StickMetal, scuffed up the surface with wire wheel, and the stuff kept falling off - garbage. For now, I have Permatex HT applied which has stopped the leak.

I am pretty good with turning wrenches and cleaned my boiler each year for the next 6 yrs, including removing the condensate trap and brushing out the fins once I lost my good tech. I have a new company servicing it now because it makes things easier as my time is limited, and the cost of servicing is reasonable.

I am considering replacing just the HX and I would like to do this job myself and then have a company come in and pump antifreeze in the system (PH is currently 7.8). I have a pool and some very good testing kits.

I realize the warranty on the new HX would be out the window and I'm fine with that. I don't like the idea of putting in another aluminum HX because I had doubts 14 years ago when I pulled the trigger on this unit but I'll only be in the house another 5 yrs max.

Is it possible to buy just the HX, and if so, do you think any dealer would sell me one knowing I plan to install, what do these things cost? Or should I just bite the bullet and pay $5k for a replacement unit with installation? Trying to determine the cost of different options. What if I have a tech come out and replace the HX if they won't sell me one, expected cost of this?

If I do go with a new unit, I would prefer to stay away from aluminum. I would like to stay with a condensing boiler since my annual propane bill dropped from $5,200 to $2,800 when the old cast iron WH spilled it's guts out on the cellar floor 14 yrs ago.

Knowing the above, is stainless steel a better option in terms of reliability? I know I lose a little on the heat transfer side but I am not sure I want another aluminum HX if I go with a new system.
 
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John Gayewski

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Came home two nights ago and found a small puddle on the floor at the corner of the boiler. Boiler was installed in 2008, not quite 14 yrs old. First 5 years the tech who installed it maintained it, then he left the company. Back when this was installed, there were many opinions about antifreeze in the system, and I think the tech was told by home office not to add glycol.

I flushed all my zones every other year, full turnover of the water as that is what the tech told me to do to maintain proper PH. I'm on a well and iron is 14 grains and I bring that down to 2 with a water softener.

Now I read antifreeze is required for aluminum HX. I can't tell if the leak is a pin hole in the metal or a blown gasket as the leak is close to the mating surfaces of the HX and since it is on the bottom, I can only see so much with my inspection mirror. I'm losing about 1.5 pints per day. Tonight I tried JB Weld StickMetal, scuffed up the surface with wire wheel, and the stuff kept falling off - garbage. For now, I have Permatex HT applied which has stopped the leak.

I am pretty good with turning wrenches and cleaned my boiler each year for the next 6 yrs, including removing the condensate trap and brushing out the fins once I lost my good tech. I have a new company servicing it now because it makes things easier as my time is limited, and the cost of servicing is reasonable.

I am considering replacing just the HX and I would like to do this job myself and then have a company come in and pump antifreeze in the system (PH is currently 7.8). I have a pool and some very good testing kits.

I realize the warranty on the new HX would be out the window and I'm fine with that. I don't like the idea of putting in another aluminum HX because I had doubts 14 years ago when I pulled the trigger on this unit but I'll only be in the house another 5 yrs max.

Is it possible to buy just the HX, and if so, do you think any dealer would sell me one knowing I plan to install, what do these things cost? Or should I just bite the bullet and pay $5k for a replacement unit with installation? Trying to determine the cost of different options. What if I have a tech come out and replace the HX if they won't sell me one, expected cost of this?

If I do go with a new unit, I would prefer to stay away from aluminum. I would like to stay with a condensing boiler since my annual propane bill dropped from $5,200 to $2,800 when the old cast iron WH spilled it's guts out on the cellar floor 14 yrs ago.

Knowing the above, is stainless steel a better option in terms of reliability? I know I lose a little on the heat transfer side but I am not sure I want another aluminum HX if I go with a new system.
Yes stainless is better. You've lived the full life of a mod con boiler. Think about selling your house. Would you rather say the boiler is less than 5 yrs old or say yeah the boiler could go at any time?

Just my opinion.
 

Fitter30

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Manufacturers make older parts expensive so they don't have to stock inventory. Probably be almost cost as much as a new boiler and only 1 year warrantee.
 
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