Tankless Coil on a Heating Boiler Leaking

pepperidge_farmJanuary 17, 2009

We have a Utica oil furnace with a tankless coil, that was installed in 1992, that has a leak near the top of the faceplate.

We have to get someone in to repair it, but the obvious concern is whether or not investing in the repair is worth it, as we do not know what shape the coil will be in once it is pulled out, etc., we have fairly decent well water. If the repair is costly, perhaps repair is short sighted and we should consider replacement as it is 17+ years old?

As it is over the weekend, I was hoping to get some concept of the cost of such a repair. We do love the tankless coil and the endless hot water, it has been working fairly well. I have lived with tankless coils that were a real pain, I think I recall something called "boil a coil" that used to have to be put in.

So, we are in North NJ. Any rough ideas of a range of cost just to begin such a repair? What about a similar replacement (or similar solution for oil)??


ps I do realise there are endless variables here, just looking for a starting point among the endless possibilities!

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I've seen ripoffs to the tune of $600 for replacing a coil. Chances are you can either replace the gasket or maybe even snug up on the bolts/nuts. Don't let anybody convince you to replace a perfectly good coil when a gasket will do. Coils can last the lifetime of the boiler if the water is good.

    Bookmark   January 17, 2009 at 10:37PM
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Cost depends on what's wrong and degree of difficulty. We can replace some coils or gaskets rather quickly, but others are difficult when the boiler is in a tough spot, when the piping needs cutting & soldering, or when bolts are broken or stubborn.

We check and tighten tankless coil bolts on annual service and/or clean and replace leaking gaskets. The majority of the time leaks are caused by loose bolts, crud on the coil gasket, bad coil gasket or leaking fittings. Often the leaks occur in the off cycle. When the boiler heats up, expansion and heat are enough to seal and/or evaporate small losses of water.

By checking and re-tightening bolts on an annual basis, the bolts less likely to snap when you have to replace the coil.

I personally wouldn't put a lot of money into an old inefficient vertical pin boiler.

    Bookmark   January 18, 2009 at 8:43AM
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Replacement coils for most boilers are manufactured right in Blackwood NJ. Finding an aftermarket replacement coil from a good installing contractor shouldn't be a big problem if needed.

    Bookmark   January 18, 2009 at 12:22PM
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Thanks for all of the above , I appreciate and agree with the sentiment of markjames regarding putting money into an older boiler!

We did tighten up the bolts last year, there was a small leak- completely resolved, and then just as the weather got super cold and the boiler was working more than usual the leak started again in earnest. When we tried to retighten, didn't really help, and it appears that the gasket which is visible from the side looks like it is not completely intact/cracked. The bolts don't look obviously in bad shape, so that is one plus.

The boiler is not in a tough spot, but I can't imagine that there won't be pipe cutting involved with the job.

If it looks like it is under $1K, I think it is worth the repair, so that is reassuring. I don't think that for the age, I would be willing to invest much more than that in it.

Grateful for the input!

    Bookmark   January 18, 2009 at 12:41PM
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Markjames mentioned that water will evaporate around the coil. This is the silent death of many boilers. It may evaporate but it's still rusting away. It's common to weld coil patch plates over the rusted out area to save an otherwise good boiler with a rusted coil area. Companies that manufacture quality boilers have these in stock. You'd be surprised how many we sell for boilers that are over 50 years old.

    Bookmark   January 18, 2009 at 4:23PM
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Yes, air is the silent killer. We see a lot of new installations with leaking fittings, valves, circulator flanges, soldered/threaded connections and gaskets (usually pumping on the return side with a crappy air scoop and float valve)

Besides introducing air/rust into the system, the leaking water and rust make the new system look like garbage and often drip on electronic parts.

We remove coils & install blank plates, or cut out the coil & plug the tappings since many customers have installed indirect or stand alone water heaters.

The tightly wound, small diameter tankless coils in vertical pin boilers plug easily and few companies acid flush anymore.

The efficiency of the coil is also greatly reduced when it's loaded with minerals.

Some of the larger diameter trombone style coils on tube style boilers are still functioning well after decades of use.

The first twist on the the bend of some small diameter tankless coils is so sharp, that it loads up with mineral deposits in a matter of weeks with some water conditions.

    Bookmark   January 19, 2009 at 10:38AM
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You have given me some tools in the conversation I will have this week with person that finally shows up to look at it.

Just the info I need to ask the right questions!


I'll update when I get some info. I have lived with some troublesome coils, but I have to say I have been really pleased with this one-- and we are on regular old well water (although it isn't bad, still well).

    Bookmark   January 19, 2009 at 8:19PM
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If I were you, I'd just have the tankless coil part permanently sealed and switch to either an indirect tank or a standalone unit.
Tankless coils are horrendously inefficient when used with a boiler during non-heating season, which for you is half of the year. The standby losses of a big, hot boiler are terrible and you may find that it sucks down hundreds of gallons of oil during the summer. The waste heat usually finds its way up into your house, meaning more air conditioning and greater operating cost wastage.

My preference is to use a different, highly insulated system for water heating so that I can turn the boiler completely off during the off season. Even with an electric heater, you'll save money due to the above factors. Or, once GE comes out with their heat pump water heater, you can go that route.

    Bookmark   January 19, 2009 at 11:14PM
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Hundreds of gallons for summer use? Hardly. I have personal experience with this issue, besides working for a manufacturer of quality boilers.

For almost 30 years, I used a medium sized, cast iron, boiler for just one purpose....domestic hot water for a family of five. We started heating with wood immediately in 1977 and never used the boiler for the baseboard. Over a 30 year span, we used approximately 250 gallons per year, each and every year. When oil went up to the high one dollar amount, I called PPL and tried to determine if it would be cheaper to go with electric hot water.....it wasn't.

An indirect hot water tank loses 1/2 degree per hour standby, compared to maybe 5 degrees in a boiler, so they are a good way to go. There are two methods of construction on indirects. The one I would use would be the Ergomax. Compare that one with the others that run boiler water through the copper coil.

    Bookmark   January 20, 2009 at 11:40AM
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Every system with a tankless coil that I've analyzed has run through 200-300 gallons of oil during the summer months, regardless of family size and claimed water use, my own New Yorker, included (now replaced). They sit there, spilling heat into the house, cycling on and off, they're horrible and should be outlawed for this purpose. In real use on my New Yorker, I found an actual system efficiency of about 25% when running over the summer, and it was all checked out and running at a claimed 80+% efficiency.

Whatever you've got in your setup, you're doing a LOT better than any I've ever seen in the field.

    Bookmark   January 20, 2009 at 2:52PM
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Not trying to cause any trouble, but those are the facts. And the consistency over 30 years is the proof.

    Bookmark   January 20, 2009 at 4:36PM
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OK, to modify the topic a little :-) I have another question...

Does an indirect water heater also supply unlimited hot water... I really haven't looked into what those are and how they work at all as I am hopefully not going to need to be in the market for a big purchase!

    Bookmark   January 20, 2009 at 10:20PM
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If the coil design is like an Ergomax, where boiler water surrounds a coil, you will probably never run out of hot water. If the boiler water flows through the coil and is surrounded by cold water, yes, you can run out of hot water. You can also develop a leak in the outer jacket.

Their claim to fame is the low loss of heat in standby, which is true in both designs. You still need a boiler or some device to maintain temperature.

    Bookmark   January 21, 2009 at 6:30AM
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"Does an indirect water heater also supply unlimited hot water."

Depends on your hot water demand, BTU of the boiler, boiler mass, size of the indirect(s), supply water temperature, boiler supply temperature, boiler piping, circulator, flo-checks etc.

I never run out of hot water at my primary home (6 bedroom, 6-1/2 bath, 2 washers) although my wife, 4 teenage daughters and their friends use hot water like it's going out of style.

I have several different brands of indirect water heaters (Buderus, Veissmann, Triange Tube, Bock, SuperStor) at my homes, apartment buildings, businesses and investment properties and have rarely run out of hot water.

I sized my boilers to the heat loss of the structures, put the indirects on priority and oversized the indirects slightly for dump load purposes.

    Bookmark   January 21, 2009 at 9:36AM
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Years ago, Real Life Adventures comic strip had a picture of a worried homeowner looking at the plumber pulling up in his Rolls Royce. Now we know his name. :)

    Bookmark   January 21, 2009 at 11:24AM
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OK, so yes and no... we are in process of installing a fair sized (can't remember the total volume right now) air bath, and wasn't sure a tank system would be adequate if I need to reassess my needs. We considered our current system when planning...
Yes, teen boys like long showers too!

With regard to a previous comment, our boiler is actually located in a great spot- there is a structural small porch that has a full basement underneath it, so although it may warm the finished basement next door, it never does in the summer- it is the coolest place in the house, and the area above it is outdoors! Seems like it was very well thought out during construction back in the 50's.

    Bookmark   January 21, 2009 at 11:51AM
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I have a tankless coil in a boiler. They say I require a new valve to do a chemical cleaning. How much in the northeast should a cleaning and valve added cost?

    Bookmark   December 6, 2011 at 7:30AM
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