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tankless coil in boilder question

Hoping NashuaTech is around to help. I read a post here: https://advice.thisoldhouse.com/showthread.php?55799-oil-furnace-little-to-no-hot-water

I am in north NJ and have a Weil McLain boiler-burner using oil in a very old 2-story Victorian house with steam radiators. The boiler is about 14 years old. The tankless coil is the original - surprise to many. I've had it cleaned twice when hot water was ran out too fast. I am a single person who uses hot water rarely, but can hear it kick on even when I spend a minute brushing my teeth with warm water. So I do use oil all summer to some degree. I bought this boiler when the coil in the original gigantic boiler (about a million years old) leaked and could not be replaced - I came home one day to boiling water spewing out all my radiators flooding the house with dirty water. I really don't want that again.

I was considering converting from oil to gas, but the cost is stopping me - overall $8k to $10K. Then the next thought was to simply stop using the coil and get a indirect water heater or just a standard electric water heater. What is stopping me is that the basement has no drain. My fear is the popping of any water tank and a possible flood in the basement without any outlet, or just the need to flush it every 2 or 3 years to change out the rods. People have said I really do not want to install a sump pump or free standing pump. I've heard of gadgets that can be installed to detect water leaks and will shut off the water to the water heater. Someone said if you get a new water heater when the warranty is up it should not pop - but the risk is not one I think I can take.

I've thought of just shutting off the boiler during warm weather May-September, estimate I'll save one fill of the oil tank per my buying history (about $900). Then turn it on only when a cool shower is not realistic and do laundry and run the dishwasher that day. My oil company says that would harm the boiler due to condensation build-up not being good for the cast iron boiler. But that does not really make sense given if I had a water tank the boiler would not run all summer any way.

I had the house insulated under the federal tax credit and a huge state rebate, and use a wood stove evenings/overnight in cold weather that saves me about a tank of oil - so I'm down to 3 tank fills.

What are your thoughts?

Re: tankless coil in boilder question

I should add I have hard water. When I bought this house the hot water pipe to the washing machine had only a trickle of water from heavy use by a family that did a lot of laundry. I bought a new washer about 15 years ago and it has had no problem with light use as a single person. Many valves on the boiler and around the house have had to be replaced due to leaks from the water. It does not seem hard enough to make laundry poor, and suds from soap seems ok. But I can't keep clear glass dishes and I can't stop the spotting.

Re: tankless coil in boilder question


I am very glad that you had the good sense to have the large house fully insulated; this has already no doubt gone far in putting money in your pocket on heating/cooling bills savings, and will pay dividends well into the future; I was most interested in your SECOND POST, where you described extensive problems with hard water, and the negative effects it is having on your plumbing & hot water/steam system.

Do you have a water softening system in place now?? And if so, what brand & is it a whole house system, & is it effective???

I assume you are on a well.

If you have no WS system now, you could perhaps check out the sites below for a whole house system to see if they have something of value to offer you; hard water is a real death sentence especially to hot water or steam heating systems, because the minerals clog up the boiler, the HW coil, the piping to & from the rads & the rad vents in a steam system; and if you decide to buy an indirect HWH, it will clog THAT up as well in a very short time---not to mention the boiler HW coil, and problems with water used for drinking, cooking, showers, etc.; I would definitely look at eventually buying the BEST water softening system you can find, after you have done extensive research on the issue.

No doubt most people in your town have exactly the same water problems you have, so ask around your neighborhood & check the Yellow Pages for local contractors who deal with this problem; Culligan, Safeway & Whirlpool have been in this business on a national basis for many years.

Your heating system is going to keep clogging up until you resolve the hard water problem.


Re: tankless coil in boilder question

If you have a below-grade basement without natural drainage, it is simply a pool waiting to be filled. And it will happen sooner or later from storm, flood, or accident. All of these basements need a sump pump. Now if you're on a hill where you can install a drainpipe from the lowest level sloping down to a ground outlet, that is a better option since it will always work- even without power. Most of the time you can't do this- hence the sump pump.

I don't know much about tankless coils but a recant ATOH show had Richard addressing quantity issues on a similar system. IIRC, he solved this by installing a small independent tank-type system downstream of the tankless coil. With that you would not need to have the furnace operating to get HW and the added capacity ensures you will always have enough HW when the furnace is on since it will then fill the tank with hot on demand.

Have your water tested to determine what is making it 'hard' so that you can install an appropriate whole-house softener or filter that will handle the main culprit(s) efficiently. It is not a one-size-fits-all situation unless you want to spring for a top-of-the-line system anyway.


Re: tankless coil in boilder question

Thanks. I am on a hill, so the basement will never flood and stays dry through the worst storms. I will inquire with my mason what it would take to cut in a small little drain pipe out the bottom. I have a stone foundation (boulders). A very old house.

Re: tankless coil in boilder question

Not sure how this would work (I'm not at all technical) - " installing a small independent tank-type system downstream of the tankless coil. With that you would not need to have the furnace operating"

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