Confused about Megastor

Tekkie

Now I learned something! My coil is restricted too and some people have had acid run through to open theirs up. I have not had to do that yet. It is another consideration I guess that I will have to take into account when I get my 39 year old setup replaced.

Joel M

Megastor

Presently I have a Weil McClein boiler with a coil for hot water. We noticed it dosent produce hot water like it did 12 years ago. The tech who does the yearly service on it say's it is because mineral deposits are on the coil reducing the output. He suggested the Megastor 40, said he has one and it is great. I am concerned that if the coil in the Weil has mineral deposits, wont the coil in the Megastor eventually get them? We have city water. Thanks for any suggestions or advice.

ed wallace

megastor

mineral build up on the megastor ciol will be les of a concern since it will be the water from inside the boiler that is piped thru the coil the domestic hot water will surrond the coil plus mega stors have a inspection hatch on the top so megastors can be inspected and cleaned if needed

Joel M

Isn't that the same? The Weil coil is surrounded by water, I don't understand why the Megastor woild not have the same problem eventually.

heatboy_2

Tankless coils.......

....... are always finned copper. Lots of places for debris to accumulate. The MegaStor, on the other hand, is a smoothwall stainless coil. It is very difficult for debris to stick to it. Also, as the coil inside the tank heats and cools, it will flex.

Joel M

Wow, I never knew that. I thought they were smooth. Thats why we ask the experts! Thanks for both replies.
Joel

ed wallace

tankless coil

personally i would never run acid thru a tankless coil would rather install a new coil or a storage tank

heatboy_2

Several Issues with tankless coils.........

...... and they show the same thing. No hot water. If it is debri on the outside of the coil, there are hydronic cleaners and inhibitors that can aid in cleaning the coil without actually removing the coil, which will cause it's own set of problems. If the incoming water is mineral rich, the minerals will cook out inside the coil and cause a flow restriction on top of the designed pressure drop of the coil. In the past, I have acid cleaned hundreds of coils with varying degrees of success and failure. If the coil needs to be acid cleaned, it's time for water treatment.

Add a mixing valve to the mix and it can get complicated trying to figure out exactly what is wrong.

I don't like tankless coils very much. Can you tell?

scrook_2

coil scale

The W-M coil is surrounded by benign (because it is never changed) boiler water, but accumulates calcium (lime) scale on its inside (due to the water's hardness) of the municipal water that passes thru -- this also tends to clog it.

The megastore is opposite, boiler water inside the heat exchanger tube, fresh domestic water outside, though, like *ANY* water heater (electric heater element, bottom of a gas heater tank, heat transfer coil, etc.), the heat exchange surface, on the domestic water side, will eventually accumulate scale.

An acid flush will remove the scale, though it may also pinhole the coil or the coil may later develop a leak to the boiler water side.

hot_rod

smooth surface coils

do tend to perform better in hard water conditions. The fins on heat exchange surfaces make for more heat transfer surface, and with ideal water condition they work great.

Also the higher the temperature through the coils the faster the minerals precipitate out of the water and and cling to the surface. Maybe that is another reason why the Germans limit the boiler output temperature to 167

Hard water build up is clearly seen with electric water heater elements. The small surface area type of elements usually have the shortest life. The Sand Hog is a good example of an extended life element with lots of surface area.

Still, the best solution is to condition the water to prevent any build up. Even the slighest build up on a coil, element or HX drives efficiency down.

hr