Mantle vs Double Coil Boiler: Elektromet & Kospel Comparison, Warranty, & Replacement Tips

Gentlemen, it's time to replace my grandfather from 73 (old galvanized).
Elektromets and Kospele both double-coil and mantle are available in stores nearby.
The mantle parameters crush the coil, but there are probably some disadvantages that as a regular user I do not know ??
which of the above enjoy a better reputation, Elektromet has a 5 or 6-year warranty and Kospel 3 (the condition is apparently the annual replacement of the magnesium electrode).
Maybe you recommend something else?

theoretically, two coils can be connected in series, because this is not a problem, and then you have a double heat exchange surface.
The question is what are the disadvantages of a mantle exchanger, because there are certainly some.

But with two coils, it occurs in the vertical version (with different variations - type Slim etc.), and double-jacketed in the horizontal versions (?) Only.
Maybe you are wrong description "double coil" which means only one coil pipe bent inside the boiler twice.

I didn't see them physically, but it's probably like that.
On paper, the mantle beats two coils per head, with heating power (27kW and 12kW makes a huge difference.
I wonder if such a coat will not cool the CO installation too quickly after the furnace fire (daily heat loss).
There remains the question of which products are more durable, my current galvanized boiler is from 1973, and I realize that the new enamelled one will not withstand half this, but I would be happy if I had 10-15 years of peace, I will add that I have water in the heating system (not glycol).

Maybe soon you won't have a choice, only mantles will remain on the market due to energy efficiency ...

I would prefer a coil, due to less cooling of the return water to the boiler.

Sstalone wrote:

Maybe soon you won't have a choice, only mantles will remain on the market due to energy efficiency ...

I would prefer a coil, due to less cooling of the return water to the boiler.

Nonsense. 2 and 3 vertical coils are and will be doing well. Especially that really big ones (400L and more) are usually vertical with a coil. And what does a colleague understand by energy efficiency? The nominal power of the exchanger is given with certain assumptions. Is your colleague absolutely sure that a typical installation reflects laboratory conditions? Because the power of radiators is given the same, e.g. 5kW ... assuming the flow of so much L / min and the temperature of the medium 95 ° C.

Incidentally, I have 2 Stalmet 200L coil as a supplement to the existing 120L Galmet double jacket. A heater warms up in Galmet in summer, and the heating is on a solar collector that usually pulls out 40 ° C on a sunny day, over 50 ° C on a hot day. So far, I've exchanged the anode 3x in galmet and 1x in stalmet (assuming replacement every 18msc). The durability of both would say similar, galmet is worse in disassembly because you need to unscrew many nuts and remove the heater with the anode.

Sstalone wrote:

I would prefer a coil, due to less cooling of the return water to the boiler.

This is also what I am afraid of, among others, which is why I wanted to hear the opinion of people who install, service or even use this type of equipment.

tronics wrote:

Nonsense.

I wrote about horizontal boilers. What energy efficiency is set out in the directive. You can read e.g. https://www.junkers.pl/files/JUNKERS_Dryrekaże_ErP_PL.pdf

Quote from page four: "From 2019 new energy classes will be in force. Then class A +++ will be added for heat sources, and at
domestic hot water preparation equipment class A +. The lowest classes G to E will be withdrawn in both product groups. "

Yes, I forgot to add that we are talking about horizontal boilers.

Sstalone wrote:

tronics wrote:

Nonsense.

I wrote about horizontal boilers. What energy efficiency is set out in the directive. You can read e.g. https://www.junkers.pl/files/JUNKERS_Dryrekaże_ErP_PL.pdf

Quote from page four: "From 2019 new energy classes will be in force. Then class A +++ will be added for heat sources, and at
domestic hot water preparation equipment class A +. The lowest classes G to E will be withdrawn in both product groups. "

In horizontal tanks, coils are usually called U, a double coil, it is a relatively weak solution and in this situation I also highly recommend a double-shell tank since colleague Alfred_92 explained that it is horizontal.

Why did I want my colleague to "develop energy efficiency"? Because the speed of heat transfer from one medium to another has nothing to do with energy efficiency (efficiency). At most, I would say that it is more about ensuring adequate thermal insulation of the reader, low daily losses (heat emissions from the tank to the environment), which is completely different to how the exchanger is built. Anyway, in the linked discussion of the directive it is also clearly indicated:

Quote:

Minimum requirements have been defined for indirectly heated hot water tanks. The basis of the calculation is in this case parking loss .

tronics wrote:

In horizontal tanks, coils are usually called U, a double coil, it is a relatively weak solution and in this situation I also highly recommend a double-shell tank since colleague Alfred_92 explained that it is horizontal.

Why did I want my colleague to "develop energy efficiency"? Because the speed of heat transfer from one medium to another has nothing to do with energy efficiency (efficiency). At most, I would say that it is more about ensuring adequate thermal insulation of the reader, low daily losses (heat emissions from the tank to the environment), which is completely different to how the exchanger is built. Anyway, in the linked discussion of the directive it is also clearly indicated:

Quote:

Minimum requirements have been defined for indirectly heated hot water tanks. The basis of the calculation is in this case parking loss .

In my opinion, why should I spend PLN 200 more on a double-shell tank compared to e.g. a U coil, since I do not need such coil power per unit of time? And what was the exchanger in the existing tank? Heated the hot water at a sufficient rate?
I don't know which boilers are more durable. If double-skinned were more durable, one could think about it. In addition, the diameter of the CO connection stubs can be important, the double-jacketed ones have a smaller diameter ... if someone changes the installation, this may be an option to think about.

I noticed that horizontal boilers no longer have four hot water connectors, but only two, because the parking losses are lower. In addition, if we have a forced circulation system, it matters how much the pump will have to run to exchange heat, then the double wall wins, as the boiler circuit protects the boiler return, the U coil wins, because we do not want to significantly reduce the boiler water and the pump and so it must walk, as the boiler is in gravity circulation, it does not matter, and the larger diameter of the connectors and pipes favors it.

As for the market, I heard that one of the producers will focus only on mantles, due to ErP, maybe it's just an excuse for customers.

Think about buying a used stainless steel boiler from brand manufacturers. On the Popular Auction Portal they are available in different variants and capacities, the fact of buying will probably be more expensive, just take into account that you will no longer need to replace it. I have a vertical with a double coil, with the possibility of installing a heater on GZ5 / 4 ". The 25 kW boiler outside the heating season with an incomplete wood bucket heats 160 l of water to a temperature of 55-60 ° C in 30-40 minutes. And the problem with anodes falls away keep the warranty and a matter of unavoidable replacement in the future.

Quote:

matter of inevitable exchange in the future

The anode is precisely to make this inevitable replacement avoided by regular replacement every 12-18 months depending on wear (in "acid" or oxygenated water it will undergo faster regardless of the number of microcracks in enamel and corrosion centers). In the case of titanium, replacement is several times less frequent. Stainless steel is a nice material, but let's not get paranoid. As a rule, the price difference will not pay back over its useful life.

andexp wrote:

Think about buying a used stainless steel boiler from brand manufacturers. On the Popular Auction Portal they are available in different variants and capacities, the fact of buying will probably be more expensive, just take into account that you will no longer need to replace it.

And here you can be surprised. Stainless steel also breaks from stress, alloy steel gets tired with age.

Returning to the topic: I recommend two-coat if it is to be horizontal + protection against cooling. In addition, the question arises: what heat source, which boiler, how many people use hot water?

25kW coal stove without feeder, one-story house, usually 4 people use CWO.
I care about good heat losses primarily because a morning shower in cold water (no oven with a feeder) is not pleasant.

Welcome. Buddy, a lot depends on whether you give the right amount of heat for the double walled boiler, because if it is not enough, I warm up after comfort. with this you won't have. a very good solution is to mount a vertical, hanging or standing boiler, on a separate pump with a check valve to make the central heating pump. it did not take heat from the boiler.