A modern gas stove and an old installation with cast iron radiators.

Question

I see many professional practitioners here, so I will shyly ask about the following issue - parents are already old and heating based on a coal stove, which may be problematic in the long term. Does the installation of a modern gas stove with an old installation with cast iron radiators and...

W0jtek92 · Accepted Answer

If gas, then only condensing. In fact, large cross-sections of pipes result in heat losses. But it's not that bad. Is the current system gravitational?

W0jtek92 · Accepted Answer

So I'm shooting that your radiators are about 10 kW. If you are going to replace these valves, then on average one thermostatic valve + head will cost about PLN 120. The price of a wireless programmer is about PLN 300-400 and as for the boiler, you need to check what service availability in your area and what installers who will make these installations will offer. There are really many brands and there is a large selection of boilers on the market. So you have to look around a bit.

piotr_boncza · Accepted Answer

It makes sense, and it is as serious as it has already been written. And it is right that only condensate, and necessarily with the weather. My only disagreement is that thick pipes are loss-making The heat given off by the pipes stays in the house, so if the pipes do not lead through uninsulated rooms, the losses are negligible. Now insulating pipes is easy. Properly set weather control will minimize the effects of greater inertia of the installation, and the elimination of the air supply to the boiler will reduce losses in the boiler room. It is then useful to insulate the boiler room. Especially doors and windows, because it is generally not paid attention to there. I have one, and I find that the operating costs are not much lower than that of a gas condensing boiler. The efficiency of this scrap may have been high, but only with a perfect coal and a new boiler. And nobody saw the perfect one. I have good combustion, provided that I clean the boiler every few days, the coal is good, dry and I carefully select the parameters, depending on external conditions, especially humidity. The gas condensate takes care of it for me. The average user is not aware of this and loses fuel without any sense. He does not see the need for frequent cleaning of the boiler and careful adjustment. The gas boiler you showed is an archaic gas combustion device. Which also heats the house a little. Hope no one will buy it. It's just that, according to the rules in force here, you cannot provide expiring links. Better to put a photo of the object: If possible, connect the water heating to the boiler as well. It is best to install a boiler heated by a boiler. The thirteen-year-old terma will end soon and the tray is much more economical and convenient. If you want to reduce costs, you do not have to modify the installation and replace the valves. The weather-room regulates the temperature well.

piotr_boncza · Accepted Answer

They order, but they already have money saved for a year of cheaper heating We are constantly discussing what first and what can be left for later, reducing initial expenses. If you spend that money on thermostats instead of the weather, the financial effect will be much smaller.

ogi4 · Accepted Answer

The condensate in this type of installation achieves the highest efficiency.

dplus · Answer

there is now a pump at the furnace that is activated by the temperature at the exit of the furnace

W0jtek92 · Answer

Approx. And an additional question is whether there are supply valves at the radiators? If not, you have to insert them. If they are, I would recommend replacing them with thermostatic valves with heads for gas heating. And now the most important thing. How much money do you want to spend on these installations?

dplus · Answer

There are valves, but not thermostatic. The cost of the furnace + the necessary changes that will pay off in a short time. I secretly hope that these slates will be exploited here

W0jtek92 · Answer

Well then. It would be good to close the system that is open (depending on the height of the water column). To make a pressurized installation, the installation will be large, so an additional safety group will be needed. Replace radiator valves with thermostats. How many of these radiators? And how big are they? For all this, a good room programmer, preferably a portable one. And the external sensor for the boiler, because both it and the programmer will save a lot .. And just out of curiosity what brand was the old gas stove? Was it maybe jubam?

dplus · Answer

The radiators are large, there are about 10 ribs in each room and there are 8 of them.
The gas stove was custom-made by the company on the basis of a stove of an unknown brand. I looked around on the Allegro and our stove is almost identical to the one in the attachment, only the front installation is more elegant and lower, but the regulation scheme is probably identical. I can see it has depreciated a bit

dplus · Answer

Thanks. You gave me a spark of hope that there would be no revolution in the installation.

Zbigniew Rusek · Answer

Thermostatic valves are needed because the weather-conditioning will not prevent the rooms from overheating. External sensors are given on northern walls (stupid regulations) and windows are usually facing in a direction other than the north. As a result, the weather sensor receives a signal that it is cold and needs to be heated (it is in the body shade), while the sun is shining and heating the rooms strongly. As a result - despite the floor tiles - Saudi Arabia is in the house (it is even more noticeable when you live in a block of flats, on a high floor). How do you understand these thick pipes? Are e.g. the diameter of the twigs 3/4 inch or even more (e.g. 1 inch)? Sometimes you can find such thick twigs - for gravity, you could use 3/4 as standard, when the radiator is very large (e.g. 25 ribs), even 1-inch. Gravity heating requires this due to the low circulation of the heating medium (and also requires larger heaters than with the pump, i.e. they are probably slightly oversized). By the way, there are 10 ribs of the T-1 heater, which is more than 1kW - for the parameters of 90 degrees it is 1250W (or even 1300W). Only that such parameters are not available for radiators in practice (it is even dangerous - burns).

dplus · Answer

Thanks for your attention, I have already added a photo of the stove as an attachment. Thick pipes compared to those currently used. The installation is rather typical for the time and all pipes are probably 3/4 inch.

rogera · Answer

The issue of the weather regulator operation is not so simple, if the parameters are set correctly, there is no overheating of the rooms. The influence on the boiler operation with this type of regulation is:
1.Heating curve - its slope / steepness is determined by the minimum outdoor temperature (lowest expected outdoor temperature in the region) and the design temperature (design supply temperature to be achieved at the minimum outdoor temperature)
2. A parallel shift of the heating curve up or down is obtained by adjusting the T parameters of the room and / or the set room temperature. Correction setting is appropriate when measured
room temperature deviates from the set desired temperature with a thermometer.
Regulation mode - The user selects whether the heating curve will be influenced only by the outdoor temperature or if it is determined by a mixed influence of the outdoor temperature and room temperature parameters.
4. Type of building - Due to its ability to accumulate heat and its characteristic resistance to heat transfer, the building delays the effects of fluctuating outside temperature on the interior. Therefore, the heat demand in the rooms is not determined by the temporary outside temperature, but the so-called attenuated outside temperature, thanks to which the regulation can be adapted to the characteristics of the building. run time. The time constant is derived from the formula: factor x run time = time constant of temperature suppression in hours.
In the case of a condensing boiler, thanks to the parameters as above, we obtain continuous operation of the boiler with a momentary power adjusted to a given building without shutting down the burner and, as a result, with maximum efficiency.

piotr_boncza · Answer

I don't know about the others but in Junkersowy FW, I install the weather in a model room and in this case I set 40-60% of the room temperature influence. I did not write that room thermostats are unnecessary. You are right, they are badly needed, but I have considered a situation where limited resources do not allow me to do my best. Then we get a greater effect by installing weather control for ~ PLN 750 than thermostatic valves on all radiators. I did a lot of such modifications and sometimes you have to flex a bit to add these valves by adjusting the diameters and lengths so that it looks decent.

rogera · Answer

On old installations, it is necessary to install thermostatic valves (preferably with pre-flange). These valves make it possible to equalize the flows through radiators of different capacity / power (size in relation to the volume of rooms) and allow setting lower temperatures in the rooms that we do not use. the next year, after replacing the boiler, investors order thermostats to be installed due to overheating of some of the rooms while at the same time under-heating other rooms.

bobi70 · Answer

I dare to raise the topic. Did a colleague of the author decide on the proposed solution, i.e. condensate plus an old cast iron installation? If so, it's nice to get feedback on how it works.

koloq · Answer

Then maybe I will add from myself,
I am after such modernization, a terraced house inside, windows replaced with 3 panes, insulated, house area 240m, usable 130, the rest basement, garage unheated boiler room - there is always around 10 degrees, at -15 outside it drops to around 5.
I threw away the old gas stove - similar to the friend who started the plot. I put in the condensate of the junkers smart zsb22 + 120l tank + weather station, I replaced the radiator valves a year earlier with a thermostatic one with sealing - but here everything is open to the maximum
The whole installation is old - cast iron radiators, thick pipes
In addition, I have a wood, coal, etc. stove - everything works in an open / gravity system, I also put on a garbage pump.
The condensate also works in an open system - the pressure required is ok, the water column is about 11 meters, my neighbors have the same and it works for over 5l years on the vailant without problems
at home I have a mouth temperature of 21 degrees, saving for 19.5
the only problem I noticed was the problem with heating the rooms on cast iron radiators - heating Monday-Friday I have set from 16-23 and in the morning 5-8, which is when we are at home, despite the frost, cast iron gas heaters need a lot of time to heat the room - at about -5 to 0 outside the temperature of 21 in the living room, where it is reached maybe after 4 hours, which I consider unacceptable - according to the programmer, the stove gives a supply temperature of 60-65 degrees, but cast iron needs much more if you want to reach the temperature quickly. For information, I will say that the living room has about 30m2 and the radiator has 25 ribs, 60cm high, which gives about 3250W, but at a design temperature of 75 or maybe higher. I wonder if I should not replace the radiators with plate ones (leave the old pipes), (especially since in the bedroom above it is even more difficult to get the right temperature)
e.g. purmo C33, which have high efficiency, heat up quickly and do not need such a high supply temperature - I thought about oversizing them, of course - prices are not high, so the exchange can close to PLN 2500 - all of them,
I wanted to ask if anyone has similar experiences?
When replacing radiators, my goal would not be to reduce bills, but to increase thermal comfort
greetings

wnoto · Answer

If the house is insulated (wall accumulation works), then a better solution for you will be lowering the temperature on the stove, but constant heating. Perhaps it will also help to obtain more condensate - that is, less gas consumption. (Especially on less frosty days)

rogera · Answer

I have a few questions:
1. Does the weather regulator of the gas boiler measure the temperature in a representative room of the building?
2. If it measures the room temperature, is the thermostatic head at the proverbial "max" open in the place where this measuring element is installed?
In fact, cast iron radiators take a long time to heat up, but when they reach the required temperature, after turning off the boiler, they will still give off heat for this period. I suggest you reprogram the working time, e.g. from 1 p.m. to 8 p.m. and 2 a.m. to 5 a.m. and look at the behavior of the installation (room temperature)

bobi70 · Answer

Do one important thing. Measure the temperature to which your indoor temperature drops realistically.

It was me who raised the topic.
I am very interested in these issues from the practical side. I want to do something similar.
My difference is that the gas will be connected to the CO through the exchanger. I want to be able to smoke in parallel.
The primary source will be garbage to which I have an oat-tanning attachment attached. When for some reason the garbage stops, the gas would be triggered.
But the gas one will then have the initial temperature on the radiators. So either it will start from the heated ones or it will only top up.

Why am I asking for the indoor temperature.
Well, at home, I wanted to release this oatmeal at the cast iron radiators in a thermostatic cycle.
I set the 22st on the driver. with hysteresis of 2. Everything was seemingly OK. However, it turned out that with warmed up rooms, after reaching 22 the time after which the temperature drops to 20 (hysteresis 2) is about 3 hours! At that time, the flame on the burner was extinguished. The worst part was at night, when the temperature of 22 degrees Celsius is a bit inconvenient for sleeping.
I used a simple trick. During the night, I turned on the burner power supply interruptions by controlling the external clock. 1.5 hours of work and 1 hour of break. in this way, the temperature on the radiators lowers a bit and cools the rooms, but not so much as to lose thermal comfort.
I am afraid that by controlling the room temperature at the level of 19 degrees Celsius, you achieve complete cooling of the water in CO. As a result, it is necessary to warm it up. And it's not that simple when it comes to time!

koloq · Answer

Hello Answering the questions 1.- the regulator is in the living room, which is a representative point, the living room is open to the hall, which is also heated - downstairs, apart from the bathroom and from the porch, I do not have any doors 2. the heads at the bottom are always open to the max - this is the hall, kitchen, living room Will try regulation after advice. Thank you for the fast reponse Added after 23 [minutes]: Hello. In general, the temperature on very frosty days (-10 during the day) dropped to 19 degrees during the day in the living room (in the bedroom above / similar area as the living room to 16.5) In my case, 2 stoves were also tied together, but now, after installing a new stove, it is not like that / at least it does not work like that (I am not a specialist in terms of installations, I was learning a bit on a living organism now) Generally, I had one situation when it was horny in the garbage, and after some time when I was bathing my baby, I noticed that the heater wasit gets cold in the bathroom, I went down to the boiler room and it turned out that the junkers turned on the pump (although the heating with the gas stove was turned off) because the temperature outside fell below 3 degrees which gave him a signal to turn it on (in junkers it is the frost limit temperature which later I changed to -5 degrees, it can't be lower, the programmer does not allow) but by continuing the junkers pump blocked the outflow of water from the garbage - I got a little scared, turned off the gas stove from the mains and ... the water started from the garbage - I thought it would tear the pipes boiled a little and made noise in the house from the working pipes. So something is wrong with my connection, I guess you will have to install some valves, but I have to arrange it with the plumber who did it / or for the safety of the new one. Returning to the topic, when it comes to cooling the water, it actually cools down, but heating it to 55-60 degrees takes relatively quickly, as far as I know, the controller also makes sure that the water temperature, even in the saving mode, does not drop below a certain value. That is why I have doubts whether the cast iron radiators I have are not too small for the new condensate I also considered adding ribs e.g. in the living room I have 25 and I have the option to add 7 - there is enough space, I have ribs because I once dismantled the radiator during the renovation of the apartment and this is how I stayed in the garage - just the same spacing the same applies to a bedroom where there are only 20 ribs and it is definitely harder to heat this room - unless it heats garbage to 80 degrees - not profitable with gas Generally, my goal is to switch to gas only and preferably reach a temperature of 22 degrees, night 19-20 greetings

bobi70 · Answer

I am also not a professional plumber. And I do not know the practicalities of this type of installations. However, theoretical knowledge tells me that combining 2 sources into one system should not be done directly. Assuming parallel operation of 2 heat sources supplied in different ways, even with forced circulation, one should be plugged in through the exchanger. Not so long ago, I also discussed this in another forum. The guys proved that they have gas boilers connected to the CO system without any exchangers and it is ok. But when one of them wrote that he had a gas boiler installed in the boiler room with a coal boiler, even plugged into the same chimney shaft, I understood that I talk to boiler makers with a high level of amateurism. You just don't do it, because no security regulation allows it. Back to the topic. If in the garbage, the installation was correct and you had no problem with heating the rooms, in my opinion the problem lies in the controllability of the boiler. The inertia of this system is large. In my opinion, you should lead to the same situation as I have with oats right now. In short, in full machine it won't go. Or you have to look for an advanced method. I have practically continuous heating of oats. I only control the water temperature on the system. It is enough and it is OK. The primitiveness of my controller does not allow to change the temperature of the boiler water depending on the time of day. There is only the set temperature and the end. The boiler works, reaches the set value and if it has it, the burner is stopped. In this way, during the day, at a boiler temperature of 45-50 in winter (!), It has warmth in the house. I do not cool the installation as it is with extinguishing rubbish. For me, however, it was too warm at night. I have put the burner off temporarily. This has its drawbacks, but the problem of nighttime temperature drop has been resolved. If the condensate controller allows it, in my opinion you should give up full weather. You should give up the control of the room for a test and only switch to controlling the water temperature in the system. And here, if necessary, introduce the task - lowering the temperature at certain times of the day. I do not know what the controller allows, but in your case it should be done in such a way that the boiler water temperature is set depending on the outside temperature. Possible reduction of the system temperature by 10 degrees during the night (on trial). But not lowering the room temperature! Moving the room temperature by 2-3 degrees is a lot, as long as it has been cooled for a long period of time. Heat the room by 2-3 degrees. It is not the same as warming the air in this room by 2-3 degrees. You should check how the advice of one of your colleagues is working - other heating time frames. Start earlier and end earlier. This hour or one and a half stop with functioning household members should not matter. But that will only show a practical approach. Not a theory. I don't know what the layout of the house is. Do you not have, as with me, that the rooms on the first floor (if any) are slightly cooler? For me, it is the fault of insulation and installation on the first floor converted into thinner pipes. I have the ground floor connected with 3/4 and the floor with 1/2. Here the physics bows and here you have your answer why the stove once acted to you as it did. Water, despite being forced, will always flow where it has less resistance. Also, if you have a cooler one upstairs, you should cross the ground floor a little. Posing more resistance to the water. But here also what I did bows down and I will try to get away from it. I do not know if this is true, however, without an empirical approach it will not be established. Similarly, thermostatic valves are valves with a reduced flow compared to traditional ones. Even though they are fully opened, the flow may be throttled. After changing my valves to such, I get the impression that it is true. The radiators are cooler than when traditional mushroom valves are used. You can also cover them on them by screwing the knob. Valves with thermostatic heads are good, but the conditions must be correct for their use. Exposed heads, no objects may obstruct the air circulation. Radio heads work quite nicely, where there are only actuators on the radiators and the controller in a representative place. Solutions such as found in Polish homes, where the thermostatic head is covered by a window curtain, or a sofa pillow or a wardrobe, disqualify their proper operation. Also. I would check how the pump behaves. A gas boiler is a boiler with a relatively low internal flow. Water flows slowly through the boiler to warm it up quickly and strongly. Is it not so that the water, as you write, heats up quite quickly, but it is the fault that the pump is running slowly. It heats up quickly, but it is apparent heating. Because when the pump chases her away, she's cold again. I would try to run the pump to the maximum and gradually lower the speed of work. Fast flow through the boiler = slower heating of water and radiators, but more even and stable.

koloq · Answer

welcome back
I played around with the settings a bit and now the settings are as below:
Monday - Friday 5: 00-12: 00 heating 21.5 and 16-22: 30; saving for 19.5 the rest of the time
Saturday-Sunday - heating from 8:00 to 23:30 at 21.5, night saving at 19.5
thermal comfort much better, the house heats up quickly to the set temperature, only a bit cooler in the bedroom 19 but ok for sleeping, I'll think about adding these ribs in the summer
I was most surprised with the low bill for January PLN 340 (160m3), it was the first month when I only smoked with gas and at such costs you do not want to smoke in garbage

Zbigniew Rusek · Answer

I would not be in favor of adding ribs, because 20 ribs for a 16-meter room is really a lot. 10 ribs heat a 19-meter room, even with 3/8 '' twigs. These interruptions in heating probably caused difficulties with reheating.

KarolW · Answer

Hello everyone
to Koloq: you can enter your heating costs.
I have a similar situation and size at home. I have partly old type cast iron radiators and partly aluminum finned radiators - open system. I want to replace the smoke with condensate and I'm curious how it will work.

An interesting thing, I read that there is a feed / return temperature of 60/50 degrees in coal carriers. For me, most of the season, the exit is about 38 degrees. When there were severe frosts, maybe 42/43 degrees. in rooms about 21/22 degrees without thermostats. (I know how it affects the boiler and the chimney ... but there was no way out) I mean the matter of temperature and efficiency of the radiators, which are properly selected for the room at a temperature probably much higher.

In fact, maybe one of my colleagues will say whether the condensate in the open circuit will be a good solution here ... or maybe some other option.

And one more thing: what do you think about Immergas stoves and what does the cooperation of these stoves with a solar installation mean?

greetings
Charles

jacek1296 · Answer

I will dig out the topic: I live in a block from the late 70/80, 12mx12m, insulated, plastic windows. Unheated basement, ground floor, first floor, insulated attic. A 25kw 20-year-old garbage boiler, so it's probably worth a preventive replacement, although it works surprisingly well, with a circulation pump, cast iron radiators, a few listed on alu, but the pipes remain unchanged. Open system with a stove in the basement, an overflow vessel on the first floor, under the ceiling. Hot water from an electric boiler.
Plans: gas combi boiler, the problem is the basement recessed into the ground to about 0.7 m and its height of about 1.8-1.85 m. For this hot water reservoir. Can he solve it somehow, not spend millions?
?

ogi4 · Answer

The condensing boiler likes a large amount of water in the system, i.e. old heating. Pipes in places where we do not want to heat need to be insulated so as not to incur additional costs when heating with pipes. You can leave the system open by securing the boiler with a pressure sensor on the system. So it is enough to replace the boiler and modernize the chimney. The rest of the information 506 035 666

Wojewoda82 · Answer

ad 1) A boiler with a high minimum power likes a large amount of water. But a big deal to hesitate, sometimes too hot (when the boiler turns you off and the radiators are still hot), and sometimes too cold (before the radiators get warm). Boilers with a low minimum power, like most condensing ones, have a relatively low power and without any problems on radiators with a small volume with appropriate radiators it provides better comfort. ad 2) Pipes inside the apartment do not need to be insulated, always up to several hundred W of heating power more supporting the radiators, which allows to slightly lower the CO temperature (bare pipes inside the apartment do not cause heat loss). Pipes walled up inside external walls can be insulated, because here you actually lose a bit. ad 3) some 95% of the current new boilers require a closed system, many of them will not even start up when the pressure will be in the order of 0.3-0.7 bar in the central heating system (open system with the vessel 1-2 floors higher). So to sum up, you write nonsense. Take an interest in floor standing condensing boilers, the so-called modernization, for old installations. They have exchangers resistant to muck with CO, although it is worth flushing the installation as a preventive measure. Some of these boilers can also operate on an open installation.

A modern gas stove and an old installation with cast iron radiators.

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