How do I adjust the hot water setting on a double boiler?

Setting the Boiler Temperature

When setting the temperature of both water and heating, it is important not to go to extremes. Do not use maximum or minimum values. A temperature of 38-39⁰ is good for hot water.

It makes no sense to set the temperature higher and then mix it with cold, as the boiler heats the full flow more efficiently than the half flow, which is then adjusted by the mixer.

If you use a thermostat, it’s best to install it in the coldest room, setting the temperature on it so that the house is comfortable.

It is important that it is not affected by close heating appliances and direct sunlight.

adjust, water, setting, boiler

This is a miracle that can come with the boiler.

Whoever said what, but the floor heating is the power. If you compare the heat transfer area of the radiator and the floor, the advantage is not in favor of the former. And the radiator cools down much faster than a block of concrete.

Having underfloored every room in my house except the bedrooms, I was pleased as a cat. And what a pleasure it is to walk into the bathroom in the morning and step on the warm as a rug tiles.

How to adjust the gas boiler: step by step instructions

Correctly set the gas boiler is not as difficult as it may seem at first glance. Our manual will help you master the principles of pressure, thrust, and power adjustment. And fix any problems that may arise along the way.

How to adjust the gas boiler?

Device of gas burner for the boiler

There are two types of burners, differing in device and in the way oxygen is supplied:

Atmospheric burner draws air from the room, which enters the combustion chamber. Fuel is fed to the nozzles located inside the element. The nozzles mix air and gas. And the final mixture comes out through the outlet holes. In the area of low pressure air is pumped all the time, which then mixes with fuel. The pilot burner always burns to keep the flame in the main element.

The fan burner consists of several parts (mixer, reducer, fan, motor, pressure switch, automated control unit). The fan blows the air which then enters the combustion chamber. The damper helps to set the necessary ratio of fuel and air.

Burner flame

The color of the flame is an indicator of whether the element is working properly. If it burns solid blue, all is well. The presence of other colors (especially red or yellow) indicates that the equipment is not working properly and that the entire boiler is not functioning properly.

Sometimes there is simply not enough oxygen in the final mixture. In addition, the problem may lie in the dust entering the equipment. Faults are also indicated by the fact that the burner works too noisily.

When the burner flame needs adjustment

Most problems are observed on atmospheric burners. They can be equipped with both floor and wall-mounted gas boiler. Causes of failures most often are:

  • Excessive element power. If a powerful burner is bought for a small appliance of average efficiency, problems cannot be avoided. The equipment doesn’t have enough air, so the flame turns yellow and the chimney gets clogged with soot.
  • The chimney itself is not well cleaned, leading to draft problems. Since the products of combustion are not fully exhausted and there is not enough air, the flame becomes yellow.
  • Defects or malfunctions of the burner itself make it impossible to adjust the gas combustion.
  • Pressure fluctuations in the gas system lead to the release of fuel into the chimney and its clogging.

Adjustment may be necessary after repairing the gas boiler and restarting, when changing fuel, as well as in the case if there is extraneous noise in the equipment. If it is necessary to replace the gas boiler, you will need a certain procedure.

Adjustment of the equipment

For the correct adjustment is used pressure gauge to adjust the gas boilers. Units equipped with a fan burner are automatically adjusted by the built-in unit. Appliances with an atmospheric burner are self-regulating:

  • Place a gas analyzer on the boiler;
  • Connect to the nozzle that conducts the gas;
  • Make sure that it is completely tight;
  • remove burner housing;
  • pressure gauge for the gas boiler measure the fuel pressure at the inlet;
  • Connect to the power grid, check the phases and jumpers;
  • Install the gas analyzer in the chimney and turn it on;
  • Measure the pressure level at the outlet, check the standards specified in the data sheet;
  • Correct the air flow with a damper.

What temperature to put in the heating boiler: low and high values

Let’s share our experience regarding different temperature modes.

  • 40 degrees. This mode is often uneconomical. At this temperature, the gas boiler may well underheat up to half a degree. Because of this the circulation pump and heating is not switched off. Accordingly, the gas consumption only increases. In some models of boilers, the flow rate may even be higher than at a set temperature of 70 ° C. In addition, such a temperature mode is better to give up in cases of unstable operation of the power grid. The coolant will cool down in a short time, the room will be cold in a few hours.
  • 50 degrees. Most tests show that at this temperature setting the gas consumption is the lowest. But the circulating pump runs long enough, which increases electricity costs. Plus, in the case of power outages, the batteries retain heat a little longer. In general calculations, such a mode of operation is less economical than the following.
  • 60 degrees. It is by right the most economical mode. It takes more gas than the 50 degrees mode, but the electricity costs are significantly reduced. The total cost is lower. And the room is heated better.
  • 70 degrees. This mode uses less electricity, but consumes more gas. But the more important problem is that with some models of boilers at this mode of operation the temperature jumps in the room are possible. They can be practically imperceptible, but also quite noticeable. The fact that the radiators keep warming up a room even after the shutdown heat in the boiler, then cool down, then again warm up strongly.

You should not set the temperature even higher, unless you live in cold northern regions. And there are several reasons. The main thing. you just do not need such high temperatures in the house. And even if you need to heat the room as much as possible, it is better to set the temperature lower. If the values are too high, there is an unpleasant smell of burnt dust from the batteries, polypropylene pipes wear out faster.

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So what the temperature should be on the heating boiler? We recommend about 60-65 degrees, if the temperature outside is not lower.10°С. If lower, you can increase the power. If it’s about zero outside, you won’t need more than 50-55 degrees.

What is the optimum temperature on the boiler for heating without temperature differences in the rooms?

Often the homeowner is not more important to save money, and uniform heating of all rooms in the house. The boiler runs constantly, not allowing the temperature to drop below the selected value. Of course, the electricity for such a mode will need more, but you can save on gas.

40 degrees for comfortable and even heating is not always enough. In this mode the house will be heated by an average of 20-20.5 degrees when the temperature outside is not lower.9°С. If twenty degrees in the room is not enough for you, you can set 45-50 degrees on the boiler.

Note! Many say that if the set temperature of the boiler is less than 70 degrees, it provokes the formation of condensation in the boiler, which is bad for the system. However, too high values can also damage the equipment over time. The same polypropylene pipes, which we have already talked about. So when deciding what temperature of hot water to set the boiler, be sure to find out what the manufacturer of a particular model says about this. Perhaps they have a clear norm.

Not heated DHW. the causes and troubleshooting.

The most common reason why D.H.W. does not warm up, is a strong buildup of limescale inside the heat exchanger. Scale not only narrows the water flow in the heat exchanger, it significantly reduces the water temperature.

The reason is the thermal conductivity of scale salts is many times less than the thermal conductivity of the metal of which the heat exchanger is made. Unit does not deliver hot water or hot water flows poorly if a piece of scale has broken off and blocked the flow of liquid.

Hot water does not flow into the faucet when the flow sensor does not work. It is a fan, which operates when water flows through it. The signal from it goes to the control board, it gives the command to heat the water. Sensor may be clogged and can be cleaned without disassembling it.

The sensor is a cylinder, located near the circulation pump. To clean, simply open and close the faucet in front of the unit. If this procedure did not work, you will have to dismantle, clean and put it back in its place. If the sensor is not working, you will have to replace it.

If the three-way valve is defective, the unit does not deliver hot water. The purpose of the three-way valve is to shut off the heating system when the hot water faucet is opened. When the valve does not switch, the boiler continues to heat water for heating.

The cause of valve failure can be elementary clogging, such as a piece of rust. If the problem is more serious, replace the valve with a new one. In addition, one of the simplest reasons why the faucet is not running hot water, can be a clogged gas hose or gas filter.

Three-way valve in sectional view

It will not be so unnoticeable on the heating, but the temperature of water from the faucet will be felt more significantly. Clean the hose and filters. Some of the above-mentioned points can also be the causes of problems with heating and hot water in wood-fired, electric and solid fuel (CT) boilers under the condition of similar design details.

Description of the two-contour gas boiler

To prepare hot water for household needs, each manufacturer of gas heating systems offers modifications with an additional circuit. When buying a hot water unit for your home, it will be useful to understand the scheme by which the work of a two-circuit gas boiler. This will help you choose it correctly for your needs and operating conditions.

The device of a two-circuit boiler Navien

Connecting the two-circuit gas boiler

Gas boiler in a private home is always installed in accordance with the project of the gas service, in a room that meets the requirements of regulations. Approach of gas is also strictly regulated and performed by gas technicians according to the rules. But, with the connection of the boiler to the heating network, and with the connection to the domestic hot water system, the owner can do anything.

How to connect a two-circuit boiler? At the first glance everything is very simple. On the underside of the wall mounted automatic gas-fired heat generator you can see.

  • Two 3/4 inch nipples to connect to the heating system (supply and return).
  • Socket 1/2 inch for gas connection (located in the middle).
  • Two 1/2″ connectors for hot water connection (cold water inlet and hot water outlet).

But you need to connect the boiler only according to the rules.

Example of two-circuit boiler connection layout. But other manufacturers may have a different configuration.

What is installed when connecting

  • On the outlet fittings of heating and hot water boiler you must install shutoff valves. They allow you to perform any work on the boiler without draining the entire system, disconnect the boiler from the system in case of breakdowns.
  • Gas connection to the wall mounted automatic boiler is usually performed by a flexible gas line that, through the valve ½ inch, is connected to the stationary gas line. But this connection, no matter how simple it looks, is performed only by gas service employees.
  • At the return of heating before the boiler you must install a coarse filter (the arrow on the body indicates the direction of fluid flow). The filter should only be installed horizontally, with the sump facing downwards. It is allowed to turn the sump a little to the side.
  • The same filter, only ½ inch, it is desirable to install and on the cold water supply in the DHW circuit. But in its place can be installed and more complex system of filters, which makes water of drinking quality.

Expansion tank

The heating system must have an expansion tank that stabilizes the pressure at approximately the same level (recommended to maintain it between 1.3 and 2.2 atm) during the coolant expansion when it is heated. Many gas boilers are equipped with expansion tanks in the volume of 6 14 liters, which is usually sufficient for modern heating systems, operating with a small volume of coolant.

But the boiler may not be. Then in the return is made on the tee branch, preferably close to the boiler (to the pump that is in the boiler to stabilize the pressure on it), to connect the expansion tank with a capacity of at least 1/10 of the volume of fluid in the system, and this is usually 6. 10 liters.

  • If the system is old with a large volume of water, which is typical for pipes and radiators designed for gravity, where the capacity may be up to 150. 200 liters, the regular tank in the boiler can be supplemented by mounted outside on the pipeline. They can operate in parallel, and their capacity for the calculation simply summed up, for example 10 liters in the boiler and 6 liters installed outside.

How the domestic water heating is activated

In all automated two-circuit boilers DHW heating is turned on automatically when it starts moving through the secondary boiler plate heat exchanger. This means that when you open the tap, the water will start moving, while the boiler will stop heating the heating medium (cut off its movement), and the energy will go through a plate heat exchanger to heat water for household needs.

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The movement of water through the boiler is due to water pressure in the plumbing or the impact of an external pump. The boiler itself does not supply water through the secondary circuit (plate heat exchanger).

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Thus, having connected the cold water supply under pressure to the boiler, at the output we get hot water, which we can immediately submit to the tap.

True, the cost of comfort in this case is so significant that many consumers either do not buy a simple two-circuit system initially, or subsequently supplement it, leaving behind a conventional single-circuit boiler and indirect water heater.

Disadvantages of hot water from a two-circuit boiler

The temperature of hot water is extremely unstable, you can always get burned. You have to wait until the hot water heats up and comes to the drain. The boiler always turns on when the faucet is opened, which causes increased wear and tear. There is not enough hot water, it is possible to take a bath for a normal time of 15 minutes only if the boiler capacity is at least 20 kW.

  • The scheme of DHW with a two-circuit boiler for comfort is much inferior to the supply from the boiler, when, when you open the faucet, there is an avalanche of hot water, a precisely defined temperature.

How to avoid the disadvantages of water supply with a two-circuit boiler

To avoid the critical disadvantages of hot water do the following.

  • Connect the indirect water heater with a remote mounted automatics to the first circuit, the second does not use.
  • Connect to the second loop boiler layer-by-layer heating (the best solution to the problem).
  • Connect to the second circuit an ordinary electric boiler (in this case the disadvantages are eliminated only half, the boiler is turned on every time the same, plus electricity is spent on maintaining temperature, but the option is half cheaper than switching to other types of boilers, so it is applied.)

DHW with two-circuit boiler

Circuit diagram for connecting a layer-by-layer hot water heater to a two circuit gas boiler. This boiler is equipped with an integrated pump for pumping water through a secondary heat exchanger of the boiler and the automatic on/off control.

  • In the boiler the water is in layers, hot water at the top, cold water at the bottom. As soon as the hot water layer decreases, the boiler pump switches on and pumps water through the boiler. Water heats up and remains as a layer at the top of the boiler, once the entire volume is heated, the pump shuts off.

Cold water is pumped from the water main downwards to the bottom of the boiler and hot water is taken at the top. In this way the water is always arranged in layers.

This equipment is comparable in terms of convenience and price with the configuration of “single boiler and boiler indirect heating. Therefore it is recommended for use.

Temperature regulation

To increase or decrease the temperature there are buttons “” and “-” on the right and left of the display (older models have a special regulator, turning clockwise increases the temperature and vice versa).

How to Increase Hot Water Temperature | Water Heater Adjustment

If a room thermostat is used, regulation is performed from the room thermostat and only the limit values are set on the boiler.

When setting the temperature, do not change the parameters in large increments. It is necessary to change the mode smoothly, give some time to overcome the inertia of the system. This will soften the transition to another mode and prolong the life of the boiler.

Then cold, then hot water comes out of the boiler, what to do

How to eliminate the clocking of the gas boiler in the DHW mode For heating and hot water apartments and small private homes with one bathroom are usually used dual-circuit gas boilers. The owners of such boilers are often faced with the fact that cold and hot water flows from the tap. As they say in the popular boiler taktuyut, DHW mode boiler periodically turns off, then on again.

Described in this article, the principles of adjustment, adjustment of the hot water system will work for two-circuit gas boilers of many brands and manufacturers, as well as gas water boilers.

Why is there cold and hot water coming out of the boiler?

Two-circuit gas boiler in the hot water mode (DHW) operates at a maximum capacity of. For example, the Protherm Gepard 23 MTV boiler manual states that with the factory settings of the maximum output of 23.3 kW., the boiler heats water to a temperature difference of dT = 30 oC, at a maximum flow of hot water of 11.1 l / min.

The design of modern mixers is made with the need to save water. For example, in a house connected to the central water supply, the following results of measuring the maximum flow of water: through the shower screen 6 l / min., sink horn 4 l/min., in the kitchen sink 5 l / min.

Normally, users do not open the water taps to the full flow to save water. In addition, to obtain a comfortable temperature, hot water is always mixed with cold water.

Boiler burner in DHW mode turns on at a water flow rate of 1.5 l / min. Turns off at 1.1 l/min. This hysteresis is a protection against periodic on/off operation of the burner when the flow rate fluctuates.

Taking these factors into account, the actual amount of water to be heated by the boiler in a minute will be approximately 1.1-4 l/min.

It is obvious that the difference between the factory setting of the maximum boiler output, designed to heat 11.1 liters per minute, and the output required to heat the actual flow at the water tap will be significant. The power of the boiler burner is regulated by the automation within certain limits. But the huge difference between the maximum power, and the power used to heat the actual flow of water, leads to the fact that the boiler automation is not able, without additional settings, to bring the boiler power to meet the needs of the DHW system.

Large excess of the factory set maximum capacity of the gas boiler in DHW mode over the power required to heat hot water in the water taps at users, leads to cycling (clockwise) heating of hot water. Boiler burner in DHW mode periodically turns on and off. Correspondingly, cold and hot water alternately comes out of the tap.

Setting, adjusting hot water temperature in hot water system

Diagram of tap water heating by a two-circuit gas boiler depending on temperature (T oC) and flow (Q l/min) of hot water. Working area. borders are shown with a bold line. Gray area, pos.1. Boiler cycle zone (switching between on and off)./OFF.).

For normal water heating boiler, the point of intersection of lines of temperature and hot water consumption (operating point) must always be within the operating area, the boundaries of which are shown in the diagram of the bold line.

If the mode of hot water consumption is selected so that the operating point will be in the gray zone, pos. 1 on the diagram, then the boiler will cycle.

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From the diagram shows that the boiler does not work in the gray area, to eliminate the clock at a low flow of water, the temperature of water heating is better to set the maximum, 60 oC.

As mentioned above, there is no need to prepare large streams of hot water in the house. It is much more important to ensure the comfortable use of hot water at a low flow rate. To this end, the work area on the diagram should be moved to the left. You can do this by reducing the maximum power of the boiler burner, reducing the gas supply by adjusting the gas valve.

How not to fight the clocking

Some “experts” advise to set the temperature of hot water lower, no more than 50 oC, in order not to dilute the water in the mixer during water intake, and to open the tap at full flow. Thus, it is suggested to get rid of beat, increasing the flow of heated water to the maximum. In many cases this really helps, because the water flow and temperature fall into the working area on the chart.

In systems with DHW dual boiler or with a gas water heater does not advise to do so, and here’s why. With this method it is necessary to consume water, and hence gas, much more than necessary. In addition, the need to always keep a large flow of water from the faucet, the inability to regulate the water temperature. all this creates a discomfort of using hot water.

In addition, the display of a two-circuit boiler does not show the temperature of hot water at the boiler outlet, but the temperature of the heating water at the outlet from the primary circuit of the DHW exchanger (return temperature from the DHW exchanger).

In systems with a two-circuit boiler automation keeps the temperature of heating water at the outlet of the primary circuit of DHW coil (return temperature from the DHW coil) constant, and the temperature of hot water at the outlet of the secondary circuit of DHW coil is not regulated.

The temperature of hot water at the boiler outlet will be as it will be, depending on the degree of opening of the water tap, the temperature of the water in the water supply system, the thickness of the scale layer. This means that every time you open the water tap the temperature of hot water will be different.

Therefore, the required temperature of hot water at the boiler outlet can not be set in advance on the display. If you set on the display the temperature of the heating water, for example 50 oC. the temperature of hot water from the faucet will always be less, and less each time is different.

In the DHW system with a two-circuit boiler the water temperature is more convenient to regulate directly at the tap at the time of discharge, mixing in the mixer with cold water. To have such a possibility, you need to have some reserve of water temperature at the boiler outlet.

For the comfortable use of hot water from a two-circuit boiler must be set and set the display in the DHW mode to the maximum temperature of 60 oC.

Setting the maximum power of the boiler burner in DHW mode

In order to ensure that the boiler in DHW heated water evenly, not taut, even at minimal water flow rate, you need to make the maximum output of the burner less, reducing the gas supply by adjusting the gas valve. The whole operating range in the diagram will move to the left.

As a result of the gas valve adjustment, there will be no signs of burner malfunction in DHW operation, when the flow rate of hot water is varied over the whole range, from the maximum (6 l/min) to the minimum, specified in the manual (1,1 l/min). The temperature of hot water can be adjusted with the mixer, changing the flow of water and mixing it with cold water within a limited, but quite comfortable limits.

Setting, adjusting the SIT gas valve

SIT gas valve. 1. test connection for gas pressure at valve outlet, in front of burner; 2. test nut for maximum gas flow rate; 3. test screw for minimum gas flow rate; 4. adjustment device cover; 5. test connection for gas pressure at valve inlet, in gas network.

How to set hot water boiler pressure

Manufacturers of two-circuit gas boilers of many brands install a gas valve Italian company SIT on the boilers. Adjust the maximum and minimum boiler burner output by turning the adjustment screws located on the valve body.

Adjust the gas pressure upstream of the burner in DHW mode:

  • On the boiler display the hot water temperature must be set to 60 oC. (For setting the DHW temperature, see above).
  • Remove the cover of the regulator (pos.4 on the picture).
  • Turn on the boiler in domestic hot water mode, opening the hot water tap at maximum flow.
  • Set (decrease) the gas pressure in front of the burner by means of the maximum gas flow regulation screw (pos.2). Turning to the right increases the gas supply, while turning to the left decreases it. Visually inspect the height of the flame in the boiler burner. The purpose of the regulation is to decrease the gas supply to the burner so as to ensure that the burner operates continuously and the temperature of hot water from the tap remains constant and comfortable.

Control the gas pressure in the network

The gas pressure in the gas network can drop below the permissible pressure for the operation of the boiler. It is necessary to monitor the pressure periodically, especially in frosty weather when the gas consumption in the network is at its highest.

Static pressure and dynamic pressure are measured at the boiler inlet. Static pressure is when the boiler does not use gas. Dynamic pressure is measured at the maximum gas flow rate of the boiler.

The pressure in the gas network, at the gas valve inlet, shall be measured by connecting the pos.5 tube of U-manometer. To measure the dynamic pressure open the hot water tap to the full flow.

The normal dynamic gas pressure at the gas valve inlet must be within 1,3. 2,5 kPa (13. 25 mbar or 132. 255 mm). water. st.). If the dynamic pressure deviates from this range during measurement, contact the gas service

See how to measure the gas pressure at the inlet and regulate the minimum and maximum gas pressure at the outlet of the SIT gas valve in this video.

You can eliminate tap water by reducing the maximum pressure. To do this turn counterclockwise the adjusting nut.

U. shaped manometer

It is possible to tighten the pipe of 8 mm inner diameter on the gas valve fitting. For a pipe with a different diameter will have to pick up an adapter.

After completing the measurement, remember to carefully tighten the locking screw on the measuring connection and check its tightness.

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