Mixing unit for floor heating: function device accessories

Greetings, comrades! Today we will find out what the pumping and mixing unit for floor heating, which fitting it includes and how it works. In addition, we learn what other equipment necessary for the operation of low-temperature underfloor hot water heating system. So, in a way.

Schematic diagram of the collecting enclosure with a mixing unit.

What it is

Termosmesitelny node for underfloor heating allows to establish an independent circuit with a water temperature, lower than in the main heating circuit. For this purpose, the recycling water or antifreeze: chases coolant circulating pump for a low-temperature loop until the until cooled to the critical temperature, and then mixed into the hotter portion therein liquid.

Pumping and mixing unit by Valtec indicating coolant flow direction.

Areas of use

When is it necessary?

• When connected to a water underfloor central heating system,. The water temperature therein most of the heating period is significantly higher maximum allowable for underfloor heating to 40-45 degrees, and in the cold peak altogether is raised to 90-95 ° C;

Wiring diagram of floor heating to district heating.

Note that the effect of floor heating on the temperature of the neighboring cells is minimized. The case in a small volume of spent coolant returning to the riser: the basic amount sent for recycling.

• When using the boiler is unable to work with the cooler return line 55-60 degrees. In this category, in particular, includes all solid and traditional gas boilers: when cooling exchanger below +55 ° C it begin to condense combustion products containing hazardous metal acid;

Condensing gas boilers - a pleasant exception: they are designed to work with a coolant having a temperature of 30 degrees.

• If there are at least two heating circuits of different temperature. Typically, this is actually a warm floor and convection heating radiators or other wall-mounted radiators.

Combined heating system with radiators and underfloor heating.

without mixer

When mixing units for underfloor heating is not needed?

Under two conditions:

1. coolant temperature is the same in all circuits;

In this case, heating devices in the circuits may be different. Radiators and convectors work well with typical water floor heating temperature of about 40 ° C. Relatively low heat compensated for large size devices.

1. The heat source can provide a suitable coolant outlet temperature. Apart from gas condensing boilers are capable of all kinds of electric boilers and heat pumps.

Tying heat pump operation providing underfloor heating. Node mix with offline, the circulation pump supplies coolant directly to the heating collectors.

There is another loophole that allows to save on the purchase of the mixing unit - the use of the return radiator heating as feed for underfloor heating. However, the solution has a number of drawbacks:

• The impossibility of an independent trip one of the circuits;
• Adjust the temperature of each loop independently of one another can not be the same;
• Tank line at the entrance to the boiler It will have a temperature of 25-35 degrees, which is too much for all solid and classic gas units.

Device

Required elements

The mixing of warm floor includes:

Picture	Description
	Circulation pumpProviding movement of the coolant in the low temperature circuit.
	Thermostatic three-way valveResponsible for supplying the hotter coolant as small cooling circuit. The valve may be a bellows (i.e., using the expansion of solid, liquid or gaseous medium while heating) and electric (equipped with a thermocouple and actuator). Optionally, the device is equipped with a remote temperature sensor - capillary or electric.

How it works?

1. When the temperature corresponds to the predetermined small loop, the pump provides a constant volume continuous circulation of coolant therein;
2. When the temperature drops thermostatic valve is slightly opened, and the cooled portion of the circuit is mixed with hot water or antifreeze;
3. Once the temperature reaches a predetermined valve closes again.

In practice, any thermostatic valve - self-regulating system, and after a short time he It finds the position at which the temperature of the coolant in the loop of floor heating is kept constant level. Valve position changes only when the heat the room or the coolant temperature at the outlet of the boiler.

Work three-way mixing valve assembly.

Often mixer equipped with no three-way and two-way valve (thermal head). In this case, the bypass between the flow and return to the pump installed on it is connected immediately after the thermal head.

Mixer with two-way valve.

optional elements

In addition, the mixing unit circuit may include additional equipment:

Picture	Description
	Collector - comb flow and return. Because of the limitations associated with the hydraulic resistance of the pipeline, the length of one loop can not be more than 120 meters, a large space is required to mount more loops.
	Chokes or thermal head for separate adjustment of throughput capacity circuits (read - their temperature) and ball valves for their independent shutdown.
	automatic air for the supply and return manifolds, precluding their airing and disruption of circulation.
	Sbrosniki, allow to drain both collectors.

Please note that the content of the collector cabinet sbrosniki above are laid in mortar or a clean floor heating surface. Reset circuits completely impossible, so if you can stop heating in the winter, for any reason, as a coolant have to use antifreeze.

In addition to the mixer

What a fitting, in addition to the mixing unit need when installing floor heating with his own hands?

Here is the list of required for the heating elements:

• Expansion tank. It is divided into two compartments (air and intended for coolant) container and is designed to compensate thermal expansion of the coolant. The liquid is almost incompressible, so when heated in a closed volume pressure increases very quickly. The air in the air chamber of the expansion tank becomes a buffer repeatedly pressure retarding growth;

In the photo - the expansion tank in the low-temperature heating system.

To choose the correct volume of the expansion tank will help the simple instruction: it must be equal to a tenth of the volume of coolant. That, in turn, is equal to 15 liters per kilowatt power boiler.

• Safety valve, Dropping an excess of coolant with a dangerous pressure increase. The battery heating system it is usually set at 3 kgf / cm2;

Apparatus safety valve.

• manometerThat allows you to visually monitor the system pressure;

The manometer and a safety valve placed at the outlet of the boiler or other heat source - where the pressure begins to grow most rapidly when stopping circulation.

• Air vent. Usually it is installed next to a manometer and a safety valve (combined into one node devices called boiler safety group). However, if automatic air vents are included in the packaging of the collector group, put the additional air vent is not required.

Including automatic air vent security group Compact TIM domestic production. Price - 700 rubles.

conclusion

I hope that I was able to answer all reader questions. Learn more about how mounted mixing unit for floor heating, you will help the video attached to the article. Waiting for your additions to it. Good luck, comrades!