Collector with flow meters for underfloor heating


Today, many home­own­ers pre­fer res­i­den­tial heat­ing sys­tems, in which the lead­ing place is giv­en to warm water floors. Using the ther­mal ener­gy of a liq­uid heat car­ri­er, it is pos­si­ble to achieve high qual­i­ty indi­ca­tors in home heat­ing. The very design of the heat­ing sys­tem, at first glance, gives every rea­son to con­sid­er this method of heat­ing effec­tive. The prin­ci­ple of oper­a­tion of water floors is fun­da­men­tal­ly dif­fer­ent from tra­di­tion­al heat­ing meth­ods. In this sit­u­a­tion, the func­tion­al­i­ty of each ele­ment, device and device includ­ed in a sin­gle set of equip­ment is impor­tant.

Mix­ing unit of under­floor heat­ing sys­tem with flow meters and ther­mostats

The high-qual­i­ty oper­a­tion of the heat­ing sys­tem large­ly depends on how com­pe­tent­ly the coolant is con­sumed in pipelines of water floors. Under­floor heat­ing col­lec­tors cope with this task, which, togeth­er with flow meters, ensure the ratio­nal dis­tri­b­u­tion of boil­er water to the heat­ing cir­cuits. What is the tech­no­log­i­cal con­nec­tion “col­lec­tor — flow meter”, how impor­tant are its func­tions, and how does it work? We will try to get acquaint­ed in more detail with these and many oth­er ques­tions.

Underfloor heating and the space occupied by a collector with flow meters

A fea­ture of a warm floor as a heat­ing sys­tem is that the heat­ed coolant, mov­ing along the heat­ing cir­cuit, trans­fers part of the ther­mal ener­gy to the floor sur­face. Thus, due to floor heat­ing, heat is trans­ferred to the air mass cir­cu­lat­ing inside the room in the direc­tion from bot­tom to top. A num­ber of devices are involved in the sup­ply of warm water to the heat­ing cir­cuits, the inten­si­ty and flow rate, includ­ing:

Con­trol over the dis­tri­b­u­tion of the coolant is car­ried out by a flow meter for under­floor heat­ing. This device plays one of the key roles in the oper­a­tion of the entire pump­ing and mix­ing group. Under­floor heat­ing col­lec­tors are designed to sup­ply hot water and col­lect waste heat car­ri­er for its fur­ther use in the pipeline of the heat­ing sys­tem. In the pump­ing and mix­ing unit, the hot water com­ing from the heat­ing source is mixed with the coolant returned to the cir­cuit — the return flow. The func­tion­al­i­ty and effi­cien­cy of heat­ing floors are based on this prin­ci­ple of oper­a­tion.

Mix­ing unit with rotame­ters of the under­floor heat­ing sys­tem

Togeth­er with the oper­a­tion of safe­ty valves, rotame­ters are designed to con­trol the tem­per­a­ture of the coolant in sep­a­rate cir­cuits of the water floor. Thanks to these devices, the nec­es­sary vol­ume of pre­pared water enter­ing the warm water floor sys­tem is pro­vid­ed. In oth­er words, this equip­ment mon­i­tors the amount of coolant in the water heat pipe, and there­fore the func­tion­al­i­ty of the entire heat­ing sys­tem.

Flowmeter functionality

A rotame­ter or, if we give a full def­i­n­i­tion of this unit, a float rotame­ter, at first glance, is an ordi­nary mechan­i­cal device. The design of the prod­uct is based on a plas­tic case (there are mod­els made of brass), inside of which a polypropy­lene float is placed. The case is equipped with a trans­par­ent flask, on which a mark­ing scale is applied. Mov­ing the float up and down inside the device indi­cates a cer­tain val­ue on the scale, which can be used to judge the vol­ume of coolant cir­cu­lat­ing in the pip­ing sys­tem — is it enough for the full oper­a­tion of the heat­ing cir­cuits.

Tra­di­tion­al flow meter for under­floor heat­ing col­lec­tor in var­i­ous ver­sions: on the left — in a plas­tic case, on the right — in brass.

From the point of view of the­o­ry, the heat­ing sys­tem can work with­out this device. In this case, you will have to man­u­al­ly adjust the vol­ume of water enter­ing the cir­cuit, based on per­son­al feel­ings when the air tem­per­a­ture in the room changes.

On a note: by the sound of a run­ning pump and by the inten­si­ty of heat­ing a warm floor, one can judge the degree of use­ful­ness of the sup­ply of hot coolant to all heat­ing cir­cuits.


Refus­ing to use a flow meter when installing under­floor heat­ing is fraught with the fol­low­ing prob­lems:

  • sep­a­rate con­tours of the water floor will be sup­plied with a heat car­ri­er with­out tak­ing into account the char­ac­ter­is­tics of the room, as a result of which the tem­per­a­ture val­ues ​​of the floor sur­face of heat­ed rooms will dif­fer;
  • the con­sump­tion of the ener­gy car­ri­er used to oper­ate the heat­ing devices (elec­tric­i­ty or gas) will be increased.

For exam­ple, you plan to heat the bath­room and the chil­dren’s room at the same time. An autonomous gas boil­er will heat the water for the bath­room and the nurs­ery in the same way, in the same tem­per­a­ture regime. How­ev­er, the bath­room is small­er and will require less boil­er water to heat it than to sup­ply a warm floor in a nurs­ery. It is pos­si­ble to achieve an opti­mal sup­ply of heat car­ri­er for under­floor heat­ing in each room using a flow meter. There­fore, due to the oper­a­tion of this device, it will be pos­si­ble to achieve indi­vid­ual tem­per­a­ture val­ues ​​u200bu200bfor com­fort in the bath­room and chil­dren’s room.

Eval­u­at­ing the oper­a­tion and prin­ci­ple of oper­a­tion of the device, we can draw the fol­low­ing con­clu­sions:

  • the device func­tions com­plete­ly autonomous­ly, with­out requir­ing addi­tion­al pow­er sources;
  • the prin­ci­ple of oper­a­tion of the flow meter allows you to cre­ate the opti­mal flow of coolant for heat­ing cir­cuits, sig­nif­i­cant­ly reduc­ing the ener­gy con­sump­tion of heat­ing devices;
  • the design of the device pro­vides visu­al con­trol over the amount of water in the pipelines;
  • the col­lec­tor, togeth­er with flow meters for under­floor heat­ing, great­ly facil­i­tates the con­trol over the oper­a­tion of the entire sys­tem, is easy to install and unpre­ten­tious in main­te­nance.

Impor­tant! The device is mount­ed strict­ly in a ver­ti­cal posi­tion, sim­ply by screw­ing the device into a spe­cial col­lec­tor sock­et. The device is fixed with a union nut.

On a note: when installing a warm floor, try to achieve the same length of the heat con­duc­tors of all water cir­cuits — despite pos­si­ble dif­fer­ences in con­fig­u­ra­tion, this great­ly sim­pli­fies the adjust­ment of the entire heat­ing sys­tem and allows you to achieve opti­mal tem­per­a­ture para­me­ters.

The principle of operation of the flowmeter. Installation and setup

One of the flowme­ter mod­els with adapter nut


When installing the col­lec­tor and con­nect­ing the heat­ing cir­cuits of under­floor heat­ing, the flowme­ter is placed on a col­lect­ing comb, into which waste water enters. When the tem­per­a­ture of the coolant reach­es the set val­ue, a valve is acti­vat­ed in the back of the col­lec­tor, nar­row­ing or com­plete­ly block­ing the gap for water to enter. In order for the sys­tem to work accord­ing to the described scheme, the pump-mix­ing unit and the col­lec­tor are equipped with ther­mostats.

Flask of the flow meter with the scale of the coolant flow

In order for the water lev­el in the trans­par­ent flask to coin­cide with the hor­i­zon­tal divi­sions of the scale, the device must be in a ver­ti­cal posi­tion. There­fore, for the nor­mal oper­a­tion of the con­trol group, the col­lec­tor should be installed using a plumb or bub­ble lev­el, achiev­ing a strict­ly hor­i­zon­tal posi­tion of the equip­ment com­po­nents. Installing a col­lec­tor with devi­a­tions can cause incor­rect oper­a­tion of the heat­ing equip­ment.

Impor­tant! Fin­ish­ing the premis­es, instal­la­tion of a col­lec­tor cab­i­net can lead to dam­age to indi­vid­ual ele­ments of the mix­ing group, so the units and devices of the heat­ing sys­tem should be locat­ed com­pact­ly.

Instal­la­tion and adjust­ment of instru­ments is car­ried out in accor­dance with the instruc­tions for instal­la­tion and oper­a­tion, usu­al­ly in the fol­low­ing sequence:

  • using a wrench, screw the flow meter into the tech­no­log­i­cal hole of the man­i­fold assem­bly;
  • by rotat­ing the flow meter flask coun­ter­clock­wise, pre­pare the device for oper­a­tion;
  • dis­man­tle the fac­to­ry fuse (usu­al­ly in the form of a ring);
  • set the desired pres­sure by turn­ing the brass ring in the body clock­wise to the desired mark — the loca­tion of the float will demon­strate the adjust­ment;
  • to pre­vent mechan­i­cal dam­age to the device, close the brass ring with a spe­cial over­lay;
  • check the oper­a­tion of the device as part of the entire heat­ing sys­tem.


When oper­at­ing a water heat­ed floor, the flow meter bulb on the man­i­fold must be acces­si­ble to visu­al inspec­tion and, if nec­es­sary, main­te­nance.

Each water cir­cuit con­nect­ed to the col­lec­tor is equipped with an indi­vid­ual flow meter.

The choice of the device mod­el does not par­tic­u­lar­ly affect the qual­i­ty of heat­ing and the func­tion­al­i­ty of the water floor sys­tem — if you fol­low the rules for installing and oper­at­ing floor heat­ing equip­ment, you can achieve the nec­es­sary indi­ca­tors by installing any high-qual­i­ty devices.


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