Do-it-yourself single-pipe heating system of a private house


A sin­gle-pipe heat­ing sys­tem exists as an alter­na­tive to a two-pipe sys­tem. Hav­ing a com­pa­ra­ble effi­cien­cy, dis­trib­ut­ing the coolant through a sin­gle pipe is a more eco­nom­i­cal option, since it becomes pos­si­ble to save on pipes and fit­tings. For self-cal­cu­la­tion and assem­bly of such heat­ing, you should care­ful­ly study the prin­ci­ples of oper­a­tion and meth­ods of instal­la­tion of its con­stituent ele­ments.

Features of a single-pipe heating system

single pipe system with return

A sin­gle-pipe heat­ing sys­tem is actu­al­ly a closed ring of pipes through which the coolant cir­cu­lates. In addi­tion to the pipes them­selves, there are two main ele­ments in the heat­ing main: a boil­er and heat­ing radi­a­tors. In addi­tion, the sys­tem includes a man­i­fold, shut-off and con­trol valves, a safe­ty group, an expan­sion tank, etc. aux­il­iary equip­ment.

The water heat­ed by the boil­er enters the main and is fed to the first heat­ing radi­a­tor. After leav­ing it, the water is sup­plied through the main to the sec­ond heat­ing radi­a­tor, etc. from the last radi­a­tor, the coolant returns to the boil­er through the return pipe and the cycle repeats.

Since in each of the radi­a­tors, due to inten­sive heat exchange, the tem­per­a­ture of the coolant decreas­es, the heat­ing of the last radi­a­tor will be min­i­mal, while the first radi­a­tor may have the tem­per­a­ture at which the boil­er is set.

This moment is the main fea­ture of sin­gle-pipe sys­tems. With an alter­na­tive two-pipe scheme, the coolant is dis­trib­uted almost with­out loss of tem­per­a­ture through the sup­ply pipe, from which water is tak­en through the branch­es to the radi­a­tors. There­fore, the tem­per­a­ture of each of the radi­a­tors will be almost the same. The appear­ance of some dif­fer­ence is pos­si­ble only with a large length of the line.

There are three ways to solve the prob­lem of insuf­fi­cient heat­ing of the last radi­a­tor in the ring of a sin­gle-pipe sys­tem:

how to solve the problem of uneven heating

  1. Raise the water tem­per­a­ture. This method is the eas­i­est to imple­ment, but in prac­tice it is rarely used due to the increase in ener­gy costs. In addi­tion, there may be a prob­lem of over­heat­ing of the first radi­a­tors in the sys­tem.
  2. Increas­ing the heat out­put of the ter­mi­nal heaters. This is achieved by increas­ing the num­ber of sec­tions, which entails a sig­nif­i­cant increase in the cost of the entire struc­ture.
  3. Inclu­sion in the cir­cu­la­tion pump sys­tem. With an inten­sive cir­cu­la­tion of the coolant, it does not have time to ful­ly give off ener­gy in the first radi­a­tors and is sup­plied hot even to the last heat exchang­ers. This method is the most com­mon, because. small costs for the cir­cu­la­tion pump are ful­ly com­pen­sat­ed by the abil­i­ty not to increase the inten­si­ty of the boil­er and do with­out pow­er­ful radi­a­tors in the last heat exchang­ers along the ring.

One-pipe heat­ing scheme has the fol­low­ing advan­tages before alter­na­tive schemes:

  • sig­nif­i­cant reduc­tion in pipe con­sump­tion and com­po­nents, which great­ly reduces the cost of the entire assem­bly;
  • Pos­si­bil­i­ty to con­nect heaters both in series and in par­al­lel;
  • you can direct the coolant so that it first enters the rooms with the great­est heat loss.

At the same time, sin­gle-pipe options are also inher­ent some short­com­ings:

  • long warm-up the total vol­ume of the coolant after a cold start;
  • if the house has two or more floors, then the heat­ing sys­tem will be quite dif­fi­cult to bal­ance. The upper floors will always warm up more effi­cient­ly than the low­er ones.
  • if it is nec­es­sary to repair one sec­tion, you will have to turn it off the whole sys­tem.


The main fea­ture by which sin­gle-pipe heat­ing options can dif­fer is the coolant cir­cu­la­tion scheme.

Vertical layout

vertical system

Its fea­ture is the use of ver­ti­cal ris­ers and the pos­si­bil­i­ty of instal­la­tion in mul­ti-storey build­ings. In this case, the heat­ing heat exchang­ers are con­nect­ed in series, start­ing from the top floor. In addi­tion, the pres­ence of a ver­ti­cal ris­er allows you to orga­nize a grav­i­ty assem­bly that does not require the use of a cir­cu­la­tion pump.

The coolant here will begin to move, flow­ing down under the influ­ence of grav­i­ty along hor­i­zon­tal sec­tions of pipes with a cer­tain slope. In addi­tion, the coolant will addi­tion­al­ly move the force that occurs in the ver­ti­cal ris­ers due to the dif­fer­ence in the den­si­ty of the coolant with dif­fer­ent tem­per­a­tures.


It is used only in one-sto­ry hous­es. It can be either grav­i­ty or forced cir­cu­la­tion. All heat­ing radi­a­tors in hor­i­zon­tal sys­tems are con­nect­ed in par­al­lel. It is pos­si­ble to cre­ate cir­cuits with sev­er­al loops con­nect­ed through a col­lec­tor.

In addi­tion, there is a vari­ant of sin­gle-pipe heat­ing, in which the coolant pass­es not only through the radi­a­tor, but also in par­al­lel through a small diam­e­ter pipe.

This allows you to cre­ate longer loops due to more effi­cient heat dis­tri­b­u­tion along the entire length of the heat­ing line. Such a scheme is called “Leningrad”.

Ways to connect radiators

Most mod­els of radi­a­tor assem­blies allow you to con­nect two of the struc­tural­ly pro­vid­ed points: at the top and bot­tom on the sides of the radi­a­tor.

There are sev­er­al basic con­nec­tion types:

  • diag­o­nalwhen the sup­ply pipe is includ­ed in the upper inlet on one side of the heater, and the out­let pipe is con­nect­ed to the low­er one on the oppo­site side. This is the most effi­cient way;
  • sidein which the coolant is sup­plied and removed through a pair of holes locat­ed on one side of the heat exchang­er;
  • low­erwhen water enters and exits the radi­a­tor through the bot­tom pair of holes;
  • sin­gle point con­nec­tion. It is used only in extreme cas­es, when it is not pos­si­ble to extend a sec­ond pipe to the radi­a­tor. For such a con­nec­tion, spe­cial injec­tor con­nec­tion units, in which the pipes enter­ing the radi­a­tor hole have dif­fer­ent lengths.

Mounting technology

The sequence of actions when assem­bling a one-pipe sys­tem is divid­ed into sev­er­al stages:

    • boil­er instal­la­tion. Depend­ing on its type and design, instal­la­tion can be done either on the wall or on the floor. In any case, all fire safe­ty rules must be observed;

boiler installation

    • instal­la­tion of a safe­ty group con­sist­ing of a safe­ty valve, an air vent and a pres­sure gauge. The safe­ty valve ensures the dis­charge of the coolant when its pres­sure in the sys­tem ris­es above the estab­lished norm. The air vent auto­mat­i­cal­ly removes air from the heat­ing line. The pres­sure gauge dis­plays the actu­al pres­sure in the pipes. Install the safe­ty group imme­di­ate­ly after the boil­er. It is strict­ly for­bid­den to install shut-off valves between the boil­er and the safe­ty group;

security group installation

    • pipeline assem­bly. For a grav­i­ty one-pipe scheme, after the boil­er of the safe­ty group, a ver­ti­cal col­umn of pipes of a larg­er diam­e­ter must fol­low than in the main line. The hor­i­zon­tal part of the high­way should have a con­tin­u­ous slope of sev­er­al degrees. Pipes can be either entire­ly met­al, or met­al-plas­tic, or rein­forced polypropy­lene;

pipe assembly

    • radi­a­tors are mount­ed in the places deter­mined by the project. Most often, mount­ing brack­ets mount­ed on the wall are used for this. With a diag­o­nal con­nec­tion, it makes sense to orga­nize a slope of one or two degrees towards the drain. Unused open­ings are closed with plugs, a Mayevsky crane is installed in one of them to dri­ve away air con­ges­tion;

battery mounting

    • a return pipe is con­nect­ed to the out­let of the lat­ter in the ring, sup­plied to the boil­er inlet;

return pipe installed

    • an expan­sion tank cuts into the return line through the tee. Its capac­i­ty is select­ed depend­ing on the type of vol­ume of the cir­cu­lat­ing coolant. For water, you should choose tank mod­els with a capac­i­ty of about 10% of the vol­ume poured into the pipes. For non-freez­ing, the tank must have a capac­i­ty of 20–25% of the vol­ume used;

expansion tank

  • if nec­es­sary, return cir­cu­la­tion pump. The pump pow­er is select­ed indi­vid­u­al­ly, based on the vol­ume and fea­tures of the exist­ing assem­bly. It is not rec­om­mend­ed to use pumps with excess pow­er, since this will not improve the oper­a­tion of the heat­ing, but will lead to its air­ing and noise;
  • through a tee in the low­est part of the return pipe, a drain is con­nect­ed with a tap to drain the coolant.

weir taps

System technology

The char­ac­ter­is­tic fea­tures of sin­gle-pipe sys­tems fol­low from their ring scheme and the sequen­tial pas­sage of the coolant through the radi­a­tors. First of all, it is an inevitable fact that the tem­per­a­ture of the last heater and return will always be much low­er than in the first radi­a­tor.

Oth­er fea­tures are most clear­ly man­i­fest­ed in grav­i­ty struc­tures.

  1. The expan­sion tank must not be installed on the return, but at the high­est point of the ver­ti­cal col­umn after the boil­er. In this case, the tank can be of an open type.
  2. The boil­er inlet should be as low as pos­si­ble.. Ide­al­ly below floor lev­el.
  3. The entire line after the ver­ti­cal col­umn must have a con­tin­u­ous slope. An ele­vat­ed sec­tion of the pipeline can stop the sys­tem due to the accu­mu­la­tion of air and vio­la­tion of the flow of water under the influ­ence of grav­i­ty.

There­fore, at the plan­ning stage, all these fea­tures should be tak­en into account.


On the net­work you can find a lot of reviews about the expe­ri­ence of oper­at­ing sin­gle-pipe heat­ing sys­tems. Here are the most char­ac­ter­is­tic of them:

Hope, Nizh­ny Nov­gorod

We have been using this sys­tem for sev­er­al years. Attracts the abil­i­ty to inde­pen­dent­ly reg­u­late the tem­per­a­ture. Of the incon­ve­niences, only that in severe frosts, water begins to evap­o­rate from an open expan­sion tank. So it has to be topped up peri­od­i­cal­ly.

Roman, Pen­za

The sys­tem does not cause any prob­lems dur­ing oper­a­tion. I use antifreeze as a coolant. So that in the event of a pos­si­ble repair it would not be nec­es­sary to drain it entire­ly, I con­nect­ed the radi­a­tors to the “Amer­i­can” and installed the taps.

Single pipe heating: video

This video shows the process of assem­bling sin­gle-pipe heat­ing in a cot­tage

As fol­lows from the reviews and the very essence of the sin­gle-pipe heat­ing sys­tem, such a solu­tion can be a good option for a small house.

The min­i­mum mate­r­i­al con­sump­tion, the pos­si­bil­i­ty of refus­ing ener­gy-depen­dent cir­cu­la­tion pumps and, at the same time, good ther­mal effi­cien­cy, all this makes sin­gle-pipe heat­ing very attrac­tive for own­ers of sub­ur­ban real estate.

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