Out of interest, what is a one pipe system?

[ericmark]

I note at work we do have a one pipe system, steam goes in one end, and water dribbles out the other end, there is no return, but somehow I can't see that is what people call a one pipe system, does not matter if in series or parallel you need two pipes to every radiator, but I notice some radiators have four pipes, two for heating and two for cooling, so is no cooling, what is meant?

I have only seen one house with a one pipe system, the works engineer had connected his house to the works' boiler, so his heating had a steam inlet, in fact only house I have ever seen heated from a boiler, all the rest the water did not boil, so clearly not a boiler.

But I see the phrase one pipe system, I am sure not connected to steam line, so what is it?

 

[big-all]

one pipe in steam heat terms means
steam from the loco [clayton or stone boiler on br deisel]has to flow this is caused by a controlled leak at the train end to allow movement so steam will flow
in a one pipe domestic system you have a loop with 2 choice one is flow via the radiator tapping off the flow and get heat or not to tap off the pipe but returning to the boiler to be reheated via the same pipe
rather than a 2 pipe system where the input should always be on the flow side and the radiator output is always on the return side

in general iff you have 4 pipes you will tend to have 2 circuits with the ability to shut off and control a whole group like up stairs and down stairs

 

[ericmark]

From what you are saying, you seem to be describing is the heating found in schools and collages, where each radiator has a restricted bypass? With two pipes, but arranged in series not parallel, this arrangement also used with fan assisted radiators, the water always flows through the radiator, but only gets into the room when the fan is running. Some have twin matrixes one to heat and one to cool, seen them advertised, the Myson iVector, but not seen them used. But be it in series or parallel, they both have two pipes.

The steam heating yes, that is what we have where I volunteer, and that is clearly a one pipe system.

I can see how with TRV control we want parallel, and with fan speed control we want series, as with the latter you want a reasonable quantity of water through the radiator at all times, but much depends on the water maximum temperature, with a gas or oil heater, we want the return water cool enough to extract the latent heat from flue gases, with a heat pump, the return temperature is not so important, what we want is a method to reduce the radiators physical size, so the fan assisted radiators work well, so with a heat pump, series or parallel does not matter, but with no control of water flow rate in a fan assisted radiator having them in series means you don't get hot water returned due to one fan not running.

But as found in school, those rooms at the end of the run tend to be cooler, which can be compensated for by using larger ones at the end of the run, I am sure water flow rate controls could be added to fan assisted radiators, but before we had condensing water heaters, it was not really required.

However, "series" or "parallel" is very discriptive one is left with no ambiguity. Same applies to furnace, or water heater, where boiler to my mind produces steam. But we all know the unit used at home does not boil water, so calling it a boiler, does not really matter, I know what it is, but one pipe and two pipe systems, I am only guessing, hense the question.

 

[denso13]

One pipe, circulating hot water round the system.