Please help me understand my heating system - One Pipe Open Vent System

[JackK]

The system is probably pumped CH with gravity HW, certainly going by the size of the HW primary.

Ideally you want someone who is experienced with 1 pipe systems to come and have a look to determine how the system is set up. If it is a 1 pipe and you are not in a position to change to a 2 pipe then it needs careful control and balancing.

Unfortunately you can't just drop a new designer column rad onto the system and expect it to work, in fact you can't just drop any new rad onto the system and expect it to work, it needs an experienced bod to fit as it need to be piped in a specific way/position and then the system needs balanced again.

Thank you - Can you also quickly answer whether you would also rip out the system? It works and must have cost a bomb to install when put in. Is it really a good idea to replace with plastic two pipe and will it make that much of a difference?

Can you also confirm this is called gravity HW when the flow is pumped up but the return is left to itself to come back to boiler

Thank you so much !

 

[Madrab]

Is it really a good idea to replace with plastic two pipe and will it make that much of a difference?

Doesn't have to be plastic, though it is easier/quicker to lay and invariably cheaper then copper. A 2 pipe system is much better than a one pipe system and much easier to manage. The HW can also be connected in too the same system and the system becomes fully pumped and can be better controlled with separate HW and CH controls.

Can you also confirm this is called gravity HW when the flow is pumped up but the return is left to itself to come back to boiler

If you have a pump on the CH side of the boiler and separate set of large pipes with no pump on the HW side then yes that's - Gravity HW with pumped CH.

 

[JackK]

Doesn't have to be plastic, though it is easier/quicker to lay and invariably cheaper then copper. A 2 pipe system is much better than a one pipe system and much easier to manage. The HW can also be connected in too the same system and the system becomes fully pumped and can be better controlled with separate HW and CH controls.


If you have a pump on the CH side of the boiler and separate set of large pipes with no pump on the HW side then yes that's - Gravity HW with pumped CH.

Hi again - Thank you

You are more experienced then I am

I have a pump on a shared CH and HW flow pipe and a separate return for the CH and a separate return for the HW.

Is this a gravity system in that case ?

 

[fixitflav]

Just a comment - this system has been discussed at some length in several threads over the past year. Anybody who has the time to spare, might be worth reading some of that for background.

 

[Madrab]

I have a pump on a shared CH and HW flow pipe and a separate return for the CH and a separate return for the HW.

ok so if the HW is on the same flow pipe as the CH and they are both connected to the pump then no, it's a fully pumped system.

 

[Agile]

Correctly piped then I would expect that most fancy column rads would work on a one pipe system. Although they might need a baffle fitting within the bottom.

Many boiler manufacturers seem frightened of one pipe systems even though their boilers can usually work on a properly designed one.