Is it ok to run a combi boiler (Vailant) if I remover the rads

[Yukster]

Is it ok to run a combi boiler (Vailant) if I remover the rads and put stop ends instead?

 

[polesapart]

yes

If your model is relatively new (ecoTec Pro or Plus) just isolate the flow and return on the valves underneath the boiler before draining system, no need to cap.

( On some of the older variants this is not recommended and capping would be the safer option. The isos can leak if disturbed.)

Obviously switch to summer mode.

 

[Yukster]

yes

If your model is relatively new (ecoTec Pro or Plus) just isolate the flow and return on the valves underneath the boiler before draining system, no need to cap.

( On some of the older variants this is not recommended and capping would be the safer option. The isos can leak if disturbed.)

Obviously switch to summer mode.

It is an Ecotec plus 831 R1 boiler. What do the flow and return on the valves underneath the boiler? Are these the two white ones and if so, am i right in thinking that it is isolated?

What is the right way to fill up the system again when I re-fit the rads or bridge the rads pipes?

 

[bernardgreen]

just isolate the flow and return on the valves underneath the boiler

What about expansion of water in the heat exchanger when the boiler fires up for hot water demand,

If the expansion vessel is isolated from the water in the heat exchanger then there is no where for the expanding water to go.

Maybe the volume of water in the heat exchange is too small for un-relieved expansion to be a problem.

 

[ianmcd]

No not the white ones, the two larger pipes 22mm marked CH Flow and CH return, the white ones are your filling loop you open these to top the pressure up, Forget what Bennyboy said about the expansion vessel, it will still be connected with the Isolating valves closed

 

[bernardgreen]

about the expansion vessel, it will still be connected with the Isolating valves closed

So in all Vailant boilers there is an expansion vessel integral to the boiler.

 

[Yukster]

No not the white ones, the two larger pipes 22mm marked CH Flow and CH return, the white ones are your filling loop you open these to top the pressure up, Forget what Bennyboy said about the expansion vessel, it will still be connected with the Isolating valves closed

Thanks. Is it a problem is I drained the system without isolated the Ch flow and Ch return valves?

 

[ianmcd]

So in all Vailant boilers there is an expansion vessel integral to the boiler.[/QUOTE
Not all vaillants but on that one there is

 

[ianmcd]

Thanks. Is it a problem is I drained the system without isolated the Ch flow and Ch return valves?

you wont get the HW to work if there is no pressure in the boiler

 

[Yukster]

you wont get the HW to work if there is no pressure in the boiler

Once I refill the boiler up to predure, would it work ok despite not closing the isolation valves when I drained the system?

 

[ianmcd]

yes

 

[dilalio]

You'll need to fill the system again and, make sure the boiler is full of water and not air. This should happen via the internal AAV but depends on where the boiler is in the system... As a layman, it'd be better for you to make sure the whole system is filled and bled of air, run it and when you're sure the boiler contains water then isolate the flow and return, and then drop the system.