Do I need to keep heating drain valve through airbrick?

[danlightbulb]

A separate point - if you're going to cover the existing airbrick with a concrete step, then you really need to fit a new airbrick somewhere close, so as to keep the underfloor ventilation effective. Otherwise you're risking dry rot slowly taking hold.

There's already 2 more in the same section of wall, one left and one right see picture.

Well I think you should leave it where it is, wrap some tape around it, bury in your concrete step, forget about it and come back here for advice in the future if you ever need to drain your system

I wouldn't be happy with that, it's another bodge.

I'll relocate it when I'm able.

 

[Harry Bloomfield]

There's already 2 more in the same section of wall, one left and one right see picture.

What ever you do, it is essential to ensure there are no isolated corners, with no cross airflow, to avoid the rot. It's not just the number of vents, but their locations too.

In regard to the drain...

Without access to the underfloor area - You could still retain the drain maybe, by devising a removable panel section, in your step. Alternatively, if the vent would be covered by your step.... Break up the vent, and replace the drain cock, with an elbow, to fit an alternative drain cock clear of the step, poking out the side. Add a piece of 100mm plastic pipe, passing into the position of your original vent, through the step, and add a vent cover over the entrance,

The quick, easy means of draining down, is too valuable an asset to simply do away with.

 

[ajstoneservices]

Some people don't know how short life is