Are hot water radiators bi-directional?

[utkmatt]

I have a 1920's hot water radiator system in my house. Recently I had a plumber do some work, and he installed the radiator backwards from the way it was before. now it makes a tapping noise. I have two theories of what may be causing the tapping noise.

1. It might be the pipes below the radiator are expanding/contracting, and maybe wrapping them in foam pipe insulation would help keep it from tapping?
2. It might be that the radiator is not bi-direction, and the plumber installed it backwards.

Please let me know if you can install these radiators backwards? The way it is now, the air release valve at the top is on the same side where the hot water is entering the radiator from the boiler.

Thanks for your help!

 

[bengasman]

What do you mean by: "installed backwards"?

 

[MJN]

It doesn't matter what side the bleed valve is on. What might matter is the position of the thermostatic valve, if fitted, relative to the flow. Some, usually older ones, can whistle/chatter if fitted on the return due to the way the valve operates.

You sound description of tapping however makes me think it's another issue - perhaps expansion/contraction of the radiator on the wall brackets. Fitting styles may differ over there but here it is common for the wall brackets to have plastic spacers between them and the radiator in order to avoid the metal-on-metal contact making a noise as one expands slightly relative to the other. Insulation tape or similar can also be used to good effect.

Alternatively, as you suggested it might also be the pipes rubbing against something. You'd have to try and work out where the noise is coming from as obviously here we can only give theoretical suggestions.

Mathew