What's the purpose of this strange return pipe?

pieroabcd

Hi,
In the kitchen the return pipe has a kind of angled deviation.
What's it's purpose?
Since on it sits the TRV I want to move it to the other end, in order to have the TRV on the flow. 
Is there anything preventing it due that angled deviation? It makes me think of a flushing system and I definitely don't want to trigger it doing the wrong thing.

Thanks

Ayr_Rage

pieroabcd said:

Hi,
In the kitchen the return pipe has a kind of angled deviation.
What's it's purpose?
Since on it sits the TRV I want to move it to the other end, in order to have the TRV on the flow. 
Is there anything preventing it due that angled deviation? It makes me think of a flushing system and I definitely don't want to trigger it doing the wrong thing.

Thanks

A picture of the pipe would be helpful.

WIAWSNB

We need photos. 
Modern TRVs are bi-directional, so that bit should be ok. Since the rad is close to the boiler, it'll receive a powerful flow, so the lockshield will need tweaking right down.

pieroabcd

Dirty, I thought that I had inserted it 

Is it a drain valve?

Grumpy_chap

That's a drain point.

pieroabcd

Ive Just noticed a bolt under the straight part. I imagine that it's the opening valve?

bryanb

pieroabcd said:

Ive Just noticed a bolt under the straight part. I imagine that it's the opening valve?

There are no bolts in the pictures

HHarry

pieroabcd said:

Ive Just noticed a bolt under the straight part. I imagine that it's the opening valve?

Yes - they usually have a square head.  A word of caution, once opened they don’t always seal very well if the rubber washer has perished or some grit gets stuck in it.

GDB2222

How much difference does it make in practice whether the TRV is on the flow or return? It seems a faff to drain the system down just for a small improvement. 

Despite that drain point, I can’t see what’s stopping you swapping the two valves round? Are they the same size? 

pieroabcd

Yes same size.
I don't think that it makes any improvement in practice, but having a uniform system with all valves if the same type and in the same position has its advantages (like if you call a plumber they won't have excuses) and if in the future it comes to sell (not planning at all) at least I won't leave behind the disasters that I found when i bought the house two years ago.
Anyway, no need to drain the system: the valves can be just unscrewed and inverted.

WIAWSNB

Check that valve body carefully for a double-headed arrow or similar, to indicate bi.

And, are you sure it's on the return? 

To swap the valves around should be straightforward if they have the same dims, but your system will need to be drained. 

That's a good thing, because it seems clear from your other thread that cleaning is required, and the simplest way is to add chemicals, run it for a fortnight, and then fully drain. 

The 'valve' for that drain point is located up inside the bottom part, and good chance a radiator bleed key will fit.

If it does drip after use - good chance it'll be fine - then you unscrew the whole 'valve' part, and replace the washer. Very simple.

If you are going to be doing regular plumbing DIY like this, worth getting a tube of silicone grease, and giving every rubber thing and thread a smear on reassembly.