Dilemma that is defying logic....

[carlbos]

Hello,
I have a problem with a shower that seems to have happened for no reason whatsoever.
I recently replaced an en-suite shower enclosure. I retiled, replaced the shower outlet (just the bit that screws into the outlet elbow), hose and shower head.
When I removed the old shower tray I found a very convoluted hot water pipe that had been plumbed around studs in the wall and had 4 right angle joints in it. I replace this with a push fit flexible pipe connector and a smooth curve instead of all the right angles.
I did not alter any of the other plumbing. Thermostatic mixer is the same and remained in its existing place.
The problem: The shower now runs at about half of the pressure that it used to and is not effective at all.
I am on a gravity fed system. There is another shower on the same system in the main bathroom and this operates perfectly fine (as did the en-suite one before). The outlet in the en-suite and the actual shower head is about 20 cm lower than the one in the bathroom and the outlet from the cold water header tank in the loft is 1.8 to 2 metres above.
1. I don’t understand why the pressure has dropped so dramatically.
2. I don’t understand why the pressure in the en suite is so much less than that in the bathroom, as it is slightly lower at the outlet I would expect it to be better.
Other information: The basin tap in the main bathroom had always ran a little slow since I replaced it about 10 years ago but it wasn’t a big issue. When I was replacing the piece of hot water pipe in the en-suite I stopped the cold water feed to the hot water cylinder and then left the taps open to empty the water that was in the pipes. After the plumbing was done I restored the supply. The hot water basin tap has ran about 4 times faster since I did this. Now, the en-suit shower seems to have got the problem that the main bathroom basin tap used to have. Could these be related? Is there anything I can try to resolve?
I consider myself a competent DIYer but I am stuck about what to do from here. Is it worth admitting defeat and getting a plumber in? I am worried that he will just say that a shower pump needs to be fitted. This defies logic because it was fine before and the shower in the main bathroom, on exactly the same system is fine.
Any suggestions greatly appreciated...

 

[Agile]

It could be that you just have an airlock.

Try feeding mains water UP the shower hot supply for a couple of minutes.

Tony

 

[gigz]

It could also be the actual shower head, some are for high pressure systems only.

 

[Agile]

You could well be right!

He confuses pressure with flow too.

But I was giving him some credence when he said he was a competent DIYer and never thought that he would have bought an HP shower head !

Tony

 

[carlbos]

Thanks guys....I have done the airlock clearing and I have tried the original shower head that was on there so those two things are eliminated.

I don't usually confuse pressure and flow (I am a process engineer) but apologies if that wasn't clear in my post.
I am going to have a go at creating a diagram of the system and then maybe post that.

Cheers...

Carl

 

[Onetap]

You've probably added something that has more resistance to the flow of water than what was there previously.

Push-fit fittings? The insert restricts the bore a lot more than soldered fittings.
Shower hose? The bore in some cheapo ones is very small.
Shower inlet filters? May have become blocked with swarf or sediment you'd disturbed.

PS Blockage in the pipes that has moved position? A bit of insulation foam from the cylinder for example? Disconnect shower valve, connect hoses and flush the pipes through.

Full-bore valves (old gate valves) replaced with restrictive, cheap service valves?

 

[Agile]

I don't usually confuse pressure and flow (I am a process engineer) but apologies if that wasn't clear in my post.

Carl

The whole of your first post talked about pressure!

Most people only see the flow rate when using a shower. Your pressure will only be 1-2m with a gravity fed system.

I am sure its the flow rate which you are unhappy with.

Back flushing with mains water should have cleared airlocks and also pushed any debris back from any filters.

The only way is to disconnect the supply pipe and accurately measure trhe flow rate. Then repeat at steps towards the shower head.

Tony

 

[Onetap]

Your pressure will only be 1-2m with a gravity fed system.

Head.

 

[carlbos]

SORTED: I had replaced the shower outlet with a fancy chrome one and inside there was a non return valve. I removed it and everything is fine again now..... Thanks a lot for all the feedback.....