HELP! Shower supply (tapped off under bath) needs support

[JetPil0t]

Hello all, as those of you that have read my previous posts will know, I'm spending much more time under my bath than I would care to remember recently.

Anyway, I'm suffering from vibrating pipes under my bath when switching off a tap (full pressure) or when the toilet stops filling (so, a minor water hammer situation really). I think I've figured out a way to remove some of the pipes so that I can clip them, but I'm severely limited in terms of what I can clip once I get behind the bath, as the drill can't fit in there!

PROBLEM: One of the things I've discovered to be contributing to my moving pipe problem is that the top pipe (hot supply) is being pulled down by the dubious way that the hot supply for the shower (GREY PLASTIC PIPE) has been attached to it.
View media item 59395View media item 59396As you can see from the photo, the cold supply pipe uses an 'elbow' and is supported by the floor. However the hot supply is not supported, so it pulls the corresponding supply pipe down, and without enough clips, this is causing movement when full pressure is suddenly removed. In fact the hot pipe gets pulled down to rest on top of the cold pipe, so when full cold pressure is removed, BOTH pipes vibrate.

I'm sure this is not good and I'd like to fix it. This shower to supply pipe connection looks like a compression fitting - am I right? I did some homework on how these work, but if someone could suggest the right parts to buy and sequence to connect them in, such that the hot supply ends up looking like the cold (ie: supported by the floor) I would appreciate it!

NOTE: I can't use a 'straight down to the floor' connection for the hot, because the cold supply pipe is in the way.

Would appreciate any help, getting desperate to get the tile back on the bath now!

 

[onecog]

Leave 50mm of grey pipe coming from the compression tee then an elbow facing the floor,small length of pipe to floor then an elbow facing the same way as the cold elbow and join onto the existing grey pipe and clip it to the floor.

 

[onecog]

Don' forget to use inserts with any plastic pipe used.

 

[JetPil0t]

Thanks for the reply. I assume I need a compression elbow (rather than plastic) and I also need the corresponding 2x plastic compression rings for each section of pipe?

Also, clip it to the floor - really? Space is a bit cramped in there to drill - any suggestions?

Finally, you may or may not be able to see there's an isolation valve on the hot supply line - which section of pipe should I put that in - I'm hoping the section on the floor would be OK, since that's going to be the longest by far!

 

[onecog]

If you buy 2 pushfit elbows and 4 inserts you won't need anything else except the short length of pipe to get you to the floor(copper or plastic).
If you use copper then you only need 2 inserts.
Leave the iso valve where it is to save complications
forget the clipping if it's to difficult,I thought it was a timber floor or you cold gripfill 2 strips of wood (10mm ply) under the pipes and clip to that using nail clips.

 

[Diyisfun]

The easiest way without touching the fittings, get some timber and build up under the pipe that will support it, you can screw it down & have no leaks.

 

[JetPil0t]

Thanks both for the suggestions. Yep sadly the floor is concrete. From what you've said I'm gathering the idea is to use pushfit rather than compression to build the 'double elbow' structure down to the floor - seems reasonable, as long as the connections hold over time!

I had thought about the timber and nail clips idea, but couldn't think of a way to adhere the timber to the floor. Gripfilling should work then? I've never used it - anyone care to recommend a good brand?

 

[JetPil0t]

Help. Oh dear I wish I had never tackled this job. Got all the pipes removed, clipped in and put back together now. Then thought oh well, I may as well use 2x speedfit elbows to take the gravity load off of that (see grey pipe in photos) hot supply for the shower.

I now have everything in pieces and I've cut the grey pipe (short section between isol valve and equal tee / 3 way couple). As expected, this supply is joined with compression fittings and copper olives.

What I didn't expect to see is METAL inserts in the grey pipe. I've now discovered that the copper olives I bought to connect my speedfit plastic sections to the compression fittings (to connect my new elbow from the main supply, to the grey shower supply) are too loose around the plastic speedfit pipe and as a result nothing joins up! The plastic speedfit pipe I bought (15mm Class S barrier pipe) seems to be slightly 'thinner' than the original grey pipe (also marked as Class S barrier pipe)

Any ideas what's gone wrong here and how I can fix it?? Half a mind to go to B&Q and pick up a section of this grey pipe and just connect everything back the way it was!

 

[onecog]

I suggest you bet
On His Own & Join Together
in tomorrows grand national

 

[JetPil0t]

Haha... Good idea

Anyway, not to worry, it turns out I was being absolutely stupid and just needed to apply a bit more brute force to solve the problem. Pipes are actually the same size!

I will now retreat to my corner

 

[danplumb]

Haha... Good idea

Anyway, not to worry, it turns out I was being absolutely stupid and just needed to apply a bit more brute force to solve the problem. Pipes are actually the same size!

I will now retreat to my corner

Did it solve your water hammer problem ?