Mcalpine Bath Waste & Overflow

greyteam1959

I purchased a Mcalpine Bath waste & overflow kit CBWF70CB.
Looking at the installation instructions re the overflow fitting.
It does not make it clear where the flat rubber seal goes on the bath.
On the inside of the bath or the outside ?
Research on Google is split about 50/50 as to where it goes.
Anybody have an answer on here ?
I have actually emailed Mcalpine but no reply as yet.

danrv

On the outside. I have a similar kit.

tacpot12

In this set of instructions: https://mcalpineplumbing.com/wp-content/uploads/2023/11/L-CBWF70CB.pdf

Part 7 goes inside the bath (or can be omitted if you are happy to use silicone under the flange). 
Part 7a goes outside the bath (underneath)
Part 13 goes outside the bath (at the back) 

I would apply silicone to the backside of the flange of whichever overflow grid you are fitting. 

When applying silicone in these situations, it's best to lightly nip up the screws so that you still have a good thickness of silicone under the fitting. You can then wipe away the silicone that has been squeezed out with a tool, but if you then wait for about 12 hours or so, until the silicone has set a bit, you can tighten up the screw fully and you will get a much better seal against the silicone. If you tighten the screws up really tight immediately, most of the silicone gets squeezed out, and in some cases you are left with nothing between the fitting and the bath. Over time this can leak. 

greyteam1959

tacpot12 said:

In this set of instructions: https://mcalpineplumbing.com/wp-content/uploads/2023/11/L-CBWF70CB.pdf

Part 7 goes inside the bath (or can be omitted if you are happy to use silicone under the flange). 
Part 7a goes outside the bath (underneath)
Part 13 goes outside the bath (at the back) 

I would apply silicone to the backside of the flange of whichever overflow grid you are fitting. 

When applying silicone in these situations, it's best to lightly nip up the screws so that you still have a good thickness of silicone under the fitting. You can then wipe away the silicone that has been squeezed out with a tool, but if you then wait for about 12 hours or so, until the silicone has set a bit, you can tighten up the screw fully and you will get a much better seal against the silicone. If you tighten the screws up really tight immediately, most of the silicone gets squeezed out, and in some cases you are left with nothing between the fitting and the bath. Over time this can leak. 

I have those instructions.
Where does it say, or indicate that part 13 goes on the outside of the bath ??

danrv

greyteam1959 said:

tacpot12 said:

In this set of instructions: https://mcalpineplumbing.com/wp-content/uploads/2023/11/L-CBWF70CB.pdf

Part 7 goes inside the bath (or can be omitted if you are happy to use silicone under the flange). 
Part 7a goes outside the bath (underneath)
Part 13 goes outside the bath (at the back) 

I would apply silicone to the backside of the flange of whichever overflow grid you are fitting. 

When applying silicone in these situations, it's best to lightly nip up the screws so that you still have a good thickness of silicone under the fitting. You can then wipe away the silicone that has been squeezed out with a tool, but if you then wait for about 12 hours or so, until the silicone has set a bit, you can tighten up the screw fully and you will get a much better seal against the silicone. If you tighten the screws up really tight immediately, most of the silicone gets squeezed out, and in some cases you are left with nothing between the fitting and the bath. Over time this can leak. 

I have those instructions.
Where does it say, or indicate that part 13 goes on the outside of the bath ??

From what I recall, the washer sits in a recess in the housing. Looked quite obvious to me.
It was the washer orientation that I wasn't sure of but the ridged side I think goes against the bath.

tacpot12

greyteam1959 said:

tacpot12 said:

In this set of instructions: https://mcalpineplumbing.com/wp-content/uploads/2023/11/L-CBWF70CB.pdf

Part 7 goes inside the bath (or can be omitted if you are happy to use silicone under the flange). 
Part 7a goes outside the bath (underneath)
Part 13 goes outside the bath (at the back) 

I would apply silicone to the backside of the flange of whichever overflow grid you are fitting. 

When applying silicone in these situations, it's best to lightly nip up the screws so that you still have a good thickness of silicone under the fitting. You can then wipe away the silicone that has been squeezed out with a tool, but if you then wait for about 12 hours or so, until the silicone has set a bit, you can tighten up the screw fully and you will get a much better seal against the silicone. If you tighten the screws up really tight immediately, most of the silicone gets squeezed out, and in some cases you are left with nothing between the fitting and the bath. Over time this can leak. 

I have those instructions.
Where does it say, or indicate that part 13 goes on the outside of the bath ??

It doesn't say. You could put it on the inside of the bath, but you would see it around the outside of the waste. Silicone on the inside of the bath will be neaterand seal as well as part 13 would if it fitted on the inside. Part 13 fitted on the outside will not seal especially well, as the back of the bath will be rough and Part 13 is plastic rather than soft rubber, so it doesn't mate well with the roughness on the back. 

stuart45

Every plumber I know uses only silicone inside the bath, although most of them tighten up straight away.

greyteam1959

I have put it on the back.

Jumblebumble

greyteam1959 said:

tacpot12 said:

In this set of instructions: https://mcalpineplumbing.com/wp-content/uploads/2023/11/L-CBWF70CB.pdf

Part 7 goes inside the bath (or can be omitted if you are happy to use silicone under the flange). 
Part 7a goes outside the bath (underneath)
Part 13 goes outside the bath (at the back) 

I would apply silicone to the backside of the flange of whichever overflow grid you are fitting. 

When applying silicone in these situations, it's best to lightly nip up the screws so that you still have a good thickness of silicone under the fitting. You can then wipe away the silicone that has been squeezed out with a tool, but if you then wait for about 12 hours or so, until the silicone has set a bit, you can tighten up the screw fully and you will get a much better seal against the silicone. If you tighten the screws up really tight immediately, most of the silicone gets squeezed out, and in some cases you are left with nothing between the fitting and the bath. Over time this can leak. 

I have those instructions.
Where does it say, or indicate that part 13 goes on the outside of the bath ??

Here is a different view agreeing with @Tacpot
You can just see the hatched bit representing the bath poking out  behind the hose
 https://mcalpineplumbing.com/waste-outlet-fittings/bath-wastes/bath-clicker-waste-and-overflow/

As an aside I refuse to use anything else apart from McAlpine as they are so well designed 

greyteam1959

@Jumblebumble
Now the drawing on that link shows exactly where the rubber washer goes.
On the outside.
It is very odd that the instruction included with their fitting does not use that diagram !!