8ball Posted June 1, 2019 Share Posted June 1, 2019 I have purchased a Grohe Thermostatic shower with an exposed bar mixer and have been trying to get my head around the fitting of the mixer bar to the hot and cold supply with the 1/2 to offset 3/4 BSP threaded parts supplied. This is the only helpful video I could find from Grohe showing how to fit the shower but it does not go into detail about the fittings needed to connect the 1/2 to offset 3/4 part to. I was going to ditch the offset fittings supplied by Grohe and get a Bristan Bar Valve wall mount as in the pic below which would enable me to fit the bar mixer with its 3/4 fittings directly to it. After getting the Bristan part home I realised that the 3/4 BSP threads had a measurement of 30mm in length and I need at least 34 - 42mm so I returned the part back to screwfix and started searching for a shower wall plate that had the 3/4 fixings but with the longer thread but I cannot find such an item. It seems the standard length is 30mm all the fitting kits. So back to using the parts supplied by Grohe which are: So with my limited knowledge of plumbing which stretches to JG speedfit what parts do I need to enable me to fit these stupid Grohe parts. I'm fitting the shower to plasterboard wall with a tile covering so the thickness should total about 24mm and will have no access to the rear as its a solid wall. Any help would be fantastic as at the moment as I feel like having a nervous breakdown from the week I've had. 1 Link to comment Share on other sites More sharing options...
Onoff Posted June 1, 2019 Share Posted June 1, 2019 (edited) OK, the 1/2" offset end fits over your 15mm copper pipe feeds like this: The 15mm pipe goes in a good way so you could in theory go in less so as to gain more projection. Not shown the nut, olive, ptfe tape and or compound (I use Jet Blue Plus) which I can mock up if you want? You put one spanner on the flats of your 3/4" bit. Another spanner on the nut at the 1/2" joint. Make sense? Edited June 1, 2019 by Onoff Link to comment Share on other sites More sharing options...
ProDave Posted June 1, 2019 Share Posted June 1, 2019 Why do you need the 3/4 thread longer than 34mm? @Onoff you can't normslly fit copper pipe in like thst, it does not have the machined "cone" to take an ollive. You normally screw a pair of these https://www.screwfix.com/p/endex-end-feed-adapting-90-wall-plate-elbow-15mm-x/83561 to the wall. You can get compression fitting versions but don't have time to search for one. Then the offset of the adaptors allows you to fine tune the spacing for the bar mixer if you have not got it exactly right. Link to comment Share on other sites More sharing options...
8ball Posted June 1, 2019 Author Share Posted June 1, 2019 5 minutes ago, Onoff said: OK, the 1/2" offset end fits over your 15mm copper pipe feeds like this: The 15mm pipe goes in a good way so you could in theory go in less so as to gain more projection. Not shown the nut, olive, ptfe tape and or compound (I use Jet Blue Plus) which I can mock up if you want? You put one spanner on the flats of your 3/4" bit. Another spanner on the nut where at the 1/2" joint. Make sense? Thanks for the reply Onoff, so how would I manage to fix the 90 degree fitting to the wall inside the cavity where my pipes come up from the floor as the whole weight of the shower mixer bar sits on the hot and cold connection? So is the 1/2 bsp is just a standard compression fitting as on a radiator so I can go and take a nut from an old 1/2 fitting and then use a new olive? Link to comment Share on other sites More sharing options...
8ball Posted June 1, 2019 Author Share Posted June 1, 2019 (edited) 28 minutes ago, ProDave said: Why do you need the 3/4 thread longer than 34mm? @Onoff you can't normslly fit copper pipe in like thst, it does not have the machined "cone" to take an ollive. You normally screw a pair of these https://www.screwfix.com/p/endex-end-feed-adapting-90-wall-plate-elbow-15mm-x/83561 to the wall. You can get compression fitting versions but don't have time to search for one. Then the offset of the adaptors allows you to fine tune the spacing for the bar mixer if you have not got it exactly right. As in my pics the shrouds are 35mm in depth + 1mm for the seal up against the tile so the thread needs to be between 34 - 42mm to putrude through to enable the connection of the mixer bar fixings. If the thread is 30mm it doesn't clear the shroud and you cant tighten the 3/4 bolt from the mixer bar. Edited June 1, 2019 by 8ball Link to comment Share on other sites More sharing options...
ProDave Posted June 1, 2019 Share Posted June 1, 2019 Ah, I see. The square bit that fits on the wall is unusual. Link to comment Share on other sites More sharing options...
8ball Posted June 1, 2019 Author Share Posted June 1, 2019 OK so I'd like to fit this wall plate elbow behind the plasterboard cavity which could take the 1/2 supplied Grohe fitting, Grohe fitting BUT Link to comment Share on other sites More sharing options...
8ball Posted June 1, 2019 Author Share Posted June 1, 2019 11 minutes ago, ProDave said: Ah, I see. The square bit that fits on the wall is unusual. I though buying Grohe would have a good design and easy fitting but I really regret it now? Link to comment Share on other sites More sharing options...
8ball Posted June 1, 2019 Author Share Posted June 1, 2019 I need some kind of extension in between the wall plate elbow and the Grohe fitting Link to comment Share on other sites More sharing options...
PeterW Posted June 1, 2019 Share Posted June 1, 2019 1 minute ago, 8ball said: I need some kind of extension in between the wall plate elbow and the Grohe fitting £2 and 5 mins... Get a couple of each of these, PTFE and a spanner and thread into your wallplate fitting and Robert is your grandmothers son in law... 1 1 Link to comment Share on other sites More sharing options...
ProDave Posted June 1, 2019 Share Posted June 1, 2019 8 minutes ago, 8ball said: I though buying Grohe would have a good design and easy fitting but I really regret it now? It is a long time since I fitted Grohe. Years ago I would have agreed, now I don't know. Just like 20 years ago I would have said MK made the best electrical fittings. I don't say that now. It is a bit poor if Grohe have supplied a kit that does not work together. I question are you assembling it correct;ly? The nut that joins the fitting to the 3/4 nipple is plain brass. That suggests it is not meant to be seen, if it was, it would be chrome plated. I wonder if somehow that is meant to end up concealed inside the square chrome bit, in which case you might not need the extension you are seeking? Can you post the instalation instructions? Link to comment Share on other sites More sharing options...
8ball Posted June 1, 2019 Author Share Posted June 1, 2019 6 minutes ago, PeterW said: £2 and 5 mins... Get a couple of each of these, PTFE and a spanner and thread into your wallplate fitting and Robert is your grandmothers son in law... Now that's what I'm talking about, Thanks PeterW. do these fittings have a washer or an olive in between them or is it just a bit of PTFE tape as you suggested Link to comment Share on other sites More sharing options...
8ball Posted June 1, 2019 Author Share Posted June 1, 2019 6 minutes ago, ProDave said: It is a long time since I fitted Grohe. Years ago I would have agreed, now I don't know. Just like 20 years ago I would have said MK made the best electrical fittings. I don't say that now. It is a bit poor if Grohe have supplied a kit that does not work together. I question are you assembling it correct;ly? The nut that joins the fitting to the 3/4 nipple is plain brass. That suggests it is not meant to be seen, if it was, it would be chrome plated. I wonder if somehow that is meant to end up concealed inside the square chrome bit, in which case you might not need the extension you are seeking? Can you post the instalation instructions? The shroud has a little sleeve inside it which after fitting you pull out over the 3/4 nut ? Link to comment Share on other sites More sharing options...
ProDave Posted June 1, 2019 Share Posted June 1, 2019 1 minute ago, 8ball said: The shroud has a little sleeve inside it which after fitting you pull out over the 3/4 nut ? Looks like you do need the extension bits. Very poor to supply something that won't work properly. Link to comment Share on other sites More sharing options...
8ball Posted June 1, 2019 Author Share Posted June 1, 2019 8 minutes ago, ProDave said: Looks like you do need the extension bits. Very poor to supply something that won't work properly. Just found these and what a rip off for 2x 20mm bits of chrome plate threaded pipe, I like PeterW's idea better as the extension is hidden behind the wall and shroud anyway https://www.showerdoc.com/grohe-07130-20mm-extension-piece-0713000m Link to comment Share on other sites More sharing options...
Onoff Posted June 1, 2019 Share Posted June 1, 2019 2 hours ago, ProDave said: Why do you need the 3/4 thread longer than 34mm? @Onoff you can't normslly fit copper pipe in like thst, it does not have the machined "cone" to take an ollive. You normally screw a pair of these https://www.screwfix.com/p/endex-end-feed-adapting-90-wall-plate-elbow-15mm-x/83561 to the wall. You can get compression fitting versions but don't have time to search for one. Then the offset of the adaptors allows you to fine tune the spacing for the bar mixer if you have not got it exactly right. Bugger...have I given him a bum steer? Sorry @8ball! Literally just done mine at Xmas will. My mixer and the offset fittings above were Bristan I think but I didn't use them hence having them loose to photograph. Remember now having to get new, straight ones off eBay to replace the originals. Pic on here somewhere.. My old bar mixer. You can just see the copper pipe into the 1/2" side of yhd adapter. 1 Link to comment Share on other sites More sharing options...
8ball Posted June 1, 2019 Author Share Posted June 1, 2019 10 minutes ago, Onoff said: Bugger...have I given him a bum steer? Sorry @8ball! ? Link to comment Share on other sites More sharing options...
PeterW Posted June 2, 2019 Share Posted June 2, 2019 22 hours ago, 8ball said: Now that's what I'm talking about, Thanks PeterW. do these fittings have a washer or an olive in between them or is it just a bit of PTFE tape as you suggested Sorry - bit of PTFE and do it up F.T...... 1 Link to comment Share on other sites More sharing options...
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