Yes, 50 Gal CWSC, should be plenty.
Thanks
It's not about 'getting away' with it. All they need to do is check the dynamic pressure and flow (2 simple tests), that'll tell them if the mains is suitable or if it needs an upgrade. Price, I guess, isn't too bad and that would future proof the system. That would be an economy of scale decision for you though.
OK, they didn't suggest tests (I wish I knew to ask for it back then) but was put off somewhat by the cost and more so by the fact we can't seem to get anyone reputable to give firm timeline for availability. So I made the decision to go ahead with keeping gravity fed and DIY it. Now that I'm into it I'm actually enjoying it and learning loads. Which is a big thank you to you and all the great people on this forum. Thank you all.
Good news is I made good progress recessing the shower valves and getting the pipework done and surfaced up into the loft:
looking forward to pressure testing them and making sure all the joints are done properly!
Standard pumps installed into the 'dead space' isn't recommended, it can cause all sorts of issues further down the line.
Universal (negative head) pumps don't suffer so much but even then they have a least preferred space.
Both of these can especially have issues if the CWSC in the attic isn't raised at least 300mm above the attic floor level.
OK and I have also now discovered that the HW 22mm pipe I found that I was looking to use tees off the HWC vent in the loft, exactly as
@MeldrewsMate also suggested as a thing that shouldn't be done.
So now back to doing things properly and running two pairs of pipe across the loft properly.
For the pair of pipes that should be pumped for the shower I will listen to the advice, situate the pump in the airing cupboard and as low as possible.
Here is a photo of the space with some labeling:
(
@Madrab you actually answered a forum question a couple of years ago which helped me understand the pipework here!)
Looking at the top of the cylinder and cross referencing with v good advice I have received so far, it does not look like I have a s flange fitting. So I need to install one and do the associated work to separate the vent from the feed.
Pump shown in the photo feeds the main bathroom today and the intention is to keep it in place.
Yellow arrow is the only space I can fit a new pump for the new bathroom. I will need to re-route some of the pipes to neaten the area up.
The hot water supply from round the back of the HW cylinder on the left into the existing main bathroom pump is 15mm (used a wide angle shot which is making things look a little disproportional). If it were 22mm I would consider to tee off here into the 2nd pump but I think that could be an issue with HW capacity if both showers are used? So the alternative is to tee off where I have marked the red dashed box.
For the gravity cold water supply I would tee off the blue dashed box area, the main bathroom pump has a tee here already which is a reducing tee 22mm top 22mm bottom 15mm side. I would do another for the 2nd pump. I'll try to do it in the neatest possible way. It's all spaghetti junction anyway but will try not to make it too much worse.
As always any advice would be appreciated.
