I need to replace a bottom-entry fill valve but there are a few things I'm not sure about.
Firstly... the existing (original) valve is a Roca one, and I'm having trouble identifying exactly which part it is because there seem to be at least a couple of different variants out there that look very similar. However, is there any need to replace it with a Roca one or am I better going for a generic brand such as Fluidmaster or Torbeck (ideally with a brass shank rather than the plastic one on the Roca)? I'm guessing that should be fine as long as I check measurements and adjust it as required.
Secondly, there seem to be at least a couple of different shank sizes available, the most common being described as 1/2". I hope this isn't a daft question, but what is this actually a measurement of? The inner diameter of the shank, or the outer diameter (including thread), or something else? Reason for asking is that the existing one doesn't seem to measure 1/2" anywhere obvious. The inner diameter is 1.5cm (= some obscure number in inches, perhaps because it's from a European manufacturer?). I've seen 3/8" European models mentioned online but that would be just under a centimetre which seems very small and also doesn't seem to correspond to the existing part, unless I'm measuring the wrong thing.
Finally, I noticed when removing the existing valve that it had been sealed into place using something that I presume to be normal sanitary silicone - it was between the rubber gasket where it meets the inlet in the base of the cistern, and all the way through that inlet hole filling in the space between the shank and the ceramic (which would otherwise have had maybe a 1-2mm gap around the circumference of the shank, although maybe that's not a problem as long as the gasket does its job properly). However, I've never seen instructions advising the use of silicone when fitting a fill valve, so I'm not sure if it's necessary or even advisable, or whether it's down to a size mismatch or just someone taking the initiative. I had thought about using a bit of plumber's putty around the thread when reconnecting it to the inlet, but apart from that I hadn't anticipated needing to use sealant.
Thoughts or advice on any of these points would be welcome - thanks in advance.
Firstly... the existing (original) valve is a Roca one, and I'm having trouble identifying exactly which part it is because there seem to be at least a couple of different variants out there that look very similar. However, is there any need to replace it with a Roca one or am I better going for a generic brand such as Fluidmaster or Torbeck (ideally with a brass shank rather than the plastic one on the Roca)? I'm guessing that should be fine as long as I check measurements and adjust it as required.
Secondly, there seem to be at least a couple of different shank sizes available, the most common being described as 1/2". I hope this isn't a daft question, but what is this actually a measurement of? The inner diameter of the shank, or the outer diameter (including thread), or something else? Reason for asking is that the existing one doesn't seem to measure 1/2" anywhere obvious. The inner diameter is 1.5cm (= some obscure number in inches, perhaps because it's from a European manufacturer?). I've seen 3/8" European models mentioned online but that would be just under a centimetre which seems very small and also doesn't seem to correspond to the existing part, unless I'm measuring the wrong thing.
Finally, I noticed when removing the existing valve that it had been sealed into place using something that I presume to be normal sanitary silicone - it was between the rubber gasket where it meets the inlet in the base of the cistern, and all the way through that inlet hole filling in the space between the shank and the ceramic (which would otherwise have had maybe a 1-2mm gap around the circumference of the shank, although maybe that's not a problem as long as the gasket does its job properly). However, I've never seen instructions advising the use of silicone when fitting a fill valve, so I'm not sure if it's necessary or even advisable, or whether it's down to a size mismatch or just someone taking the initiative. I had thought about using a bit of plumber's putty around the thread when reconnecting it to the inlet, but apart from that I hadn't anticipated needing to use sealant.
Thoughts or advice on any of these points would be welcome - thanks in advance.
). Or there's the Torbeck Ecofil (only 1 yr guarantee but supposedly water-saving... not sure how that works!). Both seem a reasonable price and fairly compact so hopefully no problems fitting my compact cistern.