Hi There
This is my first post here and I'm hoping someone can give me some advice on the following problem I have and the 'fix' I'm thinking about. Appologies if it's a bit long winded but I want to explain what's happening and also the background.
Have just recently installed a 3 way theormostatic concealed valve to upstairs bathroom to operate bath filler, fixed shower head and side rail shower head.
Have fitted a Salamander RSP 75 in the airing cupboard located next to the HW Cylinder. CWS is located in loft above the HW Cylinder. Dedicated feeds to pump from CWS and an Essex flance from the HW cylinder.
Pump is located @ 12 feet below the CWS but the 2 shower heads are only located about 12-18 inches below which I believe is creating a borderline negative head situation.
The problem Im getting is when selecting either of the 2 shower heads on the valve, the pump does not kick in and there is no flow at all. If I switch to the bath filler (which is much lower than the shower heads and very much a posstive head) the pump kicks in straight away. Once the flow has statred I can then select either of the shower heads and all is well.
Inside the shower valve are 2 filters and 2 non return valves - one set of each on both the hot and cold feeds to the thermostatic cartridge.
The filters are not blocked and I concluded that the problem was as follows.
Due to the borderline negative head, in both the shower positions, there is just not sufficient pressure / flow to open the non return valves and kick the pump in. Incidently if when either shower head is selected and the water turned to on and there is no flow, by turning the thermostatic valve to either all hot or all cold, the pump then kicks in which I belive is further indiction that the negative head effect is very borderline as by switching the bias of flow to just one of the Non return valves, the flow/ pressure is sufficient to open it and kick the pump in.
So what I did was remove the 2 non return valves from the thermostatic valve and as suspected, all three outlets worked fine with the pump kicking in straight away with no problem.
However, what I did notice was a second or so of overrun on the RSP 75 once the water is turned off on the thermostatic valve which was not happening when the non return valves were in place.
So my question is will I be OK to remove both the non return valves, or should I leave one or both in. If I leave them out will there be any potential problems in terms of the pump overun and the fact that there is a potential open flow in the system (note that the HW Cylinder and the direct feeds to the pump are all fed from the same CWS and all in 22 pipework).
If its better to put one or two of the non return valves back in place and the problems re manifests, would the simplist solution be to then raise the hight of the CWS tank in the loft.
Hope above makes sense and would appreciate some guidance and thoughts please.
Rgds
Simon
This is my first post here and I'm hoping someone can give me some advice on the following problem I have and the 'fix' I'm thinking about. Appologies if it's a bit long winded but I want to explain what's happening and also the background.
Have just recently installed a 3 way theormostatic concealed valve to upstairs bathroom to operate bath filler, fixed shower head and side rail shower head.
Have fitted a Salamander RSP 75 in the airing cupboard located next to the HW Cylinder. CWS is located in loft above the HW Cylinder. Dedicated feeds to pump from CWS and an Essex flance from the HW cylinder.
Pump is located @ 12 feet below the CWS but the 2 shower heads are only located about 12-18 inches below which I believe is creating a borderline negative head situation.
The problem Im getting is when selecting either of the 2 shower heads on the valve, the pump does not kick in and there is no flow at all. If I switch to the bath filler (which is much lower than the shower heads and very much a posstive head) the pump kicks in straight away. Once the flow has statred I can then select either of the shower heads and all is well.
Inside the shower valve are 2 filters and 2 non return valves - one set of each on both the hot and cold feeds to the thermostatic cartridge.
The filters are not blocked and I concluded that the problem was as follows.
Due to the borderline negative head, in both the shower positions, there is just not sufficient pressure / flow to open the non return valves and kick the pump in. Incidently if when either shower head is selected and the water turned to on and there is no flow, by turning the thermostatic valve to either all hot or all cold, the pump then kicks in which I belive is further indiction that the negative head effect is very borderline as by switching the bias of flow to just one of the Non return valves, the flow/ pressure is sufficient to open it and kick the pump in.
So what I did was remove the 2 non return valves from the thermostatic valve and as suspected, all three outlets worked fine with the pump kicking in straight away with no problem.
However, what I did notice was a second or so of overrun on the RSP 75 once the water is turned off on the thermostatic valve which was not happening when the non return valves were in place.
So my question is will I be OK to remove both the non return valves, or should I leave one or both in. If I leave them out will there be any potential problems in terms of the pump overun and the fact that there is a potential open flow in the system (note that the HW Cylinder and the direct feeds to the pump are all fed from the same CWS and all in 22 pipework).
If its better to put one or two of the non return valves back in place and the problems re manifests, would the simplist solution be to then raise the hight of the CWS tank in the loft.
Hope above makes sense and would appreciate some guidance and thoughts please.
Rgds
Simon
