Hi, I'd really welcome advice on our shower problem. I'm reasonably competent DIY'er but i'm starting to struggle with the plumbing in our house.
We have removed the airing cupboard from our upstairs bathroom to be replaced with a shower cubicle. Unfortunately, the loft has limited height so with this in mind i have used a "coffin tank" for the CWS and a horizontal HWC.
To better illustrate our system is as shown below:
If that didn't work it's also here....
http://stanleyes.ndo.co.uk/layout2.jpg
Due to the small 1.3m head i got a Salamander RSP50 twin pump.
The problem is air being pulled down the vent pipe, i'm guessing due to the small height difference between the CWS and HWC. Note this occurs not only for the shower pump but also if the bath hot tap is run at full bore, (i.e. it splutters badly)
I realise this system is far from ideal but i'm wondering if there are any tweaks i can do which may make it workable.
Testing the system shows that if we try and draw too much hot water we start getting air. If i restrict the flow using the lever valves the issue improves. In fact, as far as the bath tap goes this would be an adequate work around. However, for the shower this is not quite sufficient. With the shower valves fully open we get a flow of 10L per minute. If i restrict this to 5L per minute the shower is good enough and the air issue is resolved. That is, until someone uses a hot tap elsewhere in the house.
I can see i need to seperate the shower feed from the vent pipe. I do have a Salamander S Flange (like a Surrey) but it won't fit into the HWC because the dip tube hits the coil of the HWC. The coil is directly in the middle of the hot water outlet and is far to rigid to allow the flange to be forced in. This is the reason i currently have the shower tee'd off the vent.
Possible Improvements:
1. There is a supplementery outlet on the end of the HWC which i'm told is sometimes used for showers. I wasn't keen on using it because it is halfway down the cylinder so i'd imagine the shower would soon run tepid. However, i'm wondering if i could effectively make my own flange with a bent tube to draw the water from nearer the top of the HWC (say 1" from top). To do this i think i need some kind of fitting to allow a pipe to pass through the fitting but still seal it to the tank outlet. Does such a fitting exist, if so what's it called?
2. I could replace the cold water feed between the CWS and HWC with 28mm pipe. It's currently in 22mm and has 5 90 degree elbows. Do you think this would allow the cold water replacement to keep up with the hot water draw and prevent the problem? I'm sure it would help but i don't have a feel for whether it would make a significant difference.
3. I could add an Essex flange to the tank for the shower. Can these be used on horizontal tanks? I'm guessing it would want to be slightly further round the tank (i.e. at 1 o'clock rather than 12 o'clock) to reduce the chances of air getting drawn in.
And finally, i do intend adding another identical CWS coupled to the first to increase our cold water capacity. However, i want to get an air free system before i shell out on another CWS.
many thanks
Stan[/img][/url]
We have removed the airing cupboard from our upstairs bathroom to be replaced with a shower cubicle. Unfortunately, the loft has limited height so with this in mind i have used a "coffin tank" for the CWS and a horizontal HWC.
To better illustrate our system is as shown below:
If that didn't work it's also here....
http://stanleyes.ndo.co.uk/layout2.jpg
Due to the small 1.3m head i got a Salamander RSP50 twin pump.
The problem is air being pulled down the vent pipe, i'm guessing due to the small height difference between the CWS and HWC. Note this occurs not only for the shower pump but also if the bath hot tap is run at full bore, (i.e. it splutters badly)
I realise this system is far from ideal but i'm wondering if there are any tweaks i can do which may make it workable.
Testing the system shows that if we try and draw too much hot water we start getting air. If i restrict the flow using the lever valves the issue improves. In fact, as far as the bath tap goes this would be an adequate work around. However, for the shower this is not quite sufficient. With the shower valves fully open we get a flow of 10L per minute. If i restrict this to 5L per minute the shower is good enough and the air issue is resolved. That is, until someone uses a hot tap elsewhere in the house.
I can see i need to seperate the shower feed from the vent pipe. I do have a Salamander S Flange (like a Surrey) but it won't fit into the HWC because the dip tube hits the coil of the HWC. The coil is directly in the middle of the hot water outlet and is far to rigid to allow the flange to be forced in. This is the reason i currently have the shower tee'd off the vent.
Possible Improvements:
1. There is a supplementery outlet on the end of the HWC which i'm told is sometimes used for showers. I wasn't keen on using it because it is halfway down the cylinder so i'd imagine the shower would soon run tepid. However, i'm wondering if i could effectively make my own flange with a bent tube to draw the water from nearer the top of the HWC (say 1" from top). To do this i think i need some kind of fitting to allow a pipe to pass through the fitting but still seal it to the tank outlet. Does such a fitting exist, if so what's it called?
2. I could replace the cold water feed between the CWS and HWC with 28mm pipe. It's currently in 22mm and has 5 90 degree elbows. Do you think this would allow the cold water replacement to keep up with the hot water draw and prevent the problem? I'm sure it would help but i don't have a feel for whether it would make a significant difference.
3. I could add an Essex flange to the tank for the shower. Can these be used on horizontal tanks? I'm guessing it would want to be slightly further round the tank (i.e. at 1 o'clock rather than 12 o'clock) to reduce the chances of air getting drawn in.
And finally, i do intend adding another identical CWS coupled to the first to increase our cold water capacity. However, i want to get an air free system before i shell out on another CWS.
many thanks
Stan[/img][/url]
