MegaSack DRAW - This year's winner is user - rgwb
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Am in the process of redoing a bathroom. Have ripped out everything including electric shower with intention of fitting a more powerful shower from my hot water system. Unfortunately the hot water pressure upstairs is rubbish so decided to fit a pump to provide more pressure to the system. Ordered and fitted a grundfos pump below my hot water cylinder. Cut pipe coming out of the cylinder and took pipes down to the pump and then back to rejoin the other end of the cut pipe ie rejoining the hot water pipe network. Got all the air out of the system and started it up and it worked a treat. Unfortunately the never stopped working even though all the hot water taps were closed. Kept trying to sort it out refitting etc. Eventually called grundfos who reckoned it must be faulty and sent me a replacement. Fitted it and same problem. Asked my plumber what was wrong and he said that the pump was pumping hot water up to my header tank as this is an open vent. He has suggested cutting the vent pipe and then bringing a pipe back to rejoin the hot water cyclinder. This is not easy as there is no easy pathway. We are talking major disruption to floors etc.
Any ideas? Do I give up on the pump and go back to electric? What about the showerpowerbooster.co.uk in line with the shower. Anybody know anything about them.
Help!
Think you need to plumb the pump to feed the shower only
Then the pressure switch will shut it off when you turn off the shower
Bear will know, but think your plumbers idea isnt the best practice, your hw system is vented for a reason
Salamander and stuart turner do pumps for around 100 quid that wpuld sufficient for a shower
Yes you can’t just connect a pump in line with the hot as it is an open vented system. Also showers generally have balanced pressures, not sure where you are getting the cold from.
I would probably suggest the easiest solution is a digital mixer, however you need to connect the supplies into it correctly to avoid drawing air into the pump.
Alternatively consider changing to an invented cylinder as it will be a whole house solution, less noisy than a pump too.
And lastly neither you or your plumber seem to have much technical understanding, so I would suggest finding another plumber and probably reading the instructions for the pump as it will have diagrams of how to fit it. Please don’t take that the wrong way but if a plumber doesn’t understand why that was happening and the purposes of the open vent from a cylinder then I would be concerned.
Invented system every time - way better than a pump.
Megaflo cylinders come up on eBay all the time.
I bought a used cylinder to replace a vented tank and pump in our other place 7 years ago and it's been perfect.
In theory all you'd need is to insert a flow switch on the HW pipe to the shower and run the pump power cable through this. But as above, and without wanting to come across as mean, it doesn't sound like either you or your plumber are best placed to sort this out: his suggestion of bypassing the header tank is downright dangerous - you'd basically be turning your hot water system into a bomb. I wouldn't be trusting him anywhere near your heating system.
Have you fitted a 'Surrey Flange', pretty much the first thing to do if you are fitting a shower pump. it stops the pump from constantly pulling air from the top of the cylinder.
To be honest it's the first thing the plumber should have checked.
took pipes down to the pump and then back to rejoin the other end of the cut pipe ie rejoining the hot water pipe network
IANAP and I don't understand this bit - why take hot back to the cylinder? Doesn't it just go Cylinder->pump->mixer->showerhead then to waste?
No, he meant that the pump outlet it was connected to the existing pipework {heading to the shower} - so the pump was inserted between the cylinder and the existing pipework.