water pressure boosting?

bobster2543

Hi can anyone help, I have a unvented system we have very poor mains pressure so a gundfus mq3.5 booster pump was fitted to the gravity feed form storage tanks to boost the hot and cold taps /shower , the pump has been acting up turning off and on and sometimes stopping completely half way through a shower! , i never liked the pump anyway it was to loud , so i have removed it from the system and now feeding the cylinder directly from the gravity from the storage tanks in the attic, the pressure from this is about .75 bar which is fine for down stairs but not upstairs where we now cant use the shower , my question is can i fit a Grundfos UPA 15/90 Home Booster Pump with flow switch in replace of the grundfus mq 3.5 which will boost the gravity feed into the cylinder therefore boosting the hot and cold at the same time ? or does it have to connected to the hot after leaving the top of the cylinder as i only need an extra 0.5- 1 bar pressure where can i fit this pump and will it work.
Thanks Bob

spireland32

Upa is for open/vented systems as far as I remember

bobster2543

would there be a problem in fitting this to replace the mq3.5 , it pumps water as before and has a flow switch , or am i missing something .

spireland32

Steve your posts are huge and make no sense. Did you not read the original post. He has a unvented plumbing system, so the whole house is pumped. He doesnt say anything any his bathroom on mains.

OP you need a similar pump to the MQ, wilo and walrus are other brands. Be grundfos would be the best

bobster2543

hi thanks for response guys the pump that was fitted to a single feed of the storage tank this boosted the cold from storage which splits before entering the cylinder , the feed then continues into the bottom of the cylinder which boosted the hot also , so now i have removed it and just want to fit the upa 15/90 into the same single cold feed from the storage tank. before any run offs to cold and cylinder which will boost all the taps and hot a (that is what the mq 3.5 pump done) so think this upa pump should do the same thing only at a lower pressure
is this right?
link to mq pump http://www.pure-aqua.com/mq-booster-pumps.html

shane0007

Irish Steve wrote: »

Google may well be your friend here

IrishSteve, unvented cylinders can be dangerous things when not installed correctly or by people who do not understand them. Trawling google to give ill advice on forums is not what I would call friendly but dangerous.
Unvented cylinders is a certified associated plumbing module that requires care, duty & particular attention. If you are not certified in this, you should really refrain from advising on this topic as it could potentially lead to somebody getting seriously hurt or worse, killed.

shane0007

bobster2543 wrote: »

hi thanks for response guys the pump that was fitted to a single feed of the storage tank this boosted the cold from storage which splits before entering the cylinder , the feed then continues into the bottom of the cylinder which boosted the hot also , so now i have removed it and just want to fit the upa 15/90 into the same single cold feed from the storage tank. before any run offs to cold and cylinder which will boost all the taps and hot a (that is what the mq 3.5 pump done) so think this upa pump should do the same thing only at a lower pressure
is this right?
link to mq pump http://www.pure-aqua.com/mq-booster-pumps.html

Yes it will but enormously lower pressure. You will find that if a number of taps are opened at the same time, such as mixers, etc. you will find it behave very poor. The difference being flow rate & pressure. If you calculate the head height from the tap to the level of water in your tank, 0.1 bar pressure for every meter of head, so upstairs would be approx 2.0 which would be 0.2 bar pressure. Add the range of the 15/90 which is 0.5 - 0.75 so that would be a total pressure of 0.7 - 0.95 bar. This would be ok on a single tap for pretty miserable if shared pressure with mixers, baths, other taps, etc.
Compared to a typical 3 or 4 bar pump, there really is no comparison.

bobster2543

Thanks Shane , i have at the moment 0.6/0.7 bar from the gravity its fine for downstairs even when a few taps are on , only upstairs is poor so boosting it by 0.5 /1 bar i reckon would be enough , when the old grundfus pump was in the gauge was reading 2/3bar pressure which was to high a pressure and that was with a pressure reducing valve fitted also the noise was hell .

spireland32

It may work but its not really its designed use. The pressure will be significantly different to your mq. As I said before its for open systems or pumping mains (on authorization from local council)

Irish Steve

shane0007 wrote: »

IrishSteve, unvented cylinders can be dangerous things when not installed correctly or by people who do not understand them. Trawling google to give ill advice on forums is not what I would call friendly but dangerous.
Unvented cylinders is a certified associated plumbing module that requires care, duty & particular attention. If you are not certified in this, you should really refrain from advising on this topic as it could potentially lead to somebody getting seriously hurt or worse, killed.

My bad, I misread part of the original post, so I've pulled the earlier post

Sorry for any confusion