pumped hot water

[jamesboy678]

young lad just qualified as plumber and have been asked by a mate to sort his hot water out.

he lives in a single flat no upstairs and has a gravity fed system. the hot water is indirect fed and feeds one basin tap, one kitchen tap, mixer shower and bath tap. the flow rate is extremely poor due to the head pressure being ridiculously low. he has asked me if i can install a pump to help out with the hot water. has anyone got advice on how i would go about deciding what pump to use and how i would go about the job?

any advice much appreciated

 

[charlie frederi]

young lad just qualified as plumber and have been asked by a mate to sort his hot water out.

he lives in a single flat no upstairs and has a gravity fed system. the hot water is indirect fed and feeds one basin tap, one kitchen tap, mixer shower and bath tap. the flow rate is extremely poor due to the head pressure being ridiculously low. he has asked me if i can install a pump to help out with the hot water. has anyone got advice on how i would go about deciding what pump to use and how i would go about the job?

any advice much appreciated

Hi
I would fit a stuart turner negative head pump single impella for the hot and put the
cold on the mains

 

[jamesboy678]

thanks very much for the reply, i will look into that. also im i right in thinking that the pump should be placed after the vent pipe to avoid pumping over the vent?

 

[moony]

thanks very much for the reply, i will look into that. also im i right in thinking that the pump should be placed after the vent pipe to avoid pumping over the vent?

i would personally come straight out of cyclinder using an essex flange.

also i would think twice about using a pump on the hot and mains pressure.... i would personally pump both the hot and the cold from the cylinder and cwsc respectively to ensure equal pressures.

 

[jamesboy678]

the flat is very small as well, and my mate aint short of a few bob. he has been complaing about the state of the flat for long time and i was thinking would it be an option to maybe install a unvented system in the flat? that way the cold and hot are balanced. i have my unvented hot water ticket so installing it would be ok for me to do

 

[moony]

go for it mate. expensive bit of kit though.crazy how you need to know how to fit a pump but you can fit unvented crazy how these qualifications work.

 

[newbie1]

listen out for a unvented cylinder going into orbit soon

 

[secret squirrel]

If your fitting your unvented cylinder, I'd re-read all your books, read the install guides twice, have a look at the property twice (at least) you'll see things you missed the first time, if you think it'll take a day it'll take 2. Think about where all the pipe works going, re-check everything before commissioning, have the cylinder help line programmed in your mobile just in case. Maybe being over cautious but this is what I do. Good luck.

 

[charlie frederi]

i would personally come straight out of cyclinder using an essex flange.

also i would think twice about using a pump on the hot and mains pressure.... i would personally pump both the hot and the cold from the cylinder and cwsc respectively to ensure equal pressures.

Hi

that is right about the essex flange and i agree about putting both feeds on the one pump that is providing the ballvalve can keep up with it
have done that in similar situations and the ballvalve could not cope
so had to use pump for the hot and blank the cold on tank joining to the mains which works perfectly well and has for the last five years.
also depends on mains pressure as most likley between 1 & 2 bar
which i am pretty sure a pump runs at

cheers

 

[moony]

well some of these showers fitted can be expensive and a thermostatic head being about 60-70 quid plus labour - i would prefer to make sure the hot and cold were equal pressures... have never fitted mains onto a pump before as it can invalidate the warranty on the pump too if not fitted to manufacturers instructions - im not saying it wouldnt work charles me old mate - but its not something i would do myself.

 

[charlie frederi]

well some of these showers fitted can be expensive and a thermostatic head being about 60-70 quid plus labour - i would prefer to make sure the hot and cold were equal pressures... have never fitted mains onto a pump before as it can invalidate the warranty on the pump too if not fitted to manufacturers instructions - im not saying it wouldnt work charles me old mate - but its not something i would do myself.

HI mate
Think may u have miss understood i would never fit mains to a pump unless it was a booster pump on a high rise building.
i simply stated using a single impella neg head pump on the hot and changing the cold supply to the bathroom to mains pressure

 

[moony]

would that then make the both pressures equal though ?

 

[charlie frederi]

would that then make the both pressures equal though ?

Depends what the mains pressure is
if you are talking about a shower you can use pressure reducing valves.

Or there is a shower on the market that has mains feed and hot feed with no pump trevi boost and a shower is the only place you would want equal pressure?

 

[moony]

yeah i know of the trevi never come across one though.

yeah thats all i was asking charlie, a prv would have to be used, therefore i would personally use a pump on the cwsc for cold and hot cylinder no need for the prv then. But i see what system you would use - charlie im only on my level 3 myself in heat and vent so look for different ways of doing things and all views are welcome - more i know the better.

cheers

 

[still learning]

what ever pump you may choose just be sure the cold water tank feeder is big enough to not get sucked dry by pump, also, use proper flange on top of cylinder to save sucking in air, hope this helps omigo

 

[charlie frederi]

yeah i know of the trevi never come across one though.

yeah thats all i was asking charlie, a prv would have to be used, therefore i would personally use a pump on the cwsc for cold and hot cylinder no need for the prv then. But i see what system you would use - charlie im only on my level 3 myself in heat and vent so look for different ways of doing things and all views are welcome - more i know the better.

cheers

Why would you fit a pressure relief valve on the mains water supply
as the mans would have nothing to do with the cylinder.
you would use a PRV on unvented system yes

I would also prefer to use a pump for both feeds but as you go on in later work you will find this is not always possible as some times you might come across scenarios where the CWST may be to small to cope or the flow to the ballvalve is poor
cheers

what ever pump you may choose just be sure the cold water tank feeder is big enough to not get sucked dry by pump, also, use proper flange on top of cylinder to save sucking in air, hope this helps omigo

Spot on m8

 

[jamesboy678]

thanks for all the replies. i forgot to mention i wouldn't be doing the unvented hot water cylinder alone if he wanted it done! i was going to do the pump on my own but if he wanted unvneted hot water, i was going to get a guy at my plumbing work to come and help me.

 

[still learning]

unvented systems are pretty straight forward providing you follow the basic layout of valves and expansion vessel location, just follow the diagram you got from school... looks more complicated on paper than it really is.

 

[moony]

Depends what the mains pressure is
if you are talking about a shower you can use pressure reducing valves.

Or there is a shower on the market that has mains feed and hot feed with no pump trevi boost and a shower is the only place you would want equal pressure?

Why would you fit a pressure relief valve on the mains water supply
as the mans would have nothing to do with the cylinder.
you would use a PRV on unvented system yes

I would also prefer to use a pump for both feeds but as you go on in later work you will find this is not always possible as some times you might come across scenarios where the CWST may be to small to cope or the flow to the ballvalve is poor
cheers



Spot on m8

you mentioned prv matey

i was merely stating that it would have to be used.

theres mains around here that are 7 bar.... so to protect the thermostatic head a prv would haver to be fitted to equal the pressure from the pump 1-2 bar.

doesnt matter anyways, if someone had a small cwsc i would advise to either enlarge to have enough for a power shower or go electric.

 

[charlie frederi]

you mentioned prv matey

i was merely stating that it would have to be used.

theres mains around here that are 7 bar.... so to protect the thermostatic head a prv would haver to be fitted to equal the pressure from the pump 1-2 bar.

doesnt matter anyways, if someone had a small cwsc i would advise to either enlarge to have enough for a power shower or go electric.

yeah i did mention the prv you wouldnt need one as the pressure reducing valve would protect the shower
that is high 7 bar i suspect most people have pressure reducing valves
fitted
is there a PRV that can handle 7 bar for domestic use highest ive seen is 6 on commercial mains water unvented systems

 

[Earnest Lee]

Hi guys.
New to the forum. - Wondered if I could jump in on this one?
I've been scouring other sites to get a definitive answer for the same questions 'Newbie' was asking.
My system is pretty conventional. - Gravity H/W(vented cylinder), Pumped Heating controlled by 'Y' plan (single Mid-valve)
After just fitting kitchen mixer taps - mistakenly high-pressure units!!!! - thought it may well be a good idea to fit a pump to whole H/W system. (H/W pressure in bathroom is adequate)
Have read endless posts (and arguments!) about associated problems with overflowing vent pipes, fitting check valves, NOT fitting check valves etc. etc......
Just wonderin if it is 'do-able' or best to just forget it all and re-fit some low pressure taps to kitchen? - Only thing swaying me to persevere with it was the fact that I intend to fit a whole house water softener at some future point.

Any help will be most appreciated. Thanx.

 

[Howsie]

New taps. Simple and cheaper by far.

 

[p the plumber]

Hi there, Esssex Flange would work with negative Stuart Turner pump but sounds like a better install would be a nice smallish unvented cylinder with unvented pressure vessel and D1 D2 pipework correctly sized. This will give quieter noise levels when showering as pumps can be noisy and your mate can afford a decent system as you say. Good luck

 

[Howsie]

Hi there, Esssex Flange would work with negative Stuart Turner pump but sounds like a better install would be a nice smallish unvented cylinder with unvented pressure vessel and D1 D2 pipework correctly sized. This will give quieter noise levels when showering as pumps can be noisy and your mate can afford a decent system as you say. Good luck

Counting to ten.

 

[Dotty]

I'd change the taps instead.