boosting my pressure

[mrrigidtool]

can anyone see a problem with this set up, got a unvented direct cylinder 250l fitted with a balancing valve set at 3bar to supply hot to cylinder and cold to house, was going to set pressure switch to come on when there is a large pressure drop hence fitting reducing valves to basin and sink to stop pump kicking in all the time. Have a pump rated at 60ltm will want priority to new wet room with body jets. Cwsc already in as converting from gravity fed and my central heating is hook up on a completly separate rig. though if i use the two 22mm pipes that come down from loft i.e the old hot and cold t into a 28mm pipe to feed pump and then feed back out of the balancing valve for cold straight back into the old cold supply which is 22mm and convienient in airing cupbard, and the same for the hot.

appreciate any thoughts, new to this site and i'm traing at current for my A.C.S gas course.

image of set up
//www.diynot.com/network/mrrigidtool/albums/

Untitled

• mrrigidtool
• 26 Aug 2008
• 1

 

[Agile]

Is this "CWSC" something that you have built yourself?

Just because a pump is rated at 60 li/min it does not mean that it will provide a very high flow into an output pressure of say 1.5 Bar.

How often the pump is triggered will depend on the size of the accumulator ( cue Simon D ). Better to have a higher pressure and a larger accumulator!

Tony

 

[ChrisR]

Normally you'd use a "negative head" pump - which is a pump with a flow switch and a small accumulator, which overcomes most of the problems.
It's still common to time the pump off at night so a dripping loo etc doesn't bring it on.

 

[mrrigidtool]

the cwsc is the original one used in the gravity fed sytem and is already there, the pump is a calpeda mxhn 204 it claims to do 60lt at 40m head http://www.calpeda-pumps.co.uk/mxh.pdf if i fit an accumilator would it be a benifit unless it was big enough to substain the shower need, i understand the principle behind it only no experiance with them, not to bothered about pump coming on if using sink as it will be in the internal garage for noise, at present using a shower pump on gravity fed system which worked well until boiler broke down old king fisher got a range 250l direct spare from a job and pump was accuried cheap, so not essential if not used, saw booster pumps at machine mart with there own 2ltr tanks nt used them before 2ltr seems quit small, if there is a better pump system ypu recommend reasonably priced then i'll gladly look at it,

 

[ChrisR]

if i fit an accumilator would it be a benifit unless it was big enough to substain the shower need

yes - look up how negative head pumps work!

 

[mrrigidtool]

thanks for the reply regarding negative head, does this still apply even if my pump is below the cwsc as it will have a head of 6m

 

[ChrisR]

YES!

 

[mrrigidtool]

thanks where is the best place to fit the accumilator and average size for this set up or shall i purchase a pump fropm machine mart with the 2lt tank.

 

[mrrigidtool]

can i getaway with the pump i have if i position it on the floor next to cylinder then it will be pushing upwards rather then a negative head pump. if not then i'll replace pump.

 

[Norcon]

Would one of these not work ?.
http://www.pumpexpress.co.uk/acatalog/Ekopress.pdf

Just a suggestion.
Don't see the need to change the pump. I have a local supplier who builds pump sets /pumping systems and he uses quite a few of these on his systems.
They do a larger one also rated for single phase pumps up to 2.2 kW.

 

[mrrigidtool]

thanks for link had the machine mart one in mind but this looks better and if its been used in systems thst you know of then i'll go for that.

 

[mrrigidtool]

thanks for link had the machine mart one in mind but this looks better and if its been used in systems thst you know of then i'll go for that.

 

[Technotim]

Wow ! I think that system is slightly over designed.

Why use pressure reducing valves where flow restrictor's will do ?

Do you intend to ditch the Cold water storage as 2bar mains is not ideal?

You had better store a lot of water unless your shower is fairly flow restrictive.

When you turn on the system do the street lights dim.

 

[mrrigidtool]

its 2bar on a guage in front garden tap flow is 8ltm the mains 15mm, tried it temporay with hep running to bathroom, terrible pressure, been using the same cwsc for two years before boiler packed in with a 2.4 bar shower pump gave a good shower but now adding body jets as well, not had any trouble with tank running dry at this level, if so maybe doubling the capacity will help. dont think 3bar is over the top with a ceiling head and jets in a wet room.

 

[mrrigidtool]

thought i'd use pressure adjustable reducing valves as you can set them easier to 1bar in order not to trigger the pressure switch on the pump however if you think flow restrictors would be better then i'll consider it thanks,