many pressurised system questions

thetourist

we are building a house and will have a fully pressurised system which is where there are no tanks in the attic at all - everything ( hot and cold ) gets fed from the cylinder ( which has a system for cold/drinking water built in ) -- apparantly you can run the system directly from the mains water supply ( we will be on a group scheme ) - but it's preferable to have a 300gal storage tank outside and a pump so you can keep control over the sysem, that way if the local farmer decides to power hose the farmyard it wont affect the pressure in your shower

does anyone have any experience of all this -- i have a lot of questions and i want to get it right. Is the storage tank really necessary. Surely if there is enough pressure in the mains to supply the whole group then there wont be large enough fluctionation in it to affect things

another thing is that our builder, though not a plumber by trade seems to think that even if there is a regular supply entering the house the mains supply would fall off if there were a number of outlets used at the same time. i want to avoid this if possible as one of the major attractions with the pressurised system is that i'm not supposed to need thermostatic mixer valves on the showers as the pressure remains constant.

is the bulder right -- i'm beginning to think that a pressurised sytem necessitates 2 aspects ( 1 - a pressurised cylinder and ... 2 - a pump( and storage tank ) to keep the water under pressure

though maybe the mains pressure is good enough - i have come to the conclusion that the issue of one of maximum flow rate rather than pressure
the water scheme is a new one .. not even fully built yet - so it's up to current standards .. but how can i check what flow rates/ pressures i need

also i'd love to know if i instaled a suitable pump at the gable end of the house would it be noisy, say if the WC was leaking in the middle of the night and it caused the pump to start.
any ideas about how much i'd need to spend on a tank and pump

also i'm aware that the drinking water would be coming through this tank and that it would be necessary to have a vent on the tank to prevent the tank colapsing under atmospheric pressure -- is there a standard method of preventing dust, insects etc from entering the tank through the vent?

if anyone has any opinions or experience with this id greatly appreciate any help
thanks a million !!!

hopefully this is in the most appropriate forum

boards.ie rocks !!!

tapest

Hi BOB
I'm not a plumber, but i'm well up on Systems . Fully pressurised system for central heating...yeh ok no problem here and its a little cheaper to run. system uses a small sealed metal container witha "bladder" inside and , believe it or not, you can increase pressure between bladder and container with a bicycle pump.
But I have never heard of the domestic supply (which must be seperate) not having a storage capacity of some sort, typically 50/60 gls.
Anyway for the definitive answer contact "Eolas" used to be called IIRS, and they used to be in Glasnevin, near Mobhi Road. For a few quid you can buy the "standard"-- a book/booklet containing all rules and building regs etc
hope this helps
ap

Victor

Originally posted by bobmurphy
we are building a house and will have a fully pressurised system which is where there are no tanks in the attic at all - everything ( hot and cold ) gets fed from the cylinder ( which has a system for cold/drinking water built in )

Does it actually have a water filter for a "third tap"?

Originally posted by bobmurphy
Is the storage tank really necessary.

Yes, what would you do if there was a burst main or the pump for the group scheme was shut down for maintenance?

Originally posted by bobmurphy
Surely if there is enough pressure in the mains to supply the whole group then there wont be large enough fluctionation in it to affect things

No, your wrong.

Originally posted by bobmurphy
another thing is that our builder, though not a plumber by trade seems to think that even if there is a regular supply entering the house the mains supply would fall off if there were a number of outlets used at the same time. i want to avoid this if possible as one of the major attractions with the pressurised system is that i'm not supposed to need thermostatic mixer valves on the showers as the pressure remains constant.

Go with what the builder and his plumber recommend. You will still need the thermostatic mixer - you just are unlikely to need a shower pump.

Originally posted by bobmurphy
though maybe the mains pressure is good enough - i have come to the conclusion that the issue of one of maximum flow rate rather than pressure
the water scheme is a new one .. not even fully built yet - so it's up to current standards .. but how can i check what flow rates/ pressures i need

As you are on a group scheme, not an individual pump or town scheme, pressure is likely to be fickle, depending on the way all the users draw supplies - if there are a bunch of dairy farmers all drawing a lot of water at the same time you want a shower, the pressure just won't be there. The group scheme is designed with the idea of you having some storage yourself - it is not designed to supply the absolute peak demand by itself (without storage) as the cost would be prohibitive.

Originally posted by bobmurphy
also i'd love to know if i instaled a suitable pump at the gable end of the house would it be noisy, say if the WC was leaking in the middle of the night and it caused the pump to start.

Then fix the WC! If the pump is in the boiler room your shouldn't really here it. Also it would only cut in intermittently, so it wouldn’t be running all night.

Originally posted by bobmurphy
any ideas about how much i'd need to spend on a tank and pump

Surely this is already included in the price of the house? I imagine a few hundred euro.

Originally posted by bobmurphy
is there a standard method of preventing dust, insects etc from entering the tank through the vent?

Yes a simple air filter.

No, offence, but to be honest you are coming across as someone trying to skimp without knowing the effects of skimping and are trying to "reinvent the wheel" and trying to tell the builder / plumber his job.

pipers

i agree with victor, bobmurphys queries were answered in detail on this forum recently (he also posted on a uk plumbing site.)

thetourist

No, offence, but to be honest you are coming across as someone trying to skimp without knowing the effects of skimping and are trying to "reinvent the wheel" and trying to tell the builder / plumber his job.

not at all -- the last thing i want to do is skimp -- i am spending an extra 10G on a ground source heat pump and also the extra on a pressurised system -- do you not think that if i had any intention of skimping the first thing i'd do would be to put in a regular system -- i have every intention of putting in a great system - i just am not an expert on plumbing - also neither is my builder, who is an excellent builder btw, but he has not put in a fully pressurised system before -- also we are not using "his plumber" -- so im not telling anyone how to do their job -- i simply want to know what the best system to put in would be before i get a plumber to tender for it

i can tell you this though -- notwithstanding the fact that you gave me some good advice in your post --- i could tell as i read throught it even before i came to that last bit that you seem impatient and judgemental -- and without all the facts -- so please dont be so quick to judge

Victor

Sorry, bitter memories of clients

thetourist

i agree with victor, bobmurphys queries were answered in detail on this forum recently (he also posted on a uk plumbing site.)

im sorry but i dont recall ever getting any information about this on this forum -- if im wrong then sorry -- and sorry for wasting precious
forum space -- i didnt know that you were paying for it !!!

as far as the post i made on the uk site - i dont think that i asked or found out anything about this question ( ie the pump/ tank)

my god -- ! im only asking a couple of simple questions -- you'd swear it mattered or something !!!

thetourist

Sorry, bitter memories of clients

no worries