I'm relocating my hot water cylinder in my bungalow to the loft near the cold water tank. I know that the CW tank needs to be at least 1 metre higher than the showerhead, but does it also need to be higher that the HW cylinder (or can they be positioned side by side)?
From the perspective of flow to the shower head it is the cold tank that is the defining thing.
However, there is a problem in that there needs to be some amount of vertical distance between the tank and the cylinder to accommodate the vent pipe, and in any case as a minimum the water level of the cold tank needs to be above that of the cylinder.
If there is not adequate vertical distance for the vent pipe, there will be a tendency for it to suck in air.
Therefore as a minimum you need to be able to come up with a way to support the cold tank solidly at a height above the cylinder once the latter is moved to the loft.
If you can't do that, you will need to use something based around mains water supply such as a thermal store.
Assuming that the cold water tank is a 'normal' vented tank fed off a 'ball valve' .... all of the cold-water mains pressure is 'lost' once the ball-valve closes. [that's why such systems are styled ;- 'vented'] The pressure of the water at the cold water tank's outlet will be one~two feet high. In other words the pressure (aka 'head') is merely that of the top water surface, The shower head needs to be at least one metre _below_ the upper surface of the cold water tank. {It's not easily achieved:if you place the tank of the bungalow's loft floor with the shower head perhaps one~two metres above the bungalow's floor, How high are your ceilings? If you place the hot water cylinder side-by-side - (do you mean standing on the same platform with their bases at the same level?) - then the hot-water cylinder will only fill to the level of the upper-surface of the cold water tank. Water doesn't 'fall' up-hill A moments reflection, perhaps drawing it out on paper, should indicate to you that the bottom of the cold water tank needs to be higher than the top-most part of the hot-water cylinder. [There should be a expansion pipe from the upper-most part of the Hot-water cylinder bent over to discharge into the cold water storage tank too ... have you thought of that?]
HTH,
Thanks Andy. I had planned to have the bottom of the CWT tank about
18" higher than the bottom of the HW cyl> >
That's really the minimum viable situation and gets you to the point that the cylinder will be full.
The other thing will be to put in a 28mm pipe to feed water from the CW tank to the cylinder. The effect of this will be that when you draw HW from the 22 or 15mm pipes from the cylinder, the flow rate can't exceed that between the CW tank and HW cylinder. If you don't have that then there is a fair chance that the level in the vent pipe will drop and air will be sucked in.
While you are doing this re-work you could look at running 22mm pipes (hot from cylinder and cold from tank) as close as you can to the shower. This may well improve flow.
The exercise as a whole won't improve pressure. That would need a mains HW system or a shower pump.
Don't forget that water is very heavy. If you are going to raise the CW tank and support the HW cylinder, there need to be substantial timbers and positioning over a load bearing wall. It is not something to put in the middle of an area on a few 75x50 joists.
Siphon?
Peter
Peter; your point is?
Water in a "siphon" does _not_ fall up-hill. Siphonic action only results in fluid from a pipe being discharged at a lower level (height aka head) than the source , The pipe may or may not take a path which 'goes' up hill (being pushed by the differential (air) pressure between the source and discharge points,,,, but the fluid will go only go 'down-hill'.
Perhaps you need to retake Siphons 101 along with Sarcasm 101.
It wasn't sarcastic, daft or maybe stupid I accept. I'm at home with flu and feeling woozy, and probably my brain wasn't in gear. Your message started me pondering about the possibility of water being siphoned out of one tank into the other if the connections were at different levels and I began to write you a message. But I couldn't work out what I was trying to ask so I cut most of the message and just left the one word as a question. No malice was intended but I'm sorry you were offended.
If you had a situation where the HWC inlet was higher than CWS tank outlet, water flowing into the HWC would look as though it was flowing uphill. I was trying to work out whether this could create a siphon, and whether the water would keep flowing after a tap is turned off .......
Madness. It's the relative water levels that count, not the connections. That's what I couldn't fathom last night. Doh! :o)
Peter
So what does raising the cold water tank do if not increasing head and pressure?
MBQ
On 31 Oct 2006 10:30:34 -0800 someone who may be "yogi" wrote this:-
How about replacing both of these with a packaged unit consisting of cylinder with tank above?
snip
Thanks. I freely admit I posted too quickly. My concern was that the OP might be confused - as the question as phrased inferred a lack of 'appreciation' of the fundamentals.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.