Gravity hot water system - replace or improvement ideas please advise

[Sup9]

Hello all,

I currently have a gravity hot water system - with a 110x60x60cm water tank and a small one (expansion vessel?) in the loft, the water pressure in the bathrooms (3 on first floor) are very poor, especially the master bedroom en-suite (the furthest way from the cold water tank) which is unusable for shower. My understanding is that the cold water tank is feeding both the hot water cylinder and the cold water taps in all bathrooms. And I have tested at the ground floor tap, the mains water is 22L/mins so not so bad at all.

I also had a look in the loft and find out the cold water tank is the old style open tank with plastic sheet covers on top, which already fall off into the tank so the tank is quite dirty and I can see the built up limescale at the bottom.

So apart from the shower pressure I have the concerns about the water quality.

My understanding is that I have two options:

1. Keep the existing system with the loft cold water tank. Add multiple small pumps for each bathroom, and change the cold water tank to poly water tank with lid. This system is the safest system as the tank and cylinder is not pressurized, but the water quality could be getting worse along the time when the limescale built up and dust etc get into the tank.

For this setup my main concerns are Water quality over time and pump noise. Do people just get the tank professionally cleaned regularly? Or can I by pass the cold water tank and split the mains water (currently feeding the cold water tank) then connect all bathroom cold water pipes to it, so my bathroom cold water taps are feed directly by mains water - fresh and at the mains pressure. Then adding pumps for each bathrooms' hot water to balance off the pressure.

2. Convert to unvented cylinder, so the cold water will be at mains supply pressure. With 22L/min flow rate tested at ground level tap, am I guaranteed to have good shower performance in all bathrooms ( assuming only one in use or 2 showers simultaneously). And we are also slightly worried about the safety of the cylinder as it may blow up if not fitted right - I was not aware it could explode and cause serious damage, the cylinder fitting guy came for a quote and asked me to check out the explosion video - he was trying to make a selling point as he's manufacture approved installer and I am seriously put off by the possibility of it exploding.

The current cylinder is in the cupboard next to my daughter's room so my wife asked me to move the unvented cylinder to the garage if we went with the unvented, but then my double garage would become single as I cant park two cars anymore with the cylinder installed there...

Considering I will be living in this house for a long time so the cost does not play much here, only looking to the best option for the long run.

Thanks a lot for any advice in advance.

 

[Last Plumber]

I know that! However you are assuming that the OP is talking about a pumped heating/"gravity" hot water system. We don't know that. Some people refer to a fully pumped with cold water, from a tank in the loft, feeding the HW cylinder and hence the hot taps as having a gravity HW system, presumably as compared to a direct feed from the mains, i.e unvented cylinder.

I was trying to find out what the OP meant by "gravity HW system".

You are right, I am thinking the OP is talking of a gravity Hot water system.

I answered your post because I thought you were confused about something on your own system and I was trying to help you,

Going of the description and other replies I do think he/she is talking about a gravity hot water system but If i'm wrong fair enough, it is just how it reads to me.

To the OP:-
When you say you have a gravity hot water system what do you mean?
Do you mean that you have pumped central Heating and gravity hot water or is it fully pumped, just so we can all be on the same page?

Not that it's relevant if you're asking about a new system anyway but just so we know what your current system is.

 

[doitmyself]

You are right, I am thinking the OP is talking of a gravity Hot water system.

Unfortunately you have fallen into the same trap as the OP - it's so easy!! Do you mean a pumped heating/gravity HW system, or a fully pumped system with a cold tank in the loft feeding an unvented HW cylinder?

Fortunately your question to the OP is clear.

 

[Last Plumber]

Unfortunately you have fallen into the same trap as the OP - it's so easy!! Do you mean a pumped heating/gravity HW system, or a fully pumped system with a cold tank in the loft feeding an unvented HW cylinder?

Fortunately your question to the OP is clear.

I haven't fallen into a trap at all.
I know what I am talking about.

If the OP is describing something in a misleading way or if he / she is using incorrect terminology that is not a fault of mine.

It is understandable of course as there are a lot of do it yourself people and laypersons, who use this forum for information.

Just to be crystal clear with you.
I am thinking that the OP has an open vented, tank fed domestic hot water cylinder, made from copper, which is heated using gravity circulation from a boiler.

Is that what you think ?


Most heating engineers or plumbers discussing gravity hot water would be thinking of how the water is heated as opposed to it being mains or tank fed !

 

[ShaunCorbs]

Unfortunately you have fallen into the same trap as the OP - it's so easy!! Do you mean a pumped heating/gravity HW system, or a fully pumped system with a cold tank in the loft feeding an unvented HW cylinder?

Fortunately your question to the OP is clear.

I maybe thinking of someone else but wernt you banned last year ?

 

[rpm]

I maybe thinking of someone else but wernt you banned last year ?

Yes he was, think it was for arguing about signing off boiler installs done by somebody else or something along those lines concerning gas works.
Shaun, everyone was unbanned as part of the recent restructure.