Gravity hot water system - improvement ideas please advise

[Sup9]

Hello all,

I currently have a gravity hot water system - 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.

 

[Mottie]

I've just had the same done. Removed cold storage tank and had an unvented hot water cylinder fitted. Now I have mains pressure hot and cold water all round the house. The hot water cylinder MUST be fitted by an approved installer and there are a few safety's on it that when installed correctly, it should be as safe as anything else. It sounds like the bloke was trying to frighten you with scare tactics and on that basis, I wouldn't use him on principal. Make sure it is done by a 'Gas Safe' plumber and they should notify the local council building control on your behalf after the job is finished.

Basically, the Gas Safe engineer reports it to the Gas Safe register, they notify your local council building control department and the Gas Safe register send you the certificate, not the plumber/engineer.

 

[winston1]

If you are changing the cold water tank raise the new one on a platform in the loft as high as possible. This should then give you enough pressure for the showers without pumps.

 

[endecotp]

I am seriously put off by the possibility of it exploding.

Make sure it is fitted by someone who knows what they're doing, and serviced periodically.
They have multiple redundant safety devices.

Gas, generally, has the potential to blow up your house. The additional risk from an unvented cylinder is small.

 

[DP]

22l/ min obviously better than a dribble you are getting at present, so I would be leaning towards the UV cylinder.

 

[Sup9]

I've just had the same done. Removed cold storage tank and had an unvented hot water cylinder fitted. Now I have mains pressure hot and cold water all round the house. The hot water cylinder MUST be fitted by an approved installer and there are a few safety's on it that when installed correctly, it should be as safe as anything else. It sounds like the bloke was trying to frighten you with scare tactics and on that basis, I wouldn't use him on principal. Make sure it is done by a 'Gas Safe' plumber and they should notify the local council building control on your behalf after the job is finished.

Basically, the Gas Safe engineer reports it to the Gas Safe register, they notify your local council building control department and the Gas Safe register send you the certificate, not the plumber/engineer.

Thanks for the explanation, much more clear now.
And I actually picked the engineer from the manufacture's approved installers' list so I think he's qualified - just bad sales technic I guess...

If you are changing the cold water tank raise the new one on a platform in the loft as high as possible. This should then give you enough pressure for the showers without pumps.

I check the head room above the current tank, I think I can move it up 1.5- 2 meters the most, so probably not giving me enough pressure to make a differences?

Make sure it is fitted by someone who knows what they're doing, and serviced periodically.
They have multiple redundant safety devices.

Gas, generally, has the potential to blow up your house. The additional risk from an unvented cylinder is small.

So if all things done right, would it worth to install the cylinder in the garage instead of the airing cupboard where the current vented cylinder is installed? there's about 300-500 additional cost for installing the cylinder in the garage and the fact that the double garage will be come single because of the space the cylinder takes...

 

[Sup9]

oh and thanks all for the replies. All seems prefer the unvented cylinder, is the cold water tank type is really phased out now?

 

[Mottie]

So if all things done right, would it worth to install the cylinder in the garage instead of the airing cupboard where the current vented cylinder is installed? there's about 300-500 additional cost for installing the cylinder in the garage and the fact that the double garage will be come single because of the space the cylinder takes...

Initially, my plan was to have the cylinder fitted in my loft next to the boiler to gain an extra cupboard downstairs but that idea was overridden by my wife who wanted to keep it where the vented cylinder was so that she retained an airing cupboard. Oh, and get one bigger than you have now - as it is mains pressure hot water, you get a nice powerful shower but it don't half empty the tank quickly!

For what it's worth, practically no heat is given off by the new hot water cylinder as it's super insulated. Our airing cupboard heat comes from all the surrounding pipework.

Here's mine mid-install.

 

[winston1]

I check the head room above the current tank, I think I can move it up 1.5- 2 meters the most, so probably not giving me enough pressure to make a differences?



So if all things done right, would it worth to install the cylinder in the garage instead of the airing cupboard where the current vented cylinder is installed? there's about 300-500 additional cost for installing the cylinder in the garage and the fact that the double garage will be come single because of the space the cylinder takes...

If the existing shower head is just below the ceiling the head is around 1 metre. Moving the tank up 2 metres will triple the head. I've done it in all 3 houses I have owned and it was certainly worth while.

Re the garage. If you end up with a long run from the cylinder to your taps it will take ages for the hot water to arrive. Think abput it, more losses as the hot water left in the long pipe just gets cold before you next need it. And don't forget the moans from the misses as to why it take so long to get hot water.

 

[endecotp]

would it worth to install the cylinder in the garage instead of the airing cupboard where the current vented cylinder is installed?

I don't think so.

But maybe the fear of a nocturnal explosion will cause you and your wife to have nightmares, argue, and eventually divorce.

 

[Mottie]

I haven't had any nocturnal explosions since I was a teenager.

 

[Sup9]

think I'm going with unvented cylinder, and maybe the boiler at the same time.

I'll picking the installers from the manufacture site, if the difference on quote from a bronze install and silver installer, does it worth to go with high rated installer? or does the maufacture only rating them based on the number of systems they installed, not the best skilled (but the more they install the better skilled?)

 

[Mottie]

Why not get a gas safe plumbing company to install it. I had the unvented hot water tank, 2 motorised valves, 2 expansion vessels, heating system converted to a sealed one,cold water storage and heating header tanks removed, powerflush whose system, new digital controller and room thermostat, an automatic bypass valve and a service on my boiler (only service it's had since being installed 25 years ago!) and paid £2365 inc vat by a local gas safe heating company. With all that done, it's all set up so that if and when the boiler packs up in the future, all I have to do then is get a new heat only boiler and magnetic filter.

 

[Sup9]

Why not get a gas safe plumbing company to install it. I had the unvented hot water tank, 2 motorised valves, 2 expansion vessels, heating system converted to a sealed one,cold water storage and heating header tanks removed, powerflush whose system, new digital controller and room thermostat, an automatic bypass valve and a service on my boiler (only service it's had since being installed 25 years ago!) and paid £2365 inc vat by a local gas safe heating company. With all that done, it's all set up so that if and when the boiler packs up in the future, all I have to do then is get a new heat only boiler and magnetic filter.

that sounds very good value of money for all the works carried out. I had been quoted for 2.3-3k for cylinder installation and upto 4k for Vaillant boiler installation - that's all quoted by manufacture accredited installers. A local gas safe plumbing company might do it cheaper if they don't do the manufacture accreditation courses?

 

[Mottie]

Once it has been done by the gas safe engineer, he sends off details to the Gas Safe Register who then issue you a certificate of installation and, on your behalf, notify the building control department of your local authority.