Can I pair up 2 Santon Cylinders with this new Worcester Boiler?

Hi all

Bit of a story here. We moved into our house in March 2021 and had lots of jobs to do. On buying the house we were told that the current Boiler was not fit for purpose and we received a £2,500 rebate off the house price so we could get a new boiler fitted. So, the new Boiler was fitted (see photos) etc and all seemed to go well. A lot has happened since and we simply cannot get hold of a local company to assist us further.

To cut a long story short we now know that despite our new, all-singing, all-dancing boiler the actual Water Cylinder (Santon) is simply not big enough to hold the amount of Water for all our family to take a decent shower in the morning. Splitting shower times is simply not an option. Therefore, I did a bit of research and am hopeful that we may be able to fit another (2nd) Identical cylinder in the loft. So, I would be grateful if you guys would have a look at the pictures I have attached and the description below and (hopefully) tell me if we can simply add a second cylinder to the system. Ie...Can this Worcester system work with 2 cylinders? We can't have a larger cylinder because as you can see from the photos the current cylinder is nearly touching the roof and the sides of the loft. Also, a mate of mine told me that the joists may not be able to hold a larger cylinder on that side of the loft. So, to give you guys an idea... I climb onto my loft ladder and walk up a few steps. Just in front of me to the left (11 Oclock) the Boiler is situated on the wall facing me. If I look further left (to 9 O Clock) the Santon Cylinder is there. If I look right (toward 3 O Clock) on the other side of the loft there is an identical space where I could fit an identical Cylinder. So, I do have the actual space for a second cylinder but am curious as to will this work? Can I do this? Can I have 2 Water Cylinders?

First thing I'd check is that the roof joists are strong enough to support the load. You've already got one 250kg cylinder perched up there and you are proposing to double that.

Next question I'd have is how many showers of what duration and flow rate(s) are you trying to achieve? You've got 210 litres of stored water at, say 60°C and if you have the boiler programmed to supply 18kW to its coil while the shower(s) are in use that's quite a lot of hot water to play with.

I'm a big fan of Mira Eco shower heads, they might be all or part of your solution.

That green fixing bracket is duplicated on the right.
Looks like the Cylinder is on a "Shelf" held up by the steel brackets and bolted to the wall with 5 fixings each side, 1 in each block?

Is that the plan for the second cylinder, if so the weight isn't on the joists?

Configure it as HW priority instead and store HW at a higher temperature. 210L is a largeish cylinder, sounds more like system configuration/ not running it right to me.

Thank you for the comments all. I should have said that the ceilings are down in the room below which gives me perfect access to fit another weight-bearing bracket. That, hopefully, will take care of the weight issue. With regards to the other stuff you have kindly mentioned the problem is...
I run a bath (about half full) at 6am. The wife has a 10 minute shower at 6:15 am. When the first (of 3) kids comes to use the shower at 7am the water is now only Lukewarm or in some instances cold. If I was to run a full bath then the wife would only get a 5 minute shower and the 3rd person would have cold Water.

Frank Sebem said:

Thank you for the comments all. I should have said that the ceilings are down in the room below which gives me perfect access to fit another weight-bearing bracket. That, hopefully, will take care of the weight issue. With regards to the other stuff you have kindly mentioned the problem is...
I run a bath (about half full) at 6am. The wife has a 10 minute shower at 6:15 am. When the first (of 3) kids comes to use the shower at 7am the water is now only Lukewarm or in some instances cold. If I was to run a full bath then the wife would only get a 5 minute shower and the 3rd person would have cold Water.

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What timings have you got in for HW & CH. the HW should easily recover before 7am after the 6.15am shower.

As I said you probably need to look into HW Priority.

EvilDrPorkChop said:

What timings have you got in for HW & CH. the HW should easily recover before 7am after the 6.15am shower.

As I said you probably need to look into HW Priority.

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Hi Pork Chop...

Where do I look for the timings? On the next home app on phone? On the Boiler? On the Cylinder?

EvilDrPorkChop said:

Configure it as HW priority instead and store HW at a higher temperature. 210L is a largeish cylinder, sounds more like system configuration/ not running it right to me.

Click to expand...

There seems to be a balancing gate vale on the coil outlet?, if this is throttled in too much then the 18kw coil rating can be anything really.
It also states "draw off to 40C 199.4Lires" what does this mean?
Boiler water temperature and cyl stat setting also important.

Frank Sebem said:

Hi Pork Chop...

Where do I look for the timings? On the next home app on phone? On the Boiler? On the Cylinder?

Click to expand...

What do you use to control the system?

On your programmer if you have nest via the app or if you have a manual one on there set it to come on from 5am and to go off at 9am in the morning

RESOLVED

Hi everybody

Thank you for your input. This matter is now resolved.

I wrote to Baxi and they replied as follows:

You can install two of the same size cylinder but they would need to be in parallel with each other so as to keep everything balanced for the hot water side of your system.

The current cylinder looks like it is on a load-bearing wall and sitting on a bracket that appears to be taking the load of the cylinder. We don’t supply this bracket and you would require to get someone to make one up for you or make sure your joists and beams can take the weight of both cylinders sitting on them, which may require a structural engineer to do this for you.

Your Worcester Bosch boiler in theory should be able to heat up both cylinders, but will need to be piped up to do so and wired up so that the boiler heats both cylinders at the same time.

I would advise looking for a local G3, unvented qualified engineer/installer in your area to check your loft area out and the proposed location of the cylinder.

Indeed, I did as Baxi suggested and I have now found a local G3, unvented qualified engineer/installer to carry out these works.

Thank you to everybody who assisted me with this.

Frank Sebem said:

You can install two of the same size cylinder but they would need to be in parallel with each other so as to keep everything balanced for the hot water side of your system.

Click to expand...

Achieving balanced consumption is going to be a lot easier said than done particularly if the tanks aren't side-by-side and identical so the pipework can be precisely mirrored. You may need a secondary return loop to mix the two tanks to achieve good results.

To be honest, I don't see why your current tank and boiler, properly programmed, can't meet the demand outlined above. Perhaps I've missed something under all the adverts...

Good luck, anyway. Let us know how you get on once the new system is installed.

I think a lot of us suspect your cylinder is not being fully heated with current settings. You seem to have fixated on your solution of a 2nd cylinder. If that cylinder too is under heated, your solution will only help Santon’s profits. The lack of insulation on your system pipe work suggests not the world’s greatest installation, maybe poorly set up.