14 ensuite rooms, 3 x 300 litre unvented cylinder's, BOILERS ????

[hickings]

hi, I have been asked to finish a guest house which has 14 unsuite shower rooms. the old builders and plumbers have been kicked off for being too slow. the owner just wants it all finished now.
there is a 28mm hot feed, 22mm secondary return and a 22mm cold all already go to each room which I have pressure tested already. the incoming mans is a 50mm feed.
there will be just four radiators in communal areas.
all rooms will have air conditioning for heating/cooling.
they want 3x300 unvented cylinders which I will have no problem linking up.

PROBLEM
they want 2x 24kw Worcester Greenstar 24i System Boiler, with a low loss header.
i understand the owner wants two boilers linked together one for back up.

my issue is i think they are over kill for 3 cylinders and 4 rads

is there a better way to link the two boilers without using a low loss header and without multiply pumps as there is not much heat output needed. its not a cost thing.
i just wanted to here anyone else's suggestions?

 

[happyflyer]

Hicking,

There are too many ifs and buts here, I would get someone to have a quick look at it for you, for instance the 50 mm incoming means nothing if its only 0.5 bar, there are lots
of pitfalls, where is the job. As a few have said the 28 mm for 14 showers etc sounds a little light, if you want to allow for a lot of diversity, then be it on your shoulders.

Normally with this size of a project you would have a break tank on the GF with large storage and a booster set H/C then the mains does matter too much as long as it can fill
the tank and there you have some built in diversity with storage and backup if the mains falls over.

Don't let the client start pushing you where you don't want to go, if it doesn't work you will be the one that doesn't get paid.


Best of Luck Tony

PS you need to take care how you pipe up the three Mega flows the pressure drops need to be equal on the secondary side

 

[Ermintrude]

Give

Shaun Helme (head of UK sales) 07887758602 a ring at ACV he will direct you to local bod and thy will fully spec out the system
.

They do an Andrews type heater also.

The jumbo can be cascaded


Sorry original comment LLH or reverse return .

 

[happyflyer]

Spot on Ermi about LLH or RR.

 

[Killy Bing]

The more i think about it. 300 litre megaflows arnt suitible, even three of them!! You need the recovery rates of an acv.

 

[happyflyer]

Still, KB I think you can get nearly 100 kws of heat into three MF, thats going to take two 40 CDi banging away, it needs a design engineer IMO

Cheers

 

[Ermintrude]

Cram. 240kw into to 800 jumbs

 

[chris watkins]

Cram. 240kw into to 800 jumbs

Just remind us Ermi, how many shares do you now hold in ACV ???? LOL

 

[chris watkins]

Hi hickings
Have you agreed to take on the design liability for this project, if yes, what PI insurance do you carry? You can always get a third party (consultant) to carry out a design review (client pays for) which both of you can agree on works required, then you can concentrate on the install. If not, then don't get involved in the design but put this in writing along with any concerns you may have on the proposed / already installed.

300i Megaflo coil = 24.5 kW (x3 = 73.5 kW) with 2x24kW boilers recovery of 70% will be around 42mins with full 73.5 available recovery would be around 28mins.

 

[happyflyer]

Well said Chris , spot on, he still needs to think about that 50mm MCWS will it do the job ??? looking down the hole in the end of the pipe won't tell him!!!

Tony

 

[happyflyer]

If you start converting this project over to high output gas water generation and reduce the storage, you may be in danger of running out of
gas, it will need a bigger main to drive these units, holding water in storage does not load up the gas main as much, we don't know what the gas main
size is, too many questions and not enough answers, he needs to come back to us with more details.

Tony

 

[wetdrip]

As an engineer with a keen interest, non-plumber. The lighting-fast replies from all the extremely knowledgeable forum members is what keeps me coming back to this site.
Great stuff from you all.

 

[Ermintrude]

Just remind us Ermi, how many shares do you now hold in ACV ???? LOL

Nearly was engineer for them once. Do u want my shares Certs. Got a few BDR and BG ones!

Heat recovery any one? What abut a bit o biomass?

 

[chris watkins]

Nearly was engineer for them once.

You don't say!!

Do u want my shares Certs.

I will have anything you have got, my pension pot is empty, never worked any where long enough to build one.

 

[happyflyer]

I think hickings has gone it alone or walked