Which Boiler(s) for large HMO 15-bed

[shaftyboss]

I'm looking for a new system to provide heating and hot water for a 15-bed HMO (all rooms are ensuite) in a 5 storey building, 11m x 8m footprint (440m2).

CH: approx 20 rads + 15 towel rads (150,000 BTU approx)

DHW: 15 showers + kitchen
Assuming, no more than 10 people will shower at any one time and if i fit a flow restrictor at 6L/min then that means I need 60L/min max. If each shower takes 5min then a 300L cylinder should be ok?

what is the size of boiler(s) and cylinder(s) I need. I have talked to some plumbers but they vary from one big domestic boiler (vailant 637) to two commercial boilers (vailant 65KW). Some say use Andrews water heaters... so I am confused and would appreciate some advice. Once I know what system I need then i can get a quote and get started.
Much appreciated

 

[Biggles..]

To be honest, personally I'd charge you to tell you what your after, guarantee it will work and give you a tender document.
asking on a DIY forum is going to get you loads of mixed reviews.

 

[scoobydo123]

300L nowhere near enough. Need to know what the flow is like into the building. Buffer tanks and part gravity maybe required.

 

[Biggles..]

45litres per person stored would be the cibse recommendation.
This is why you can't just get a plumber to dream up a number.

Proper design comes with a price tag, most will avoid this and pay the price later when it falls down around them.

 

[ScottishGasMan]

As the other guys say. This is a massive project for a DIY forum. There are far to many vairabiles to just tell you what "System" you need.

As lee says, it would take enough time and knowledge that they would in most likley hood charge you to check over the property fully and give you an agreement that would suit.

Its much less to do with what boiler you need and much more about how the system is set up and put together.

 

[shaftyboss]

what kind of cost am i looking at to spec this up then, Lee

 

[Biggles..]

% of tender or fee, but you'll be looking a couple of grand plus for a design.

 

[Dan Robinson]

***


Cylinders might not be the best way to go here either.

 

[Biggles..]

Would depend on the gas supply.

Be fun trying to watch a standard 300l cyl try and get 60l/min out its outlet.

One thing is for sure, having done 200ensuite rooms last summer, you can guarantee that theirs 2 in a bed with the room designed for sole habitation.

 

[Dan Robinson]

Water supply will be an issue too...


I know where. NOT to source your break tanks and pump sets.

 

[Norcon]

Didn't realise you needed credentials to post on here.

 

[Agile]

***

Your first problem is finding where to get a dynamic flow rate of 60 li/min @ 1.0 bar unless you have a break tank and pressure pumps.

I would specify a 300 li UV cylinder for a family of five!

Tony

 

[Dan Robinson]

Nobby, based on your inability to back anything you post up with fact then what you say is true. . Remember, next time you search Google images for pictures of pipe work, use decent examples .


Tony, mare, is there anything other than dynamic flow?

 

[Agile]

If it is for driving showers its only the dynamic flow rate which matters!

 

[Dan Robinson]

So you don't think static flow would be an issue?