Boiler Type/Size ?

[Sukh]

Hi all,

I’m in the process of converting a property to a 9 bed B&B. All rooms will have an en-suite. I was planning on installing a Vaillant Eco Tech 37kW boiler and 300 litre indirect hot water cylinder with dual coil. We have a 50mm supply coming into the property at a pressure of 3bar. I just wanted to check if this system is suitable for the property or should I go with a commercial boiler and/or different system? My installer seems to think that the boiler won’t be able to handle it and will start to have to have problems in a year or so.

Thanks,
Sukh

 

[Millsy 82]

I would be looking commercial water heater myself.

 

[Ray Stafford]

It doesn't sound like enough hot water to me.

Download size it from Baxi Commercial site here.

I ran it based on the limited information that we had, based on baths in the ensuites (not showers) and it suggested 600 litres of storage, not 300.

However, there are lots of variables, so download it yourself, fill in all the options, and hit the "size it" button.

Edit - also, if you really want to be sure, retain a consulting engineer with proper professional liability indemnity insurance. This isn't going to be a cheap job, and isn't really suitable for designing via an internet forum.

 

[morganb]

I'd double up on everything (eg 2 smaller boilers instead of 1large) with something like this so you have a back up if one fails. It also means you only need to run one boiler if the load is low, or heat one cylinder if the occupancy is low. Also 300l storage seems far to small.

 

[bigads28]

I'd have 2 boilers and 2 cylinders with secondary returns depending on length of runs.

 

[Killy Bing]

The boiler handling it wont be the issue...

B and b requires a commercial solution, i would say a standard 300 litre unvented is very much a medium to large domestic solution!
You mention a duel coil, if you plan to use a solar cylinder with both coils linked in series forget it, if linking in parallel you may find the boiler is not man enough.


i would be thinking more along the lines of two boilers ( reputable ones) which also gives you some back up if one fails , the other can limp along somewhat.
i would look at ACV to offer a solution, their tank in tank designs are far better for recovery times and the amount of ho****er supplied, the low end ones allow around 70kw of heat to be absorbed at any given times, standard unvented cylinders are around 28kw at the very high end!
another option would be andrews water heaters for the ho****er and a regular boiler for the heating.

also another consideration is the flow rate of the 50mm at peak use, an accumulator or two could be installed to give insurance of the flow rate not dropping at peak use mid shower.

you will certainly want a secondery return to give instant hot take off to all outlets.

now as you're converting it you'll want to save money BUT

heres my tidbit of advice

if i'm at a hotel or b&b and my or my partners shower goes cold at anypoint or it runs to a trickle then i'm one peed off customer who won't be returning and if asked i would say don't bother going there.

so spend the money now or risk a crippling bad online review!


P.s id have a 3rd party company design it and insure the design as ray has said.....

 

[happyflyer]

Hi all,

I’m in the process of converting a property to a 9 bed B&B. All rooms will have an en-suite. I was planning on installing a Vaillant Eco Tech 37kW boiler and 300 litre indirect hot water cylinder with dual coil. We have a 50mm supply coming into the property at a pressure of 3bar. I just wanted to check if this system is suitable for the property or should I go with a commercial boiler and/or different system? My installer seems to think that the boiler won’t be able to handle it and will start to have to have problems in a year or so.

Thanks,
Sukh

I would get some proper advice you don't want guesswork or you will end up with some very high rate B&Bers and you won't win Four in a Bed, it will cost you but be well worth it. Take notice of Ray Trafford he is taking sense.

 

[AWheating]

get your/a installer to design and spec the installation or get it designed and your installer can quote to the design.

 

[Ermintrude]

ACV will spec it for you. At a guess Jumbo 800. It produces nearly 2000l of shower water in first 10 mins.

But you better have some kick bum boilers attached. 120kw!

 

[doitmyself]

the amount of ho****er supplied,

This occurs regularly in many topics, so it's no dig at you.

You wouldn't get the **** if you typed hot water or hot-water. In any case there is no such word as h-o-t-w-a-t-e-r.

 

[josh]

I would get some proper advice you don't want guesswork or you will end up with some very high rate B&Bers and you won't win Four in a Bed, it will cost you but be well worth it. Take notice of Ray Trafford he is taking sense.

Lol enough said, you wont win four in a bed, have seen one where they didn't have any hot water for the shower and i don't think they won so its true!
defiantly needs sizing by the book though.

 

[Sukh]

Thanks guys, much appreciated. I'll definetly be taking further advice from a 3rd Party. Thanks again.

 

[ringi]

If you can get the tank close to all the rooms and therefore have short pipe runs, consider using a manifold and 15mm pipes to each en-suite, rather than a secondary return as you will get much lower heat losses.

Think about pipe length when planning the building layout, it may even be for example that you come up with layout that has 2 clusters of rooms with their own boiler/tank.

As to tank size, will you have walking groups etc booking all your rooms when everyone comes back cold wishing to have a shower at the same time?