Varying boiler temperature

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Tetrarch

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I look after a commercial property where the heating needs renewing.
The hall is occupied by a nursery Mon-Fri (more on that later) and various hall renters of an evening, plus weekends

I have a control issue that I would like some help with

Background

Uninsulated brick-built 20m x 10m x 5m hall
Legacy 2 x 7kw gas-fired end-of-life heaters removed for re-flooring
BTU calc 100K+

Plumber Proposal

6 x Rads, combi-boiler

Use-case

The use of the hall requires rapid heating when the user arrives, so the previous thermostatically-controlled 7kw gas heaters were perfect. A combi set at 60-deg with these six radiators would (I hope) go some way to replicating this rapid heating

Dilemma

The problem is that the regs ( https://www.legislation.gov.uk/uksi/1999/2/regulation/20/made) dictate that either the rads are in a safety cages (£3K+ for 6) OR that the flow temp is set to <=43-deg C, which is, of course, incompatible with my usage requirements

Is there a control system whereby we could control the flow temp of the boiler on a schedule to reduce the flow temp during certain times?

I'm open to a smart, remote system as well, though we'd need to install internet

Regards

Tet
 
The hall is devoid of any insulation whatsoever and retrofitting would be prohibitively expensive. Running any kind of electrically powered heater would be considerably more expensive than a fossil-fuel powered setup - the only other choice is a pellet boiler (like I have in my own home) - that however needs too much time to maintain

Regards

Tet
 
gas112 said:
The best thing to do is fit heaters again.
Click to expand...

Is there a similar wall-mounted gas heater that you can recommend? The legacy pipework is buried in the floor so a new install will need a fairly lengthy new gas supply pipe run

Regards

Tet
 
Tetrarch said:
Is there a control system whereby we could control the flow temp of the boiler on a schedule to reduce the flow temp during certain times?
Click to expand...

Who is responsible for making sure the heating is at the correct temperature for hall usage?

I would imagine a good smart system would be the way to go, as then you could probably program it remotely to pre-heat the hall for bookings.

It's not usual to be controlling flow temp, that is usually left alone I believe, and I don't think you'd want to be messing around with that. Better to have a smart system where you can pre-heat.
 
Firstly that's a very clear statement of the problem and you are correct that the proposed system will give relatively long warm up times

You say the demand is over 100,000, btu

Do the existing heaters give enough heat? The pair of them are only rated at 48,000 btu

G112 has suggested the same sort of units you already have. They work very well

Judging by your answer to Scally you didn't realise the heaters he linked to work in conjunction with a gas boiler

Or you can go for direct fired gas heating.

My advice would be to find a decent commercial gas fitter that can offer all options. If your current person is domestic they can only offer a domestic solution...
 
Razor900 said:
Firstly that's a very clear statement of the problem and you are correct that the proposed system will give relatively long warm up times

You say the demand is over 100,000, btu

Do the existing heaters give enough heat? The pair of them are only rated at 48,000 btu

G112 has suggested the same sort of units you already have. They work very well

Judging by your answer to Scally you didn't realise the heaters he linked to work in conjunction with a gas boiler

Or you can go for direct fired gas heating.

My advice would be to find a decent commercial gas fitter that can offer all options. If your current person is domestic they can only offer a domestic solution...
Click to expand...

Thank you for such a detailed reply.

You are absolutely correct, I failed to read Scally's recommendation properly. I really like the idea of high-level heaters. That frees up the floor space and both avoids (most) potential damage from ball games and investigative little fingers

Our old heaters were two of these:

rinnai.co.nz

Rinnai Energysaver 1004FTR - Rinnai

rinnai.co.nz rinnai.co.nz

and their max output is 8.2kw - does that equate to only ~50K btu?

I think that you are correct inasmuch as I am being shown a domestic solution for a commercial property. I am rather tied to the plumbing company as they are very generous in their pricing (we being a charity) and they have helped me out at very short notice for my own property as well.

More investigations underway - thank for the help

Tet
 
Tetrarch said:
Thank you for such a detailed reply.

You are absolutely correct, I failed to read Scally's recommendation properly. I really like the idea of high-level heaters. That frees up the floor space and both avoids (most) potential damage from ball games and investigative little fingers
Click to expand...
It was a mental picture of more and safer floor space combined with a 'curtain' of heated air that turned my memory to many years back when I was asked about the most effective way to heat a somewhat large village hall. Boiler fed downflow heaters proved to be an efficient and quick way to heat a cold hall that had been closed up over a frosty night. This is why a somewhat old and reprobate scallywag shared his years of experience(y)
 
There are 3412 btu in 1 kW if that makes your maths easier.

If the company are only registered for domestic then an ordinary boiler and blown air are definitely the way to go. At least anyone can work on it then
 
Thanks to everyone for their advice - especially Scally. I did indeed go to Smiths and ended up with two 150mm Caspian heaters. This coupled with a new combi boiler give a really neat solution that did everything I originally asked for

1758727737561.jpeg


I do however have a follow-up question

I'd like to make this idiot-proof (and believe me it is needed!)

We had a regular wireless thermostat provided with the install, but that gives the hall users WAAY too much control for my liking. I would like a thermostat where I can limit the max temperature setting - ideally I'd like an on/off time-limited control, but I don't know how to add that to the existing set-up

Regards

Tet
 

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