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Boiler for large domestic premises

View the thread, titled "Boiler for large domestic premises" which is posted in Boiler Advice Forum on UK Plumbers Forums.

GQuigley67

Plumbers Arms member
Plumber
Gas Engineer
Went to price job today, current boiler 55kw, customer wants a single large output boiler and was already quoted for 2 domestic boilers linked together which he didn't sound too keen on. His current setup is Ideal Concord C 55kw for heating and a separate water heater for 300L unvented with no efficient controls of the system, and due to the size of property very large gas bills.

All the boilers above 40kw all seem to be classed as commercial by the manufacturer so even though it's below 70kw falls under commercial. U16 meter in property total pipe size without measuring is probably below 0.035m3(total guess but max pipe 35mm)

What qualications would I need as a minimum to do this installation? Or is there any domestic classed larger boilers anyone knows of? (I can't find any anywhere) I had a quick look online but there are so many commercial qualifications it's unreal. I can'tell see me getting into the commercial side here as it will all be tied up by the big boys, but for certain installation types like this it may come in handy if not too expensive
 
i may be wrong but didnt gas safe say aslong as your output and m3/h is below the commercial your ok

(croppie to confirm as im sure hes the one that posted something like that )

and worcester 162 60kw
 
fair enough tbh best way for you is any commercial guys locally that can give you a hand for a day or two?

if not you need i would say

CoDNC1
TPCP1/A
ICPN1
CIGA1
 
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As soon as the manufacturer describes it as commercial or refers to any commercial regulation in the MI's then you need your commercial ticket regardless of if it is below 70kw.
I would love to do my commercial gas but I have zero experience and don't want to go into it completely blind.
 
Checked the commissioning on the WB and it was commercial and it's under their commercial products. Will just have to find a commercial guy.
 
spoke with worcester they say I can fit the 65kw boiler even though they class it as commercial although the commissioning procedure seems different to your normal domestic boiler.
 
spoke with worcester they say I can fit the 65kw boiler even though they class it as commercial although the commissioning procedure seems different to your normal domestic boiler.

Double check with gas safe and your golden then
 
Well it's below 60kw and Worcester even offer to commission it for you for a price so happy days. MI always override I'm sure.

Gas safe was pretty much sayin check with manufacturer. Hope I win job now will be a challenge haha.
 
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spoke with worcester they say I can fit the 65kw boiler even though they class it as commercial although the commissioning procedure seems different to your normal domestic boiler.

No way, if this is true I just missed out on some nice installs. So Worcester say you can fit a 60kw boiler classed as commercial? Are you allowed to commission it?
 
No way, if this is true I just missed out on some nice installs. So Worcester say you can fit a 60kw boiler classed as commercial? Are you allowed to commission it?


Yes you are but if your not too confident you can pay them £200+VAT to do so. The models below 80kw come with a free converter to convert the electrics to accommodate domestic controls.
 
The saga continues...

Spoke to gas safe regarding and they say as far as they are concerned if it's classed as a commercial boiler it's a commercial ticket, so then phoned worcester again (spoke to 3 different ppl there now regarding this) and he's sayin yes as it's classed as domestic under 70kW so he gave me an email address and I'm trying to get this in writing from Worcester.

Gas safe advised me to get it in writing to cover myself, said the manufacturer should make it more clear that it's domestic, and agrend their instructions override gas safe.
 
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The saga continues...

Spoke to gas safe regarding and they say as far as they are concerned if it's classed as a commercial boiler it's a commercial ticket, so then phoned worcester again (spoke to 3 different ppl there now regarding this) and he's sayin yes as it's classed as domestic under 70kW so he gave me an email address and I'm trying to get this in writing from Worcester.

Gas safe advised me to get it in writing to cover myself, said the manufacturer should make it more clear that it's domestic, and agrend their instructions override gas safe.

No way. How confusing is that hey. Still we all know MI's overall. Thanks for keeping us updated and please continue to do so
 
Well they've confirmed it in writing, think I'm just gonna quote for the 80kw anyway keep customer happy and get guy in to commission the boiler, customer has heart set on the 80kw for whatever reason thinks he knows best.
 
Well they've confirmed it in writing, think I'm just gonna quote for the 80kw anyway keep customer happy and get guy in to commission the boiler, customer has heart set on the 80kw for whatever reason thinks he knows best.

So, you are allowed to install a 80kw boiler even though your ticket is upto 70kw?
 
I'll be getting a commercial guy to do gas side of boiler, nothing stopping me doing hydraulic side. I will post the conversation between me and technical when I get the chance. They have confirmed.it will work on a domestic S Plan, just need to find large 2 port valves lol
 
I'll be getting a commercial guy to do gas side of boiler, nothing stopping me doing hydraulic side. I will post the conversation between me and technical when I get the chance. They have confirmed.it will work on a domestic S Plan, just need to find large 2 port valves lol

What size? Also look at amz valves and actuators
 
About 1 "1/2 at least, i seen some online a while back around £150. just gave an estimate for the job if they accept will do a more detailed surveyou.
 
So chaps my van decided to pack up today so at home now doing some estimates. Looking g through the gb162 brochure and found this... 20160609_115030.jpg
 
This is correct. There is so much confusion surrounding commercial gas it's untrue. I had a similar question and the following facts apply.

Firstly as long as the boiler is under 70kw ie not a commercial boiler then you can install it, note worcester product you are looking at is a domestic boiler but a large one and is based on commercial design so that's where people can get some confusion. I'm pretty sure also that worcester insist on putting anything above a certain size (I think it's 40kw but don't quote me on it) into a low loss header so as the boiler can keep up with demand.

The next and most crucial part. The definition of commercial gas work is NOT defined by the property type. I see sooooo many people assume this.

It is deemed by the supply size your working on at this property. If the volume of gas installation pipework exceeds 0.35m3 then you must hold commercial acs tickets...

So what I would say to you is when you survey the work you look at the present installation of gas pipework and work out volume. Is it correctly sized for new appliance? If not what size will it have to be and what will the new volume be. If it's getting pretty close to 0.35m3 I wouldn't take the chance.

I got a lot of conflicting info on this but got there in the end. It is definitely down to gas pipework volume and not the property.
 

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