Commercial Boiler fitted in a house?

[AlexCarp]

This Dan fellow has not a clue what he is on about and resorts to insults when proven wrong.

To the OP, take no notice of his incorrect advice. Keep your quality boiler as it is adequate. Just fit a low-loss header which are easy to do.

 

[mogget]

Vaillant state:
"They are configured to automatically optimise heat and hot water supply according to the demands on the system at any particular time."

I looked at the pump needs. The boiler needs approx. 33 litres a minute running through its heat exchanger. After looking on the Grundfos website and the technical specs on the Grundfos 15/50 and 15/60 domestic pumps it would appear that if the speed control switch is set on position 2 on the 15/50 pump a flow rate of 0.84 litres per second is given, giving 50.4 litres per minute. Maybe position 1 is all that is needed, but a check is needed. I would assume similar to a Wilo pump. So a domestic pump is all that is needed between the boiler and the header. So much for a "large" expensive pump.

I see this boiler has a very similar heat exchanger to the 438 etc, which has a famously high resistance to flow. Would you like to repost your flow calculations having taken the pressure drop and pump curves into account?

Even I can see an incomplete 'calculation' here and I'm no gas engineer.

 

[Dean744PiN5]

12kw MINIMUM is no use - ( unless maybe your house doenst have a roof or walls then the heat loss calcs might add up.

To the OP - Do a proper heat loss calc for your house before looking at what boiler you want.

As Dan says, you need commercial for it, LLH - Big Pump and it will turn its self on and off till the death of it. It doesnt light at 12kw. it probably ignites about 30-35kw and holds there for a minute, by which time it will be due to shut off on a severly undersized system

Where a 24kw boiler could heat the place probably no bother and can rate down to 4 or 5kw to maintain that heat (and will still have to shut off and cycle at that)

I doubt you have read all the thread to write misleading advise. Initially this Dan fellow, backed by others, including you, wrote that the boiler was "too big" and would continually cycle on an off. I looked and found it can run down to around 12 kilowatts, so was not too big at all and would not continuously cycle on and off. The OP already has a 28mm gas supply, so no problems there. Then this Dan starts to try and justify his mistake - or more likely defend his wind up of the OP.

I directed the OP to another thread where I fitted a low loss header and Wilo smart pumps for the heating on a 40 kilowatt boiler. It works brilliantly and has been operating for 6 months perfectly giving a wonderful even heat through the house. The OP can also fit a fixed speed pump for the hot water cylinder off the low loss header as well. All he needs to do is get a pump for the header that will give the minimum flow required through the boiler. Being a 12 to 46 kilowatt boiler that will be domestic sized and not cost a fortune.

I have wiped the floor with this Dan fellow, which is not difficult, and many strangely seem to defend when obviously he is wrong, and who resorts to insults when proven wrong.

If I was the OP, I would fit a low-loss header with a pump pumping through it to give a constant flow through the boiler. Off the header have the heating zone(s) using Wilo smart pump(s). Have one fixed speed pump heat up the DHW cylinder off the header. It is best he looks at my post on the Atmos Intergas thread on a guide on how to do it.

Telling the OP to ditch his new perfectly adequate quality boiler to spend around £900-£1,000 on another boiler is grossly irresponsible advise. I did tell the OP to do heat calculations and I am sure the boiler will match his heating requirements. I doubt his 5 bedroom house will need less than 12 kilowatts of heat. His calcs will determine that.

See you ignored my post which showed you up to be the clueless tw@t that you are, again Heat loss calcs are based on worse case scenario of around -3degsC which is a hand full of days a year, the rest of the time the heat loss of properties will be much less than the designed maximum hence oversized boilers WILL short cycle llh or not. Also how do you know a 28mm gas supply is adeqoute have you carried out a pressure loss calculation for the OP's gas system or did you stick your retarded finger in the air and go "ooooh its a big pipe it must be OK" what if he has a fire or a cooker on the supply?
I was speaking to a doctor the other week and we agreed how Google has a lot to answer for, he said to me "everyone is a doctor now because they can look it up" I laughed and said" everyone is also a heating engineer"

 

[AlexCarp]

OP, This is where forums can be dangerous,

Boy you said it!

you will need a commercial fitter to install the appliance

Only if it is over 70 kilowatts. It is 46. A domestic man can fit it.

 

[muggles]

OP, This is where forums can be dangerous,

Boy you said it!

you will need a commercial fitter to install the appliance

Only if it is over 70 kilowatts. It is 46. A domestic man can fit it.

Even though it's classed as a commercial appliance? So does that mean that I can fit a commercial cooker as well, simply because it's under 70kw?

 

[AlexCarp]

To the OP - Do a proper heat loss calc for your house before looking at what boiler you want.

See you ignored my post which showed you up to be the clueless t**t that you are,

You have been proven wrong, so resort to insults. Obviously a poorly educated man who picked things up.

again Heat loss calcs are based on worse case scenario of around -3degsC which is a hand full of days a year,

Read my posts, all was covered.

 

[AlexCarp]

OP, This is where forums can be dangerous,

Boy you said it!

you will need a commercial fitter to install the appliance

Only if it is over 70 kilowatts. It is 46. A domestic man can fit it.

Even though it's classed as a commercial appliance? So does that mean that I can fit a commercial cooker as well, simply because it's under 70kw?

Makers cannot overrule the law. 70 kilowatts is the line in boilers. Under is domestic and over is commercial. By law. A domestic gas meter can cope with approx 63 kilowatts. That is why they set commercial at 70 kilowatts.

Vaillant have a domestic sized boiler and are peddling it as a commercial job. And no doubt hype up the price of course.

 

[AlexCarp]

I see this boiler has a very similar heat exchanger to the 438 etc, which has a famously high resistance to flow. Would you like to repost your flow calculations having taken the pressure drop and pump curves into account?

Even I can see an incomplete 'calculation' here and I'm no gas engineer.

I gave the link to the boiler specs. Go to the pump makers site as well.

 

[muggles]

OP, This is where forums can be dangerous,

Boy you said it!

you will need a commercial fitter to install the appliance

Only if it is over 70 kilowatts. It is 46. A domestic man can fit it.

Even though it's classed as a commercial appliance? So does that mean that I can fit a commercial cooker as well, simply because it's under 70kw?

Makers cannot overrule the law.

Err, yes they can actually - in the gas world, manufacturers instructions ALWAYS overrule all other forms of regulations. If it's in the book, it's a legal requirement. Simples. In this case, it's in the book that the appliance must be installed with reference to commercial gas regulations, hence you need a commercial ticket to install it

 

[mogget]

I gave the link to the boiler specs. Go to the pump makers site as well.

Have done, I make a 15/50 on speed 3 at 350mbar approx 1200 l/h. Well short of the 1935 l/h specified, and this doesn't take account of any other resistances than the hex.

Methinks Alex is talking carp.

 

[AlexCarp]

Err, yes they can actually - in the gas world, manufacturers instructions ALWAYS overrule all other forms of regulations.

Technical movement is very different from domestic or commercial classification.

It is 46 kilowatts. A domestic man can fit it. The law.

 

[mogget]

Haha, just looked at the boiler innards. Seems to have an inbuilt pump!

That'll teach me, it should teach Alex too but I doubt that it will.

 

[muggles]

Err, yes they can actually - in the gas world, manufacturers instructions ALWAYS overrule all other forms of regulations.

Technical movement is very different from domestic or commercial classification.

It is 46 kilowatts. A domestic man can fit it. The law.

The law says that it should be fitted to manufacturers instructions. The manufacturers instructions require that it is fitted by someone with commercial training. Therefore, it can't be fitted by someone with a domestic ticket. Even if you say that it can in bold type. Try using capital letters as well, see if that makes a difference....oh no, the law is still the same, it still needs to be fitted in accordance with the manufacturers instructions

 

[AlexCarp]

I gave the link to the boiler specs. Go to the pump makers site as well.

Have done, I make a 15/50 on speed 3 at 350mbar approx 1200 l/h. Well short of the 1935 l/h specified, and this doesn't take account of any other resistances than the hex.

Methinks Alex is talking carp.

Methinks you pick things up. The standard Grundfos domestic 15-60 gives a maximum of 1.1 litres/s, which is 3960 litres/h. Well over, nearly twice, what the 1935 l/h specified by Vaillant.

The 15-50 gives up to 1 litre/s, which is 3,600 litres/hr. So a cheap 15-50 will do. You would have put in a very expensive pump over engineering the system. tut! tut!

 

[AlexCarp]

It is 46 kilowatts. A domestic man can fit it. The law.

The law says that it should be fitted to manufacturers instructions. The manufacturers instructions require that it is fitted by someone with commercial training.

Wrong. the dividing line is 70 kilowatt. Makers cannot overrule the law on classification.