Quote for heating system - sound reasonable?

[gasafengineer]

. Boilers should be sized correctly, its not hard.
!

Exactly.......................5 bed house with proposed extension? , 210 litre would require 30+kw for a 20 min recovery time...............maybe all the kids can shower @ different times?

 

[mickyg]

. Boilers should be sized correctly, its not hard.
!

Exactly.......................5 bed house with proposed extension? , 210 litre would require 30+kw for a 20 min recovery time.

So where's this 210l unistor with a 30kw coil? And even if this was the case whats wrong with a 30kw boiler?

 

[gasafengineer]

So where's this 210l unistor with a 30kw coil? And even if this was the case whats wrong with a 30kw boiler?

I guess the OP could programme the heating to OFF while HW demand is @ it's peak. .....................why?

 

[mickyg]

sorry, for me there is no argument for sizing a boiler to have heating and a large hot water demand at the same time.as long as the cylinder is correctly sized you wont have this problem.

 

[gasafengineer]

Each to there own Mickyg , no problems here.............................although a 210/300 litre cylinder won't last very long with a large family all using the shower for 20/30 minutes @ a time , yer can't fit a quart into a pint pot.

 

[Boilerman2]

The size of the boiler is probably taking into account the proposed basement extension??? range rated boilers can be de-rated (top end)
as for a month?? it could well take a month to do a quality install in a house of this size especially if it is occupied during this time
£8k seems a reasonable quotation for the scale of the work -how is the installer proposing to get rid of the asbestos flue?? he will need a waste carriers licence to remove this legally and the cost to off load it at a licenced asbestos waste centre will cost £100-£150!!

 

[gasafengineer]

its massively oversized, the difference is the lower end modulation, which on the 637 is 12kw ! with a low demand in milder weather the boiler can be cycling needlessly Should also mention the £160 difference in price !

£160 would be negligible on the cost of job , peace of mind for those cold winter days/nights.

12kw/40k btu lower end modulation would be fine considering the size of house bearing in mind it was built in the 70s , i don't see much difference between a 31kw/37kw regards low end modulation (2kw/7k btu).

 

[ianniann]

The BG 330+ is range rateable down to 9kW. I assume it also modulates itself down to 9kW? Specs say not, but I think that it must. This is a re-badged Vaillant, isn't it? Still looks over-sized, but maybe you have poor insulation.

12kw/40k btu lower end modulation would be fine considering the size of house bearing in mind it was built in the 70s

I'm pleased to see living proof that even "gas safe engineer"s can be hopelessly uneducated regarding boilers. That house, 90% of the time, will need only a kW or two of heating. It is unfortunate that most boilers won't modulate down that low, but the lower the better. The Vaillant ecotec 615 (suitable for a well insulated 5 bed detached) modulates down to 5kW, while the 624 (for a poorly insulated 5 bed detached) only goes down to 9kW, and the 637 (massively over-sized) modulates to 13kW. An over-sized boiler doesn't give you piece of mind, and is actually more likely to break than a correctly sized one. I heated my averagely insulated 5 bed detached house through the last two winters with only 10kW.

 

[gasafengineer]

That house, 90% of the time, will need only a kW or two of heating. .

....................priceless

Where are all these 2kw boilers installed?

 

[mattnickh1]

without sizing rooms and rad out puts, cannot comment on size of boiler, but would of thought required more than 24kw. All rads should not be on thermostats... 10% of system should be on lockshields. I too do not believe in fitting the smallest boiler to fit the situation, especially as the client is intending to extend. It is better to modulate down than have an appliance running at max value and not achieving correct heat values, imho.

 

[hansthebear]

it could well take a month to do a quality install in a house of this size especially if it is occupied during this time

I dont actually think I could physically work slowly enough to spread a 12 rad heating system out over a month, each to their own etc.

 

[Boilerman2]

Perhaps it is because I have worked on installs that have taken a team of 8 pipefitters/welders, plumbers & Commissioning engineers over a year to complete a system, one job i worked on took 3 months just to commission!

 

[gasafengineer]

Perhaps it is because I have worked on installs that have taken a team of 8 pipefitters/welders, plumbers & Commissioning engineers over a year to complete a system, one job i worked on took 3 months just to commission!

 

[Gasman77]

Stick with the 37kw , these can be range rated if necessary , all too familiar to see UNDERSIZED boilers.

Balls.

 

[gasafengineer]

Balls.

Good to see your knowledgable posts yet again , you never fail.