will this work ok?

[mattysupra]

O.k chaps, i have totally given up on getting anyone to actually install my heating system. Im now at over 30 plumbers who simply dont turn up to quote or when they do they say -

- to big a job for me
- i dont know how to do what you want
- a stupid quote of £20k
- A really stupid quote of £120k !!!! WTF ?
- i dont know how to work out the size of boiler you need
- will take me and a mate 3 weeks to install
- you need UFH !
- we will fit a new boiler but we dont want to install a whole new system (this one i have had maybe 10 times)

So, im now looking at fitting the system myself and then getting someone to simply fit the boiler only.

Im looking at a 70kw boiler that will feed 3 x air blowers. They are rated at 2x 18kw & 1x 31kw.
The pipe work will be copper and 22mm all the way (the inlet/outlets on the air blowers are also 22mm)In total i will be using 50 meters of 22mm copper pipe including flow and return.
The 3 airblowers are in separate areas that need to be run at separate temperatures, so i figured i would use motorized 2 way valves that are controlled by room stats in the areas the heaters are in that will also turn the boiler on obviously.

-Does my plan and sketch look o.k?
-Should the valves go on flow or return?
-Will i need a extra pump? does this go on flow also?

any comments or advice welcome.

O and if anyone wants to do this for me then PLEASE contact me on 07971199204 , i really dont want to do this myself. (yes i have asked before on here)




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[adamsheating]

You may find that you'll need to have bigger primaries than 22mm to get that kind of kw passed through them all at once.

i'll do it for £19.5k (but this isnt binding)

 

[ianmcd]

Not sure why you thought the quote of £20K was so outrageous, this is a bit of a specialised job that you are looking at and that as a ball park figure wont be far away

 

[mattysupra]

Not sure why you thought the quote of £20K was so outrageous, this is a bit of a specialised job that you are looking at and that as a ball park figure wont be far away

really ?

materials come to under 4k including blowers, pipe, boiler.

It is a straight run for pipe work, no lifting of floorboards etc. Simple straight run attached to underside of a mez floor.

So labour for this sounds about right at 16k? the chap that quoted 20k said it would take him 3 days.

I work that out at £5330 quid a day labour?

surely that is not correct or am i missing something here?

 

[mattysupra]

You may find that you'll need to have bigger primaries than 22mm to get that kind of kw passed through them all at once.

i'll do it for £19.5k (but this isnt binding)

Thanks, what would you suggest ?

 

[ianmcd]

its to do with the qualifications that the contractor carrying out the work will have to hold and renew every 5 years at a substantial cost, not a lot have commercial warm air and the ones that do quite rightfully charge a premium for carrying out such work , dont blame the installers for the cost its Gas safe/ HSE that make the rules

 

[adamsheating]

You may find that you'll need to have bigger primaries than 22mm to get that kind of kw passed through them all at once.

i'll do it for £19.5k (but this isnt binding)

Thanks, what would you suggest ?

it would have to be properly sized but with that kind of heat input your getting into commercial installation so you start talking low loss headers, shunt pumps, 35mm primaries, huge gas pipes supply etc etc!

I'm primarily domestic but I'm sure you'll incur the wrath of the commercial boys shortly!!! But needless to say on gut instinct, your original design is off the mark.

 

[mattysupra]

if teh price to install is 20k and that is what others quote then that is what i will have to pay.

So far i have only had two quotes back -

1- 20k
2- 120k !

Im struggling to get anyone else to quote tho. They all say to big for them. The commercial heating companys don't want to use a boiler but large radiant heaters or air heat source pumps. Radiant tube heaters are no good to me in the area with only a 3 meter head height in a warehouse mounted above stock, the commercial chaps seem to ignor what will be in there but consontrate on heating a empty area only. It seems they dont care how racking etc will effect teh system. Far enough it was a empty unit but its not going to be. . As for air heat pumps, well i cant afford these and the fact that they all seem to say i should have one but they are unsure if it can heat the place is a bit ...... ummmm.... should you be selling it me on the chance it 'may' work?

 

[Hugh Jaleak]

Gas fired warm air heaters? http://www.reznor.co.uk/

 

[mattysupra]

Gas fired warm air heaters? http://www.reznor.co.uk/[/QUOTE]


thanks, the one company came out and advised these. Im waiting for the quote to come in.

 

[Dan Robinson]

I would suggest you have answered your own questions really.

Champagne ideas, beer money.

Like it or not you are asking for a commercial system. That comes at a premium.

Although "warehouse" seems a little self aggrandising from your descriptions.

I'll direct your thread to one of the commercial guys in the CC and see what he says....

 

[mattysupra]

You may find that you'll need to have bigger primaries than 22mm to get that kind of kw passed through them all at once.

i'll do it for £19.5k (but this isnt binding)

Thanks, what would you suggest ?

it would have to be properly sized but with that kind of heat input your getting into commercial installation so you start talking low loss headers, shunt pumps, 35mm primaries, huge gas pipes supply etc etc!

I'm primarily domestic but I'm sure you'll incur the wrath of the commercial boys shortly!!! But needless to say on gut instinct, your original design is off the mark.

Would the boiler dictate what size pipe to use? if the boiler had 22mm pipe outlet then would it be done in 22mm? or would you step it up to 35mm after boiler? (sorry if a stupid question) or would the boiler already be using say 35mm?

 

[adamsheating]

it wouldn't surprise me if a boiler that size had 1" if not 1 1/4" tappings. I'd be looking at two smaller boilers cascaded anyway, but that is my domestic slant on it. Dan has already passed it onto the relevant critics...

 

[Dan Robinson]

4k materials my Harris

 

[adamsheating]

You may find that you'll need to have bigger primaries than 22mm to get that kind of kw passed through them all at once.

i'll do it for £19.5k (but this isnt binding)

Thanks, what would you suggest ?

it would have to be properly sized but with that kind of heat input your getting into commercial installation so you start talking low loss headers, shunt pumps, 35mm primaries, huge gas pipes supply etc etc!

I'm primarily domestic but I'm sure you'll incur the wrath of the commercial boys shortly!!! But needless to say on gut instinct, your original design is off the mark.

Would the boiler dictate what size pipe to use? if the boiler had 22mm pipe outlet then would it be done in 22mm? or would you step it up to 35mm after boiler? (sorry if a stupid question) or would the boiler already be using say 35mm?

no, the kw of the system dictates what the pipe size is.

this is from another post a few years back

or 1.5 m/s and 20°K temp drop, the carrying capacity of each pipe size is as follows -

8mm = 4.5 kW, 10mm = 7.3 kW, 15mm = 18.1 kW, 22mm = 40.2 kW and 28mm = 67.5 kW.

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