57kw needed

[KevC1]

Just been to take a look at a job which requires 57kw. It's a big house, and all the radiators have been hung (not necessarily correctly sized), but no boiler fitted yet. I'm proposing to fit a system boiler with an unvented cylinder. The radiators and cylinder will total 57kw.

Just wanting a couple of ideas. The heating has been split into an upstairs and downstairs zone, so I was thinking I might fit two boilers, and run the cylinder off one of them aswell as the downstairs circuit.

What do you guys think?

 

[PEDANTICVINDICTIVEMAN]

I did that years ago, one boiler did downstairs with it's own timer and room stat, the other did upstairs and hot water with timer 3 port valve cylinder stat and room stat, worked a treat, suppose now you could add on weather comp and opentherm stats.

 

[kitch0978]

wat other gas appliances are in the house? if its only got a u6/g4 meter it doesn`t leave much left for cooker/fires....? how many rads has it got.....? much be huge house....

 

[mickyg]

you might be better off with 2 boilers into a header.

 

[KevC1]

It's on LPG with two buried bulk cylinders.

It is a very big house, 8 bedrooms, 30 radiators. It's an old restored hall.

Thanks for the ideas.

 

[PEDANTICVINDICTIVEMAN]

Ahh yes, the one I did was 2no 50,000 btu boilers, yours is rather larger, oeer missis

 

[The Baker]

Whats the exteriour dimentions of the Hall.

Tim

 

[KevC1]

Not sure what the exterior dimensions are. All the radiators have been hung, due to a very expensive oak floor being fitted. I feel they are undersized, but there is nothing that can be done now.

This is why I haven't been able to do a proper heat loss calc. I've just totalled all the rads to get the heating load.

 

[Agile]

I would always advise doing a heat loss calc.

The last thing you would want is for them to find the rad output is too low and no capacity in the boilers.

Have you added 2 kW for the hot water cylinder?

I would also be thinking of using two boilers.

Tony

 

[KevC1]

Thanks for all the replies.

Yes Agile the radiator output is too low, and i've advised the customer of this. However there has been £20000 spent on oak flooring which is now all fitted. So it's a case of tough luck if this turns out to be the case.

I'm going to fit 2 30kw viessmann system boilers.

 

[Agile]

Another potential problem is that the rads have already been fitted with expensive oak flooring underneath.

But presumably they have not been pressure tested!

I suggest you disclaim from ANY leaking or design faults in the radiator circuit.

Tony

 

[KevC1]

You're right none of the radiator pipework has been prssure tested. I have no idea why, as if it was me i'd definitely be testing it prior to an expensive floor being laid.

Anyway I have disclaimed against any pipework leaks on the existing work.

It's not a great way to go about doing a job, but in these economic times we have to make a living.

 

[Agile]

Even so it would be sensible to find some way to do a dry tightness test, perhaps with air at about 1 Bar?

Tony

 

[Biggles..]

Mods can we join this and 2 system boiler post so we don't get lost.

I'll add my worth to the other post

 

[muggles]

I'd do a whole house heat loss calculation, forget what the radiator output is. My reasoning is that even if the person who specced and installed the rads got it wrong, you can still turn round at the end of the day and say you've installed the correct size boiler(s) to heat the house. That way there can be absolutely no comeback to you if the house is cold - it's not your fault, as you have sized the boiler(s) correctly. It could well be that they have a change of heart and upgrade the rads, and if your installation doesn't have the capacity to deal with that then you're going to look a bit of a prat.

Go for two boilers at least. I'd be inclined to have them both on one circuit (albeit divided into zones), that way you can get at least some heat to the whole house if one goes down, as opposed to no heat in one part if you run two entirely separate systems.