1st Big Job Help please

[lordyjordy111]

Hi again

just got my first big job but am now questioning what I planned to do.

I am changing the boiler and rads but have a problem on the rad sizes...
the existing rads are like the ones in pic below

.

in one of the bedrooms for example they have a double panel version of this measuring 1030mm x 600mm which I was going to change to an 1000 x 600 p+.

However when i worked out the the btu's needed for the bedroom the new p+ far exceeded.

bedroom is 3m x 3m x 2.4 with double glazed window 1.9m2. I calculated 1852 BTU'S for the room but a p+ of this size pumps out 4589 btu's???

obviously I'm governed by the existing pipes on the length of the rad but would anyone just put a k1 in there

this scenario is repeated all over the house

 

[Doodlebug]

Just put in what the room needs, if a k1 is sufficient then do that. Doesn't matter if your a bit over but wouldn't oversize too much. Your not governed by the pipes, you can repipe can't you?

 

[lordyjordy111]

no not in every room she doesn't want me lifting the floors.....

just a bit wary of undersizing thats all.......

 

[Doodlebug]

Well do the calculations and then look for a radiator that will suit, best to be over than under and advise on trv's.

 

[acecharly]

I'd just change them like for like, how many rads are there? aslong as its not some mansion the boiler wont struggle.

 

[tamz]

For that size room your calcs are well over unless they live in a barn or you are sizing it to give 26º.
As said do your calcs and choose the most suitable rad. Bigger rads cost more money but on the upside they allow the boiler to be run at a lower temp. Customers however are generally stupid and want to feel the heat bouncing off the rad so they don't give a flying to that.
Just do what you think is right.

 

[lordyjordy111]

@acecharley

thats what I was thinking originally, but the old double panel ones aren't convectors so if it is a double panel original would you change to a double panel k2 or p+???

 

[lordyjordy111]

@tamz

i used an online calc how did you do yours???

 

[Billy Bob Bob]

@tamz

i used an online calc how did you do yours???

probably like me with a mears or the other method we use is experience

 

[acecharly]

Replace it with what fits mate, if your customer is placing conditions on changing the radiators such as not being able to lift floor boards theres not alot else you can do just make sure you charge her. Id use the p+/21 single cons they'l murder it.

As said above make sure you add in for TRV's mate.

 

[lordyjordy111]

ok gasman I did say it was my first big job......

where do you purchase a mears calc?

 

[lordyjordy111]

Replace it with what fits mate, if your customer is placing conditions on changing the radiators such as not being able to lift floor boards theres not alot else you can do just make sure you charge her. Id use the p+/21 single cons they'l murder it.

As said above make sure you add in for TRV's mate.

cheers will i did include trv's in quote

 

[tamz]

@tamz

i used an online calc how did you do yours???

I never did one but i know a room that size is just over a kw (depending on house type and exposure) before i count it. It is an age thing.

Get yourself the stars program or the myson heatloss calc or buy a mears here
MEAR'S CALCULATORS
or do it longhand.

 

[kay-jay]

You can find rad size calculators on the internet. If in doubt just swap like for like. As mentioned before custards like jumping hot rads. If old rads are imperial get yourself a couple of rad extensions just not the telescopic ones as the o'rings Will leak soon enough

Sent from my GT-I9100 using Tapatalk 2

 

[lordyjordy111]

ok lads thanks for the help.....

 

[Doodlebug]

ok lads thanks for the help.....

Have fun on your first big job mate and let us know how you get on.