Gas Central Heating Installation Query

MGallo

I wondered if anyone can advise on the type of gas central heating installation that we need for a house we are renovating as we seem to be getting some conflicting advice. The house is on three levels with 5 bedrooms and 3 bathrooms and shower-room.

We have been advised to either have a 40 khw Alpha Flowsmart Gas Saver 50L Pack OR a 50 khw standard condensing boiler (commercial Potterton) with a 250 ltr pressurised hot water cylinder.

Does anyone have any thoughts on this as we are a bit lost!

Many thanks,

Mary-Anne

southcoastrgi

use something like this to work out the rad outputs you need, i would be very surprised if you need anywhere near the boiler output you have been advised, to have an unvented cylinder you need to have your flow & pressure tested to make sure it will be suitable

Mr_Ted

In accordance with "part L" a whole of house calculation should be used to calculate the required boiler sizing!
Unfortunately even know not all "experienced" installers comply with legislation?
Which is why so many installations are not always as they should be?

southcoastrgi

& if you use what i suggested & have a rad in every area which you would normally have then it will be a whole house calculation

Mr_Ted

Sorry "young" man but clearly you do not know the regulations according to part "L" as that calculation "whole of House" is based on property volume, not room by room"
Do ya wanna see my City and Guilds part L assessors certificate and the relevent course calculation assessment sheets!
"SAP" has many meanings but in this case "Standard Assessment Procedure"!

C_Mababejive

My initial thoughts are go for the HE boiler and cylinder option.

southcoastrgi

Mr_Ted wrote: »

Sorry "young" man but clearly you do not know the regulations according to part "L" as that calculation "whole of House" is based on property volume, not room by room"
Do ya wanna see my City and Guilds part L assessors certificate and the relevent course calculation assessment sheets!
"SAP" has many meanings but in this case "Standard Assessment Procedure"!

so you do a whole house vol calc, then the installer comes along & works out the rad sizes & outputs for the indivual rooms which is totally different from your whole house, so now the boiler is either too big or too small making your whole house calcs a total waste of time

Mr_Ted

Lets make it as simple as possible!

The OP is asking for options which will only be guesswork and he will eventually know he has to get a quote for his exact requirements, or should do!

As the installer You do as the legislation asks you to do, "SAP" and quote on the findings of that!
http://www.planningportal.gov.uk/uploads/br/BR_PDF_PTL_DOMHEAT.pdf

And of course, as everyone else does, huh, you notify the relevent authority of the/all works carried out with the relevent certification!

If you dont do this then you are currently carrying out work in contravention of the regulations!

You should also note, and as i have stated in the past, a FULL System UPGRADE is required, again in accordance with PART L

southcoastrgi

I don't really understand your point ?
Boilers must be A rated which is the only kind you can buy
Cylinders must be insulated with a label which the manifacturer does
Heating needs to be zoned
Timers are always installed
Room stats must be fitted to provide a boiler interlock
Fully pumped again you can't buy a gravity boiler
Reg the boiler with GS & they notify BC
etc etc

All of this is a standard install nothing special & certainly nothing that you have to inform BC for or pay someone to do a independant survey for.

however if you do want to use Mr T's route there is a simple form here that you can use, but i would still compaire it's findings with the rad outputs you need

Mr_Ted

Its all about sizing and efficiency which is why the regulation was brought in!
A "SAP" is to assess the optimum boiler size, and also is supposed to be submitted as proof of conformity!
Rads have to be sized in accordance with the type and size of boiler installed, ie a condensing boiler with rads sized to ensure low return temperatures so that the boiler does condense to achieve maximum efficiency!

If you size rads to determine the size of boiler required (the old way) then low return temperatures are unlikely other than on start up and the boiler will not condense (and modulate) as it should for maximum efficiency!
In comparison to the old method, rads need to be undersized to achieve low return temperatures!

An independant survey is not required as the installer(estimator) should be qualified to carry out the "SAP" as part of the quoting process!

There are of course other install element that should be conformed to in accordance with the regulation, pipe lagging, trv's, double control valves on cylinders(1 as a safety)!

MGallo

Thanks for all the information - I'll have a look through this tonight and hopefully work out a way forward.... I can't get over how many conflicting solutions I've been presented with by gas installers....

Will maybe be back with more questions later :-) Thanks again.

Mary-Anne