Which is an adequate Boiler ?

loafclover

I'm in desperate need of help and advise from a professional please.

I'm about to get Central Heating done in my house and really dont know how to work out which is an adequate boiler to buy as the one recommended by my contractor seems that its not the right capacity.

Work is being carried out by a CIPHE/GAS SAFE REGISTER contractor but I am way confused on his recommendation about what boiler to choose and what pipes (copper or plastic) to use for central Heating piping.

I am installing a MegaFlo system instead of Combi system. I have 4 bed room house and details are as follows:-

4 x RADS in each room - roughly 4000 BTU each (16000 BTUs)
1 x RAD in Loft - 4000 BTU
3 Towel Rads - 1800 BTU each ( 5400 BTUs)
2 x RADS in Living Room - 4500 BTU each (9000 BTUs)
1 x RAD Hallway 3500 BTU

In total I have 11 RADS which totals to 37,900 BTUs. He has recommended that the adequate boiler size for my property will be 24 KW and the boiler he has recommended is Vaillant ECO Tech Plus 624. I am worried that this is under capacity according to my requirements as I have spokent to few people and pretty much they recommend that I need a 37 KW boiler (126000 + BTU) and have advised that I should go for Vaillant ECo Tech Plus 637.

I already have a Santon Premier Plus - Unvented Hot Water System with 250 litres capacity cylinder/tank installed.

Reading from Vaillant website it seems that using Vaillant accessories with its system may be energy efficient but then again its Vaillant speaking volumes of themselves. :rotfl:

1. Vaillant Digital Room stat.
2. Vaillant 7 day programmer.
3. Vaillant Wireless Weather Compensator

I am thinking of using Weather Compensator (Now whether I should go for wireless one or wired one I dont know. Being a numb nut I think if I go for wireless one it will help me save money on installation cost as there will be less wires and configuration to do. But then again I could be wrong.)

I'm not too sure whether I have the right combination of accessories listed above or not. I am not too sure what to do and am getting soo confused that I keep going in circles as cant seem to get the correct advice from any where unfortunately hence this thread.

I would be grateful for any ones advice and if they can please point me in the right direction. (As with out a shadow of a doubt they will have more experience gained from practical and installation side of things.)

Any questions then please feel free to ask.

Many Thanks.

bengalknights

If its any help i have a a close to 40 year old boiler that pumps out 86000 btu to 14 rads most medium to large size so on that basis i would say the modern equivalent would probably be 28kwh to ensure its not underpowered but most boilers these days are far more efficient so if its only powering radiators then 24kw is probably right.

gas4you

From your figures I would go for a 15Kw boiler, or if you want to play safe and 18Kw.

Why do you want to have a 37Kw boiler heating a 12 Kw rad system?

Where do you think the extra 25Kw of heat can be used?

loafclover

thank you for getting back to me.

40 year old boiler is pretty amazing and the fact that its has lived through four decades. :T

Gas4you:- I forgot to add that the Boiler will also be providing hot water system for the house so its not just central heating. It's a Santon Premier Plus - Unvented Hot Water System with 250 litres capacity cylinder/tank already installed which currently runs on Electric to provide hot water to the house.

warmgas

For an unvented cylinder you should allow between 3-4kw. So with your heating (11kw) and hot water (4kw) you would require a 15kw boiler. To play it safe the next size up of vaillant boiler would be the 618. Ignore the people who suggested a 637.

gas4you

I also allowed the same for the Santon.

I always set my customers up so the HW comes on 30 mins before heating in the morning. That way you get the full power of the boiler to heat the santon, then the full power to heat the rads up.

Usually first thing on a cold morning is the only time a boiler will need its full output.

loafclover

First of all please accept my apologies for late reply and secondly for duplicating posts. Being a first time poster & lack of understanding has lead to this duplication but thanks once again for your help. I really do appreciate it. I dont know how to merge them and perhaps if MODS can that would be great. : )

One of the kind member Canucklehead
of the forum pointed me out to HHIC website - which outlines what an individual can expect in a quote. I wanted to add the link to my post but got warned that :- Sorry as I'm a new user I am not allowed to post with links. This is done to stop spammers clogging up the site. Please edit your message below to continue.... which is understandable.

Thanks once again for your advice. It really has helped and I salute you all. I'll tell you the reason why I opted for a salute...


The following the extract from the email that company replied to:- (My question in Blue BOLD)

From the conversations we had about the central heating piping I remember being told that you would advise plastic pipes are they are durable. I have my reservations for that as they might not be as feasible for me and I would be more comfortable with using copper piping instead around the house.

· Regarding piping materials, I and most engineers not obliged to discuss technical details with the customer because we are professionally responsible to maintain the quality and standard of our job, having said that I always mention to all customers before reaching an agreement details which could effect costs to give fairer price. regarding plastic pipes I can assure you that they are recommended for heating systems because they are heat efficient, quite, don't lose heat and installation would have less connection because you can get up to 50 meters pipe so they have less possibility of leaks, also they don't get rusty.

I did some digging around on Vaillant website. I found some interesting accessories that can be used with their EcoTech boiler systems. Like:-

1. Weather compensator
2. VRT 30 – Room Thermostat
3. Timeswitch 140 7/day timer which can also be used with VR 65 Control Centre ?

In their quote they suggested using Honeywell timer and vice versa. I was wondering is there any reason why they cant use Vaillant accessories ? The companies engineer reply is below:-

From my experience system should be kept simple and not complicated therefore in my installation I intend to use reliable controls like Haneywell and not fancy ones to make sure you wont be out of heating because a (high tec) digital programmer fail to respond because of some sort of interference of internet or radio wave and trust me alot of customers ask me to replace those with common and simple controls


Their reply was not some how convincing and in my experience thats usually comes from a person who either has limited understanding of the technology and or lack of experience of installation, but I could be wrong and hence am on a forum trying to gather information from more experienced individuals out there like your selves.

I was wondering if indeed vaillant accessories are too complicated and from a practical point of view - do they cause more agony then comfort ? i.e. keep breaking down etc etc ?

latecomer

loafclover wrote: »

also they don't get rusty.

Copper doesn't rust

To be fair, he may have a point regarding fancy electronic controls but in that case why doesn't he still fit mechanical timers?

gas4you

I'm a bit rusty on what controls Vaillant need these days, as I won't fit them anymore, but I think for WC you will need the VRC430 and possibly the VR81 control unit.

Canucklehead's husband fits Vaillant, so perhaps he/she will be able to advise you better.