Another boiler question

carly

I have had a couple of Gas Safe registered installers round to quote for the replacement of central heating boiler. I do not want a combi boiler and both installers have agred that a 15kW boiler will be sufficient for the needs of my small houe. 8 rads. eg vaillant ecoTEC plus

I was expecting to upgrade the gas pipework from 15mm to 22 mm but one installer has said that this will NOT be necessary due to the small kW size and as it will not be a combi boiler . This surprised me.

I have also been told that I will need to have either a TRV or a room stat in my lounge as currently i have neither. Stat is currently in the hallway and all other rooms have TRVs.

Can anyone confirm these findings or give me a link so I can look up the appropriate legislation for myself.
Thanks

brig001

If you look in the Vaillant ecoTEC plus manual, you will see that the gas inlet is 15mm, so that should be fine.

I would probably move the thermostat and fit a TRV to the hall radiator, but a second choice would be a TRV on the lounge radiator.
A TRV can only improve the temperature control and is easy and cheap to fit while the system is drained. I don't know if it is a requirement to do it though.
HTH,
Brian.

carly

thanks very much, that is reassuring. We've never bothered with a TRV in the lounge because it's too flipping cold, faces north and the room is always the coldest in the house but it wouldnt be a big job to fit one

latecomer

If the room is always cold then I would check whether the radiator is of a sufficient size to heat the room.

carly

latecomer wrote: »

If the room is always cold then I would check whether the radiator is of a sufficient size to heat the room.

good point. will check

Canucklehead

Hi

The Vaillant 415 consumes gas at the rate of 1.61 m3 /h .
It would be reasonably safe to assume that the boiler to be removed would consume a similar amount ,but your installer would check /know this.
Your proposed installer has given you good advice.
You should have a TRV on each rad except in the room or area where the room stat is located.

Note to brig001.

Just because the inlet connection is 15mm does not mean it's ok to fit 15mm pipe.
The Ecotec 831 combi requires 3.3m3 /h of gas and has an inlet of 15mm.Run 15mm pipe to it and it will not work correctly.

GSR.

heating-eng

Canucklehead wrote: »

Hi

The Vaillant 415 consumes gas at the rate of 1.61 m3 /h .
It would be reasonably safe to assume that the boiler to be removed would consume a similar amount ,but your installer would check /know this.
Your proposed installer has given you good advice.
You should have a TRV on each rad except in the room or area where the room stat is located.

Note to brig001.

Just because the inlet connection is 15mm does not mean it's ok to fit 15mm pipe.
The Ecotec 831 combi requires 3.3m3 /h of gas and has an inlet of 15mm.Run 15mm pipe to it and it will not work correctly.

GSR.

it is always best to fit trv,s but you do not have to do it and there is nothing that says you do.

If the inlet to the boiler is 15mm then normally 15mm pipe will be ok as long as its not to far...your installer can check this to make sure..but you can normally run quite a bit of 15mm pipe on a 15kw boiler.
you are quoting a 831 combi this is totally different.

Canucklehead

Hi

I thought the post was rather obviously divided into two parts.

Perhaps you could get someone to explain it to you?


GSR.

gas4you

I will have to agree with canucklehead on the pipe sizing.

heating-eng

Canucklehead wrote: »

Hi

I thought the post was rather obviously divided into two parts.

Perhaps you could get someone to explain it to you?


GSR.

can you explain where it is divided ???
the post asks about a 15KW boiler from what i have read i might be wrong..

but 15kw only needs 15mm gas.. i used to train BG engineers on pipe sizing for many years so i no all about pipe sizing ..Thanks

ziggyman99

heating-eng wrote: »

can you explain where it is divided ???
the post asks about a 15KW boiler from what i have read i might be wrong..

but 15kw only needs 15mm gas.. i used to train BG engineers on pipe sizing for many years so i no all about pipe sizing ..Thanks

So a 15kW boiler is OK on 40m of 15mm pipe is it? ALL installations must be correctly sized for a working pressure of 19mb or higher. A blanket statement such as yours is completely incorrect and would be frowned upon by any Gas Safe inspector.

I'm new to gas which is why I probably do things correctly.