boiler Advice

paulmapp8306

Well, I think Im going to have a new boiler. My current one is an Ideal Classic RS50 (I have only been in the house 6 months and dont know the exact age) is quite old I believe (18-19 years?) and while supported isnt exactly efficient, and will need replacing in the next few years anyway - wont it?

It is a G type rated at 65% efficient which Im guessing was when new as well. Efficiency alone doesnt make it worth changing though (I dont think anyway, cost of replacement v savings? - someone put me right here if Im wrong) however its only an 18KW boiler.

Im having a new Kitchen and Bathroom in the next 6 months, and as part of that were having a decent sized towel rail replacing a dinky radiator in the bathroom, a larger kitchen radiator as its always cols in there, and a larger one in the main room - again quite cold as the current radiators struggle to keep the heat up in those two rooms, which are the main ones. I have calculated the total output of the new system and its not much below 18KW. On top of this theres a new large sealed tank going in, so I can have a mains fed shower and a P or L shaped bath (apparently our current tank doesnt hold enough water to fill one of those). So - all on all it makes sense to replace the boiler. Not least as the plumber is on site anyway (being paid daily by our main contractor) and we are having a power flush when the radiators/tank are replaced.

all that out of the way - I have no idea which boiler to go for. Its my first house so never had to do this before. Im considering either:

1. Valliant EcoTec Plus 630 system boiler
2. Worcester Greenstar CDi30 system boiler.

is either better than the other? the Worcester seems a touch cheaper. Are either BAD ideas? are there better? Help here is appreciated.

diywhynot

paulmapp8306 wrote: »

1. Valliant EcoTec Plus 630 system boiler
2. Worcester Greenstar CDi30 system boiler.

is either better than the other? the Worcester seems a touch cheaper. Are either BAD ideas? are there better? Help here is appreciated.

Based on the info provided by you both boilers will be oversized for your property. I'd recommend the Vaillant over the WB. Have you sought advice from a recommended RGI?

paulmapp8306

My installer is RGI registered, and said and, an either make is fine.

When I do a search for which boiler on various boiler manufacturer sites, they all point to a 28Kw or 30Kw boiler.

Its a 4 bed house with 17.5Kw worth of radiators, a 120 Ltr tank, one bathroom and one en-suit with shower, a kitchen and a UT room both with sinks. I would potentially need two sinks, a bath and a shower plus the heating on at one one time.

The current 18KW boiler struggles as it is. the heating water is getting cool by the time it hits the last radiator if there all on full on and theres three bigger ones to go in. I suspect a 24kw boiler may be enough, only just. no ro0m for any further expansion if needed and might struggle on a really cold day. 28Kw would be better but I cant find any decent makes (that i know of) that do 28Kw system boilers. Only Glo-Worm from what Ive found.

Both Worcester and valiant dont do 28Kw from what I can see. That said i might be wrong, hence wanting some advice.


that said, ive only looked at system boilers, not standard open vented ones (which the current on is, and which would work with a sealed system). Im also a firm believer of "too large rather than too small". Obviously from an economic POV there is a little saving in using something thats not too big, but i dont think (from a GAS useage perspective) theres much in it when using a sllightly too big boiler (as long as its not massively big).

paulmapp8306

Umm, doing some calculations a 30Kw might be too much. a 24Kw isMaybe this one then. probably enough?

Something like this the Vaillant Ecotec plus 624HE?
or the Worcester Greenstar 24i System

gas4you

Assuming your home gets nice and warm already with the existing boiler, I would say the Vaillant Ecotec Plus 618 will be adequate.

With new time controls, you would just need to set the HW to come on about 30 mins before the heating first thing in the morning.

This will be the only time you MAY need the full power of the boiler.

paulsad

Both decent choices - I installed a 30i at my last property - it was a 3 bed Victorian semi with high ceilings and the 30i was enough I'd say but only enough - I wouldn't have gone any smaller than that for that property anyway. So better to be on the safe side IMO.

paulmapp8306

gas4you wrote: »

Assuming your home gets nice and warm already with the existing boiler, I would say the Vaillant Ecotec Plus 618 will be adequate.

We have to set the radiators so either upstairs is warm and downstairs cool, or vica versa. At present downstairs is fine, the 3 bedrooms are OK (as cool is good) but the bathroom and spare room (my music room) is a little on the cold side. its just about useable as it is.

with the 3 more radiators to add (one T21 600mmx1000mm being replaced by a 600mm x 1400m T22, one 600x800 T21 replaced by a 700x800 T22 and one 400mm x 600mm replaced by a 600mm x 1200mm towel rail), the existing 18Kw isnt going to be up to it. Its really down to whether a 24kw will be enough when everythings in. If its borderline Id rather go bigger - to the 30Kw (Im assuming). if the 24kw would be fine then thats to one to get I guess.

the reasons for changing the Rads. the towel rail is obvious. the 700x600 T22 is going in the kitchen. it doesnt get as warm as the living room because weve converted a joining room to a UT room which doesnt have a Rad, and the new floor is stone which will be a little colder. The other is in the front room - we have sliding patio doors and the current radiator doesnt give enough heat to maintain the living room properly. it doesnt help its the last in the run so doesnt get piping with the current boiler, but even when it does when we turn upstairs rads off) its always a degree or so below where we want it in the winter.

cyclonebri1

diywhynot wrote: »

Based on the info provided by you both boilers will be oversized for your property. I'd recommend the Vaillant over the WB. Have you sought advice from a recommended RGI?

I know it's not the case here, but I'd be cautious about relying too much on the advice of a single RGI. They do tend to get better deals from some suppliers/manfs than others. More than 1 opinion reqd imho for an investment that will be with you possibly another decade or 2.;)


I am unsure if the efficiency of a boiler drops off if it isn't running near full capacity, 1 of the resident installers here may know?

diywhynot

paulmapp8306 wrote: »

Umm, doing some calculations a 30Kw might be too much. a 24Kw isMaybe this one then. probably enough?

Something like this the Vaillant Ecotec plus 624HE?
or the Worcester Greenstar 24i System

Your Ideal Classic RS50 has a maximum heating output of 14.7 kW. A RGI should do a Whole House Boiler sizing calculation.

diywhynot

cyclonebri1 wrote: »

I know it's not the case here, but I'd be cautious about relying too much on the advice of a single RGI. They do tend to get better deals from some suppliers/manfs than others. More than 1 opinion reqd imho for an investment that will be with you possibly another decade or 2.;)

Some RGIs won't put the effort into doing a proper calc. We don't get deals from any manufacturer but make a recommendation based on what is the best fit for the customer/property as well as our experience with the product (I can't speak for others.;))

diywhynot

paulmapp8306 wrote: »

We have to set the radiators so either upstairs is warm and downstairs cool, or vica versa. At present downstairs is fine, the 3 bedrooms are OK (as cool is good) but the bathroom and spare room (my music room) is a little on the cold side. its just about useable as it is.

with the 3 more radiators to add (one T21 600mmx1000mm being replaced by a 600mm x 1400m T22, one 600x800 T21 replaced by a 700x800 T22 and one 400mm x 600mm replaced by a 600mm x 1200mm towel rail), the existing 18Kw isnt going to be up to it. Its really down to whether a 24kw will be enough when everythings in. If its borderline Id rather go bigger - to the 30Kw (Im assuming). if the 24kw would be fine then thats to one to get I guess.

the reasons for changing the Rads. the towel rail is obvious. the 700x600 T22 is going in the kitchen. it doesnt get as warm as the living room because weve converted a joining room to a UT room which doesnt have a Rad, and the new floor is stone which will be a little colder. The other is in the front room - we have sliding patio doors and the current radiator doesnt give enough heat to maintain the living room properly. it doesnt help its the last in the run so doesnt get piping with the current boiler, but even when it does when we turn upstairs rads off) its always a degree or so below where we want it in the winter.

I suspect you have a circulation problem.