What size and make of boiler ?

[MattT]

Hi all,

I have a 5-bed, 4-bath house (1 master, 3 en-suite) plus a downstairs WC. It’s 270 sqm with 19 radiators. When the boiler was first fitted the house was 210 sqm, but was extended about 3 years ago and we bought it 16 months ago.

The boiler is an 8-year-old Vaillant Ecofit Pure 630 (30 kW). It’s always struggled to get heat to the last two radiators on the circuit. Most rads don’t have TRVs, and I assumed fitting them might help by pushing flow to the end of the system and perhaps a system clean.

Recently the boiler has started making noise. I suspect it needs cleaning, flushing and inhibitor, though there may also be a mechanical issue.

Online guidance seems to suggest a suitable replacement is a Vaillant EcoTEC Plus 35 kW or Worcester Bosch 8000+. I know calculators aren’t perfect compared to a proper survey, but does it sound like I need a larger boiler, or is the current one likely correctly sized and just in need of proper maintenance?

Thanks

 

[Wayners]

Sounds like you need to get radiators balanced.
You also need water inside to be clean with inhibitor.
Find a good local heating company to come and advise.

Oh. You can get booster pumps

 

[MNW67]

It also probably depends on how well the house in insulated. When was it built.

 

[MattT]

It also probably depends on how well the house in insulated. When was it built.

1930 house, cavity wall and about 150mm of insulation in the loft from memory

 

[MNW67]

Are you able to increase the power on the pump.

 

[MattT]

Are you able to increase the power on the pump.

I did do that about 9 months or so ago and worked to balance out the rads as suggested above, it seemed to be better in October but haven't had guests stay overnight in December. Been more distracted by the noise of the boiler which is somewhat noisy !

 

[Harry Bloomfield]

I did do that about 9 months or so ago and worked to balance out the rads as suggested above, it seemed to be better in October but haven't had guests stay overnight in December. Been more distracted by the noise of the boiler which is somewhat noisy !

What temperature is your room stat set to maintain, during the night?

 

[MattT]

What temperature is your room stat set to maintain, during the night?

The TRVs where we have them upstairs are normally on 3 i.e roughly 20c, we normally set upstairs to 20c until about 7pm and then leave it off apart from a little 30-40 min kick at 2am. That's when outside is approx 10c as it is now.

The house also has 2 zones for upstairs and downstairs central heating, so we don't really heat downstairs past 8.30/9pm unless it's very cold outside and downstairs is all TRVd.

I do normally try to heat downstairs separately to downstairs to boost performance, as we also have a 300L unvented cylinder and the heating performance drops when both upstairs and downstairs are on, then another knock when the water cylinder is being heated.