Condensing Boiler temprature

RazBurley

Lorian said:

That's Y plan. I look after three properties with Y plan. Always worth having a spare synchron motor in stock 

Are you saying you switch that switch on with a red light to heat the water? If so you are using very expensive electric immersion to heat your water. 

Somewhere you will have a programmer box with a display on it. That's what you need to be using to heat the water automatically using the gas boiler. Post a photo of it maybe.

Hi  no we don't use the swtich in cupboard for heating. We use the boiler controller which is in the kitchen and its the boiler which is used for hot water. See attched pic. Thanks 

Lorian

Ok so the maximum temperature you can heat your water to is the flow temperature of the boiler. I tend to run mine at around 60 flow (sitting on the fence on the legionella debate) and typically see return temps of 40-45c depending on which TRVs are shutting. 

FreeBear

Lorian said:

Ok so the maximum temperature you can heat your water to is the flow temperature of the boiler. I tend to run mine at around 60 flow (sitting on the fence on the legionella debate) and typically see return temps of 40-45c depending on which TRVs are shutting. 

With a return temperature of 40-45°C, that should push efficiency up to around 92%. Pretty good

RazBurley

FreeBear said:

RazBurley said: We are thinking  to put 1 more radiator in sitting room and 2 small radiators in colder part of house where we don't have any radiator. Do you guys think our boiler vaillant eco tech plus 418 is able to handle 3 more rads? At the moment we have 6 rads.

I think the Vaillant Ecotec 418 is rated at 18kW. Unless you have humongous radiators, it will have plenty of capacity for more.
Had 8 radiators of various sizes on a 12kW Baxi, and they worked just fine. It isn't the number of radiators, but their power output. So total up the kW ratings for all the existing radiators and then add on the extra for the new radiators.

The label on boiler has 18.6kw and 18.9kw so I think our boiler is 18.9kw, so it should be ok to add 3 extra rads and upgrade 2 from single panel to double panel? 

RazBurley

Hi All,

An update.

Plz see attached pic

Today i learned that inspite having two  control dial on boiler its actually heating control dial which sets the water and heating temp so if i low the heating water temp to 60 degree hot water will also be on 60 degree. The control with tap sign ,  if we rotate it it cahnges the numbers on the screen but does not do anything unless we fully turn it down then it shuts the hot water. So its only one control for both heating and water temp. Today morning I noticed that water was not as hot as it normally used tobe and i think it was because of me putting heating temp to 60. So i am going to keep it 68 and lowring the flow temp only possible if i do it manually every time heating is turned  on.

Can someone plz explain what the buttons with  - and + sign and a ladder sign underneath does?


Thank you

Lorian

That's what Ive been trying to say. You have a boiler that could be a combi or a system boiler but it is working as a system boiler as you have Y plan and a tank. The hot water controls on the boiler don't come in to play. If the diverter were in use in the boiler you would have hot water priority rather than Y plan but we can see you have a three port valve so it's not.

It's still possible 60c flow could be enough but you may need the program for the tank to come on for longer or at a more suitable time. When does the programmer say the water is set to heat and do how long.

It's hard to get all this right without knowing what your tank thermostat is set to (it's hiding under the red jacket somewhere DON'T pull it off)

Also helps greatly if you have a cheap led thermometer with probe where you can put the probe down the side of the tank thermostat so you have a display of the water temperature on the tank (well in one layer that's another topic)

RazBurley

UPDATE:

Today boiler was on for 7 hours of which 2.5 hours at full flow temp of 68 degree which includes 1 hour to heat the water at full temp. After hot water timing i put the flow temp down to 60 degree for rest 4.5 hours. The resuts are as below

Total gas used: 5 cubic meter
55.53kwh, cost £3.50 approx.

more updates to follow

FreeBear

That is working out to 7.9kW per hour - What was the outside temperature, and what are you heating the house to ?

For comparison, my heating had been on for just under 2 hours and warmed the place up to 19°C whist it has been -4°C to 0°C outside (used 11kWh of gas with a flow temp of 42°C to 56°C). But sun was shining, so I benefited from quite a bit of solar gain, plus I lit the stove around 16:00.

RazBurley

FreeBear said:

That is working out to 7.9kW per hour - What was the outside temperature, and what are you heating the house to ?

For comparison, my heating had been on for just under 2 hours and warmed the place up to 19°C whist it has been -4°C to 0°C outside (used 11kWh of gas with a flow temp of 42°C to 56°C). But sun was shining, so I benefited from quite a bit of solar gain, plus I lit the stove around 16:00.

Outside temp was 0 i think and i was heating house to 18 degree.

Yours is doing good. What kind of house you live in? Our house is 2bed mid tarrace and i think built around 1955. Our house takes long to get warm probably loosing heat. I don't know how to check heat loss and make the house more energy efficient. Our epc rating is C which i believe is wrong. It must be D or over. Our boiler was made in march 2010 i think. 

FreeBear

RazBurley said:

FreeBear said:

That is working out to 7.9kW per hour - What was the outside temperature, and what are you heating the house to ?

For comparison, my heating had been on for just under 2 hours and warmed the place up to 19°C whist it has been -4°C to 0°C outside (used 11kWh of gas with a flow temp of 42°C to 56°C). But sun was shining, so I benefited from quite a bit of solar gain, plus I lit the stove around 16:00.

Outside temp was 0 i think and i was heating house to 18 degree.

Yours is doing good. What kind of house you live in? Our house is 2bed mid tarrace and i think built around 1955. Our house takes long to get warm probably loosing heat. I don't know how to check heat loss and make the house more energy efficient. Our epc rating is C which i believe is wrong. It must be D or over. Our boiler was made in march 2010 i think. 

Late 1920s bay fronted 3 bed semi (fairly typical inter-war build). Ground floor is cavity construction and the upper half solid brick (~240mm thick) and rendered. Loft has 300-400mm of insulation, and about half of the solid walls have ~75mm of Celotex on the inside (as each room gets renovated, the walls are insulated). New uPVC windows & doors all round (apart from the kitchen). The sealed units in the old windows had blown, didn't close properly, and were rotting away in places (mid 1970s DG replacements). Didn't help that they were badly fitted and there had always been cold draughts coming in around the sides. Spent quite a bit of money over the last few years... Still struggling to heat the (small) kitchen despite having ~3kW of radiator in there....

Low cost improvements that you could make is put more loft insulation down - Current recommendation is 270-300mm. Go round each room and plug all the cold draughts (incense sticks can help to track them down). If you have timber floors on the ground floor, there is often a gap at the bottom of the skirting. Plugging this gap can make a surprising difference. If/when you replace carpets downstairs, put down a layer of 5mm woodfibre underlay (the stuff sold for laminate flooring). Whilst it won't provide much in the way of insulation, it will stop draughts coming up between floorboards (or if you have concrete, cut heat loss a little). Plugging any unused fireplaces with a Chimney Sheep (other products available) could cut heat losses by up to 2kW.

Fitting a programmable thermostat that allows for different temperatures throughout the day/week could potentially save you up to 15% (in reality, more like 5%). If you can find one that talks eBUS (fairly sure that the 2010 EcoTec supports it, but do check first), you can make better use of the modulation and maybe even do priority domestic hot water - PDHW automatically increases flow temperature when heating the tank, and drops back down for just heating. Might be worth having a chat with Vaillant and see what they recommend.

As for heat loss - I use the Stelrad online calculator - https://www.stelrad.com/basic-heat-loss-calculator/ - Good enough to see if your radiators are big enough. For a more detailed analysis, Heat Punk could be used, but it is probably over the top unless you are contemplating installing a heat pump.