Help me understand boiler stat and pump speed - use less gas

[oldskoo1]

I've got fed up reading the meter and I'm trying to set up the system to use as little gas as possible now our boiler is fixed.

It's an old ideal classic ff380 non condensing. 20 rads and a 15/60 pump serving a 5 bed 3 storey.

Heating is on from 6am to 11pm, wall stat auto adjusts the temp but averages 18c, it drops to 12c overnight.

What would save us money by using less gas.

1) boiler on 6 (max) at 82c - quicker heat up

2) boiler on 4 around 72c - less gas but longer heat up

We have a cylinder too set at 60c and also a very important factor pump speed.

What cycling is acceptable, I can't get my head around this. On speed 2 all rads are warm but boiler seems to cycle a little more, perhaps on for 7-10mins before stopping briefly allowing the pump to move more water.

Pump speed 3 seems to have less cycling but a lot noisier and potentially introducing air from the impeller and would it be moving water too fast to heat properly?

Currently have it on setting 4 and pump speed 2. But I'm curious if 6 max and pump speed 3 would save gas.

We need it on all day and temp can't go any lower. Trying to find the sweet spot of comfort v cost.

 

[ALEC1]

Insulation is the best way to save gas, then a modern condensing boiler with weather compensation such as a Viessmann vitodens 200

Tinkering with that old tat wont acheive much, and is a waste of time in my opinion..

 

[wannocks]

Tinkering with the pump speed on an old inefficient boiler will make little difference. Dont try setting the pump speed too low. Too slow will cause overheating and kettling in the boiler.

 

[diynoob]

Fiddling with pump speed and boiler temp won't save you much gas.

Use TRVs to reduce the temp in other rooms so you're mainly heating the space you are in. Also, add more insulation to your home.

A more efficient boiler would reduce your gas usage but would take a long time to see a return on investment in comparison to TRVs and insulation.

Reducing the time the boiler is on and reducing the room temp will of course save gas but you don't want to reduce the comfort level as you mentioned.

 

[Dan Robinson]

Short of changing the boiler and getting weather comp too... which will be expensive, but a definite long term saving...

The best thing as Alec said is invest in insulation.

After that, a programmabe room thermostat.

Then after that zoning the house.

Most expensive route - is a repipe, so forget that. Then Honeywell Evo with wireless rad valves.

However a more financially practical route is the adding of something like the iTemp programmable rad valves.

Obviously the idea being only heat the rooms you need at the times you need them - do your REALLY have to heat the WHOLE house all day?

Look at your KW consumption for the last year or two. Calculate a saving of 15 - 20%. Assume say a new boiler fitted is £2.5K. Now deduct that % figure you have from your projected bills for the next few years and see what the payback time is.

>6 years, probably not worth changing the boiler.
<6 years; consider the upgrade.

 

[ALEC1]

The problem with zoning is that unless the rooms are thermally insulated the heat goes to the coolest space...a basic law of thermodynamics...

and anyone who has lived in a flat will tell you that they know when people are up stairs or downstairs from the activity of their own boiler..

Zoning is easy to understand, but it wont neccesarily save you any energy over and above running the whole house at one temp...that said it depends on the house size...and there are a lot of variables..

best bet is a correctly sized boiler with TRVs on rooms you don't use turned low...

 

[Dan Robinson]

Theory and practice are two very disparate bed fellows Alec.

Trusty me on this.

I am as you know in a house that is zoned down to room level with Evo. Currently with only 3 rooms habitable, with no out of the ordinary insulation between them, I can say that it makes a bit difference internally.

Closing doors is a must though obviously .

 

[Boilerman2]

Unbelieveable!! the boiler is now fixed, and using Gas and now you want to turn it off to save Gas!! - a 5 Bed house is going to cost £££'s to heat as said good insulation and an "A" rated boiler combined with intellegent controls would be the way forward, but you will have to spend £££'s to acheive this

Pussying around with boiler stats and pump speeds will achieve NOTHING!!

 

[dcawkwell]

Wear a jumper and only heat the one room where you are
by some method. Not the central heating.
Have the heating on for a couple of hours in the morning
and a few hours in the evening.
That is it.

 

[oldskoo1]

Unbelieveable!! the boiler is now fixed, and using Gas and now you want to turn it off to save Gas!! - a 5 Bed house is going to cost £££'s to heat as said good insulation and an "A" rated boiler combined with intellegent controls would be the way forward, but you will have to spend £££'s to acheive this

Pussying around with boiler stats and pump speeds will achieve NOTHING!!

Yes, it is ironic but I'm the type of person that like things running optimally and efficiently. I changed both thermostats on my car recently because it wasn't getting up to temperature. You would never know the difference, the mpg is the same, the power the same but it will prevent premature dpf failure which will cost £1,400.

Just the way I am.

I don't like waste, this house doesn't cost a lot to heat. It might have 20 rads but its only costing around £135 - £170 per month in gas so far, nov and dec projected. I just want my system running efficiently. In the process I want to learn about it and I don't want to waste gas, I don't like waste.

I'm sure balancing the rads and matching the pump speed and stat controls must achieve something.

Since fixing my boiler and balancing the system I have noticed a dramatic change in even heat throughout the house, quicker warm up times (no surprise if you knew my previous problem) and less cycling now I set the stat to just below max and pump on 3.

I realised today the boiler stat doesn't control the input of gas volume it just tells the boiler when to shut off when it's reached the stat temperature. Setting it lower can cause cycling which can be inefficient. So setting it to nearly max and upping the pump speed must account for something as the boiler now only turns off twice, maybe 3 times during around 30-40mins of raising the temp 1c.

My parents had a new wb condensing boiler put in over a year ago. Like for like consumption (weather differences) you are only looking at a 4% saving. New boilers aren't magic so I'm not looking at swapping mine any time soon. Just would like to get mine running optimally after the previous house owners were running the system with the flow and return incorrectly a all lockshields fully open for the past 7 years

 

[Dan Robinson]

y parents had a new wb condensing boiler put in over a year ago. Like for like consumption (weather differences) you are only looking at a 4% saving.

It is not working properly/installed badly/used incorrectly.

Even with basic controls we regularly get customer saying they are getting 15 - 20% savings.