efficiency of vokera 16e

phelixoflaherty

Have this boiler and am wondering if it makes any difference to heat water and house at the same time or to use them separately.

Froststop

phelixoflaherty wrote: »

Have this boiler and am wondering if it makes any difference to heat water and house at the same time or to use them separately.

Same time IMO would be more efficient. While heating rads, water will heat also. Why run separately?

phelixoflaherty

Two channels.

One for heating

one for hot water

Froststop

phelixoflaherty wrote: »

Two channels.

One for heating

one for hot water

I would heat both together when you can, saves gas. If using the heating, let it boost hot water also. Save you having to run it later again when heating is off.
If you don't need the heating i.e in summer, and need hot water then you can use it for hot water only.

DGOBS

Why would heating both together save gas? Defies all logic mate, if you don't need hot water, don't heat it.

Froststop

DGOBS wrote: »

Why would heating both together save gas? Defies all logic mate, if you don't need hot water, don't heat it.

Give it a boost! Why would you drive from Dublin to Cork with 4 people in the car and go back up for a fifth person? You might loose 25% efficiency or more, both it saves loosing more in the long run. Think about it!

Are you saying if it takes 2hrs to heat a system to room temp and then, later run boiler for an hour to heat water? When it could all be done in 2 1/4 - 2 1/2 hrs it won't save fuel/gas? I think your way defies logic mate!!

DGOBS

So to zone heating is pointless, just heat your cylinder if you want hit water or not and that saves energy.

I am wrong. So is everyone else involved in energy conservation, and part L of the building regulations.

Froststop

DGOBS wrote: »

So to zone heating is pointless, just heat your cylinder if you want hit water or not and that saves energy.

I am wrong. So is everyone else involved in energy conservation, and part L of the building regulations.

Zoning is to offer the use of gas heating to heat hot water in summer as it costs the same per KW as an immersion because the KWH's is roughly same. In Winter if you heat both together, you might loose efficiency but you should save 15-20 mins on running time of the boiler, thus saving gas. There's a lot on paper as per regs but it's BS on site.
We use the following to calculate heating requirements for hot water: Litres x Delta T x 0.001166 i.e. 100lts x 40 x 0.001166= 4.664KW required to heat 100 ltrs at 100% efficiency to heat to 40 degrees.
If you compare that to oil:
100 X 40 x 0.001166 = 4.664Kw
Now we have to convert that to ltrs so / by 10= 0.4664
Now calculate the cost of 4.664 KW per gas/elec prices and compare to the cost of a litre of oil.
4.664 x 0.17 = 0.79 (€0.79 per 100 Ltrs)
0.4664 x .91 = 0.42 (0.42 per 100 Ltrs)
Yet the regs tell us gas is cheaper. Why BG a Gov/semi state company say so! IMO

DGOBS

Heating water you don't want or need is waste whatever way you cut it, it doesn't heat the water for free no matter what calculations you use, heat on demand

I don't see the point in comparing fuels here as it's not what we are talking about.

Zoning isn't just a winter/summer option, it's about time and temperature and interlock for conservation of energy.

Froststop

DGOBS wrote: »

Heating water you don't want or need is waste whatever way you cut it, it doesn't heat the water for free no matter what calculations you use, heat on demand

I don't see the point in comparing fuels here as it's not what we are talking about.

Well I guess it's down to what I posted before regarding travelling from Dublin to cork! Why take 4 and go back for the fifth if the fifth can be taken the first time.

Your not wasting if your cylinder is up to scratch, it will store until needed with little heat loss.

DGOBS

Problem is the majority of cylinders aren't, and as it's a 6-10 year old Mynute E my guess it that cylinder isn't highly insulated

The Dublin to Cork analogy is not quite correct either.
Would be better to compare a kettle, why not fill it to the top when boiler the water for a pot of tea, just in case you need another cup when your finished, it may or may not be still warm, eitherway it just cost you energy to heat what you didn't need.
(Or in your case, poor number 5 passenger didn't want or need to go to Cork but you used extra petrol to get him there)

Froststop

DGOBS wrote: »

Problem is the majority of cylinders aren't, and as it's a 6-10 year old Mynute E my guess it that cylinder isn't highly insulated

The Dublin to Cork analogy is not quite correct either.
Would be better to compare a kettle, why not fill it to the top when boiler the water for a pot of tea, just in case you need another cup when your finished, it may or may not be still warm, eitherway it just cost you energy to heat what you didn't need.
(Or in your case, poor number 5 passenger didn't want or need to go to Cork but you used extra petrol to get him there)

The kettle won't hold the heat! No matter what type of cylinder is fitted the calculations remain the same. It's down to insulation on the cylinder when heating & after it's heated to save money. You'd be surprised, the majority of cylinders in homes we call to are up to standard, a lot with solar cylinders and no solar fitted. At the end of the day you need to get the temp up and then hold it for as long as possible!

shane0007

Gee whizz guys, I'm standing here on the side of the road, freezing my nuts off, it's raining, I'm hungry & this car keeps whizzing past me full of guys. It looks like there's a party going on in it & it won't stop for me....

Froststop

shane0007 wrote: »

Gee whizz guys, I'm standing here on the side of the road, freezing my nuts off, it's raining, I'm hungry & this car keeps whizzing past me full of guys. It looks like there's a party going on in it & it won't stop for me....

Haha Shane you must be the fifth guy!

Froststop

Shane0007 What's your opinion? I'm sure you'll sort this out, you might explain it better than me.

shane0007

Froststop wrote: »

Shane0007 What's your opinion? I'm sure you'll sort this out, you might explain it better than me.

I'm afraid I'm with DGOBS on this. What you are doing is just keeping up with the heat loss of the cylinder. The average insulated cylinder loses approx 30C of water temp in a 24 hour period. Copper is a very good conductor of heat.

Time & temp control is always best. Heat where you want it, when you want it would generally save approx 30% per annum.
So once the HW is satisfied, the rads will heat quicker, the room stat will be satisfied quicker & the boiler will be switched off electrically.
To test, switch off the cylinder balancing valve & see how much quicker the rads react.
Zoning is just not about being able to heat water only during the summer. That's what a summer valve is for.

Froststop

shane0007 wrote: »

I'm afraid I'm with DGOBS on this. What you are doing is just keeping up with the heat loss of the cylinder. The average insulated cylinder loses approx 30C of water temp in a 24 hour period. Copper is a very good conductor of heat.

Time & temp control is always best. Heat where you want it, when you want it would generally save approx 30% per annum.
So once the HW is satisfied, the rads will heat quicker, the room stat will be satisfied quicker & the boiler will be switched off electrically.
To test, switch off the cylinder balancing valve & see how much quicker the rads react.
Zoning is just not about being able to heat water only during the summer. That's what a summer valve is for.

Are you saying give the hot water priority and when it's up to temp it switches over to rads.

I think I'd have to agree to disagree! You better start walking back to Cork Shane lol!

However we may have stumbled onto something here. If a plumber installs a system with the intention to operate in a certain way and the electrician wires it his own way, are we fighting a loosing battle?
I plumbed a house and there was supposed to be three circuits, hot water, upstairs and downstairs, rads controlled by room stats & hot water by the cylinder stat. A few years later I was called back as one of the zone valves packed up. I discovered that the electrician wired the valves directly off the time clock and didn't fit any room stats as well as not connecting the hot water zone valve off the cylinder stat.

shane0007

That's nothing to do with it. I am only referring to a system that is wired as per building regs & as per MI's.

It does not give priority to hot water unless it is wired as a W Plan. Most are only S Plan. Once hw is satisfied, it will deliver more heat & kw to the heating.

Irish Steve

Froststop wrote: »

However we may have stumbled onto something here. If a plumber installs a system with the intention to operate in a certain way and the electrician wires it his own way, are we fighting a loosing battle?
I plumbed a house and there was supposed to be three circuits, hot water, upstairs and downstairs, rads controlled by room stats & hot water by the cylinder stat. A few years later I was called back as one of the zone valves packed up. I discovered that the electrician wired the valves directly off the time clock and didn't fit any room stats as well as not connecting the hot water zone valve off the cylinder stat.

Been getting dogs abuse recently over in Electrics in a discussion about incompetent electricians, and here we are, second thread in 24 hours about electrician not doing what was required.

I had to wire up my own heating in 1990 when the spark walked away half way through the job because he couldn't cope with wiring up a Randall cable management centre panel in the hot press, probably because he was using 1.5 solid, and the terminals in the panel were'nt big enough to take more than 1 wire that size. 3 timeclocks, 3 MV's, a tanks stat, the boiler and 2 pumps meant quite a few wires arriving back at the wiring centre. What has proved very useful over the years has been a couple of 230v time recording hour meters, one on the main incoming supply to the boiler, the other on the burner side of the boiler stat, we get total running hours and burner running hours that way, and it's a lot easier to read a clock than to try to work out what oil is left in the tank by dipping it, and hours to litres is very easy if you know the jet size.

Re heating hot water or not, the main issue is how soon the hot water will be needed, and how good the insulation on the cylinder and boiler is.

If the hot water is needed relatively soon, (within 12 hours,) and the heating won't be on again before it's needed, there is probably an advantage in heating the 2 together, in that as well as having to heat the water, if the boiler has been off for a number of hours, it has to be brought back up to temperature as well, if it's already up to temperature, then topping off the water at the same time will be cheaper than firing the boiler again just to heat the hot water.

If the tank is not properly insulated, (spray on foam jacket is best), then all bets are off, the tie on red things are about as much use as a chocolate tea pot, unless you have 2 of them on there, and spent a number of hours fitting them, if there's only one, sort of fitted to most of the cylinder, then the losses from the tank will mean it may well be cheaper to take the hit on starting the boiler again, as that will need less than what's been lost from the hot water in the interim period.

Froststop

Irish Steve wrote: »

Been getting dogs abuse recently over in Electrics in a discussion about incompetent electricians, and here we are, second thread in 24 hours about electrician not doing what was required.

I had to wire up my own heating in 1990 when the spark walked away half way through the job because he couldn't cope with wiring up a Randall cable management centre panel in the hot press, probably because he was using 1.5 solid, and the terminals in the panel were'nt big enough to take more than 1 wire that size. 3 timeclocks, 3 MV's, a tanks stat, the boiler and 2 pumps meant quite a few wires arriving back at the wiring centre. What has proved very useful over the years has been a couple of 230v time recording hour meters, one on the main incoming supply to the boiler, the other on the burner side of the boiler stat, we get total running hours and burner running hours that way, and it's a lot easier to read a clock than to try to work out what oil is left in the tank by dipping it, and hours to litres is very easy if you know the jet size.

There is a system which can be set up on line with AMR system that can be used for that. It can read the litres pumped until full working temp, F&R temp, oil consumption and elec consumption, all plotted on a graph automatically in real time to work out actual running cost. It's also being used to monitor hot water cylinders for sizing commercial solar systems.

Irish Steve wrote: »

Re heating hot water or not, the main issue is how soon the hot water will be needed, and how good the insulation on the cylinder and boiler is.

I would be thinking the same, a lot of **** on paper works in theory but not on site.

Irish Steve wrote: »

If the hot water is needed relatively soon, (within 12 hours,) and the heating won't be on again before it's needed, there is probably an advantage in heating the 2 together, in that as well as having to heat the water, if the boiler has been off for a number of hours, it has to be brought back up to temperature as well, if it's already up to temperature, then topping off the water at the same time will be cheaper than firing the boiler again just to heat the hot water.

I agree it depends on the situation.

Irish Steve wrote: »

If the tank is not properly insulated, (spray on foam jacket is best), then all bets are off, the tie on red things are about as much use as a chocolate tea pot, unless you have 2 of them on there, and spent a number of hours fitting them, if there's only one, sort of fitted to most of the cylinder, then the losses from the tank will mean it may well be cheaper to take the hit on starting the boiler again, as that will need less than what's been lost from the hot water in the interim period.

I'd have to agree, there's not much point in plumbers going to the trouble of designing and installing systems if the electrician can feck the lot in one swoop. I have had arguments over wiring in the past as most electrician's just want to get it powered and get paid, then out the gap. All the modern systems & reg's in the world are a waste of time if the electrician takes short cuts. The other problem is most people won't pay for a modern system and will take the cheapest route.

shane0007

What you will find though is RGI's who are GID certified do their own wiring of heating systems as it is a module of their training.