Improvements for an old oil system

potts8

Hi,

We have just moved house and gone from a gas combi approx bill of £40 a month to an old oil system which so far seems to be costing us around £180 a month(around 100 litres a week)! :eek:

It's a very old Trianco TRO which has had it's burner replaced back in 2009 I think.
I believe it is pump fed CH and gravity DHW. the programmer(Salus RT500) only seems to control the CH so water is heated 24hrs a day.

There is no stat on the hot water cylinder so I assume this is heated up to the stat on the boiler. Currently set to 3 on a scale of 1-6.

The room stat is set to no more than 18 degrees and roughly has the following set:

06:30: 17
08:00: 15
15:00: 17
22:00: 14
23:00: 10

Based on our usage the consumption seems ridiculously high and I can only assume it is down to the hot water being on all day. I have checked what I can for leaks and nothing is noticeable however the line does go under a conservatory so I do lose sight of it.

House is 4 bed detached.

Do these numbers seem normal to any of you, is it to be expected?

I did just have the boiler serviced and the net efficiency to my surprise was rated at approx 92% which seems hard to believe.


What would be the next steps for me to improve this system?

I assume the first thing any plumber would recommend would be a new boiler but how much of an improvement would be had by being able to control when the water is on/off and a stat on the tank, assuming all of that is possible?

Ebe_Scrooge

I'm not sure how much specific advice I can offer, as I'm no expert on the technicalities of heating system. But for what it's worth, here are my thoughts.


Firstly, make sure your hot water tank is insulated to within an inch of it's life. If the tank is very old, you may even want to consider replacing it with a new one that comes pre-fitted with the latest standard of insulation. Obviously you'd need to weigh up the cost of this against any potential savings. A cheaper option may well be to just buy a standard tank jacket from B&Q or wherever, and add that to whatever insulation is already there. The point being, if the tank is properly insulated then the fact that the water heating is on permanently shouldn't be the end of the world - once it's up to temperature, it should retain the heat for many hours, and the boiler won't need to fire up very often to maintain the heat. Obviously a better solution would be to ask a heating engineer about fitting an upgraded controller - but again, it comes down to cost vs benefit.


Don't forget about insulating the house - loft, walls etc. Loft insulation, in particular, is very cheap and easy to install, and will make a big difference to your bills. Cavity wall insulation would be the next thing to look at (if your property has cavity walls). Finally, double-glazing - although this is expensive, and would take many years to pay for itself in terms of fuel savings.


In terms of your oil usage, I've just had a quick look at my own spreadsheet. Averaging over the last 10 years, I reckon my average is 43 litres per week - 5 bed detached in Scotland, fairly modern with good insulation etc. Now, that's averaged over the whole year - I reckon at this time of year I get through easily twice as much as I do in the summer, if not more. So, your figure of 100 litres per week at this time of year is perhaps not so unusual.


But like I say, your first job needs to be insulation. Assuming the boiler has been regularly serviced, and has no faults, I wouldn't be in a rush to change it. Yes, you may see a small increase in efficiency, but it'll take years to recoup the cost.


Hope this helps.

matelodave

Firstly is your system a two or four pipe system. ie are their two pipes going to the hotwater tank from the boiler and circulating the water by gravity and two going to the radiators from the boiler. Or has it got just two pipes from the boiler which feed the heating and hot water via a motorised valve.

When you established that you can look at ways of trying to improve the controls. I'm guessing that you've got a programmable stat for the heating but it would help if you had your hot water timed and controlled by a tank stat as well, rather than just the boiler stat.
It's fairly easy if you've got a motorised valve, not so easy but possible if you've got gravity circulation. I suspect that your room stat just controls the pump and the boiler just cooks away for 24 hour keeping hot

If you've got gravity, then a motorised valve in the return, controlled by a tank stat and timer would shut off the hot water when the tank was hot enough and an auxiliary contact in the valve would fire the boiler when the tank called for heat. Likewise a motorised valve in the heating circuit with an aux cantact to run the pump and fire the boiler would ensure that the boiler only heated when necessary.

I did all that when I had a gas boiler with garvity hot water and it made a big difference to the amount of gas being consumed, We also found that we lost a lot of heat from the hot water when the boiler was off due to reverse circulation back through the boiler, not helped by long runs of 22mm pipe under the floorboards - the motorsied valve prevented that as well.

As Ebe says, make sure you've got plenty of insulation over and around your hot water tank - two jackets are better than one and if you've got gravity circulation then insulate the pipes between the boiler and the tank to minimise heat loss.

potts8

Thanks for all of the info so far.
There are 4 pipes from the boiler, two on each side.
The tank has a two jackets on which one of them we have just purchased.

None of the pipes appear to be insulated though so that'll be one of my next steps.
There is some insulation in the loft but I'm not 100% sure of the depth so I'll check that out along with cavity wall ins.

Logically the next step I had in mind was getting some kind of control on the water heating. Any ideas on expected costs that may entail on a system like this?

matelodave

It all depends on whether you've got to get a plumber or you can do it yourself.
It's not eversso difficult if there's room for the valves and you are capable of plumbing, there's also the wiring to take into consideration so you need to be fairly competent.

Take note though, any valve on the hotwater tank must be on the return side to ensure that the vent and overflow to the loft tank aren't shut off when the valve closes.

potts8

Its not something that I would be doing myself tbh. I'd be getting a plumber out.
Would the cost of adding the heating controls pay for itself? I assume it would but I'm just surprised the previous owners have never done it.

Here are the photos of the boiler at either side, I assume it shouldn't be an issue to add the valves in this location?

https://imgur.com/a/nBXRl
https://imgur.com/a/jPVDM

Any ideas on what a ballpark figure could be?

matelodave

no, it's years since I did it

The valves are about £45 each*, a tank stat is around £20 (all from Screwfix), add a timer and labour and I suspect you wont get a lot of change out of £200. You need to get a couple of quotes.

edit: or more if the pipes are 28mm which is what they look like in the piccies

G_M

Do you know when the boiler was last serviced? If you don't know, or it was some years ago, then find a local OFTEC engineer who is also a plumber/central heating chap.

Get the boiler serviced and also get advice on the efficiency/reliability f the boiler. Some can go on for donkey's years and not be worth replacing. Others not.

Then get him to advise on the system, and replace the programmer to control both heating and hot water tank, and install a tank thermostat.

As others have said, insulate. Whatever the level of insulation in the loft, add another layer. However many jackets on the tank, add another. Any bare hot pipes (especially under floorboards or in the attic) put on pipe insulation.

(oh and get the oil tank checked too or do it yourself.)

enator

potts8 wrote: »

I have checked what I can for leaks and nothing is noticeable however the line does go under a conservatory so I do lose sight of it.

I would be concerned about this and you may want to look at having a new oil line installed. We had a leak of oil against an outside wall, and had to claim on the house insurance as it was so expensive to remedy - a leak under a conservatory would be extremely serious and extremely expensive. Below is an extract about who has to be involved if there is a leak;

Depending on the situation there are a number of organisations which could be involved in the event of a heating oil spill, including:

• the local authority (council);
• Health Protection Agency;
• insurance companies;
• Environment Agency;
• water company;
• environmental consultants; and
• sampling or remediation contractors.

Bit of a nightmare to be honest.

potts8

I've just had a quote in to convert to a fully pumped system with a stat on the HW cylinder and a Nest installed all for £1200.
It was a bit more than I expected tbh, I'm awaiting one more quote to come in so I'm eager to see how that compares.

Richmc

I see your boiler is located in some kind of "out house" so insulating ALL the pipe work is a must. regarding the hot water, when do you actually need the hot water, if it's mainly for a couple of showers in the morning and a bit of washing up then you NEED a timer, all it needs to be on for is for an hour just before you need it, you MUST get a tank stat, I've found that my set up of having the water heating coming on at 6.00am for one hour heats the tank (and it's a big one) in about twenty mins then the stat switches the boiler off. If you need the water heat topping up (not very likely) then another 30mins before you need to use it will be enough.
The idea of the boiler "topping up" the temperature 24/7 is madness and will cost you a fortune. In effect you are heating the water, letting it cool down then heating it again.

If you are going fully pumped you may as well go the whole hog and replace the boiler with a modern condensing boiler, I would guess with the age of your boiler you will save 25% on your heating bill especially if you fit TRVs throughout and modern controller/timer. Don't bother with a Nest or Hive or other gimmicky controls, it's far better to use the logic of "if I'm hot turn it off if I'm cold turn it on" and remember to turn if off when you go out. Unless you feel the need to call up your heating system with your phone in case it's lonely!