boiler, trv and thermostat settings

unclebulgaria

Forgive me for being thick but isn't it obvious that if you turn off your heating its not going to use gas????
It says more economic (sic) not no gas bill at all. I wasn't saying that keeping your boiler switched on was cheaper than not having it on at all!
If I don't go out in my van I don't use any Diesel, if I go out in my van and drive sensibly I use less Diesel. Come on, isn't that common sense?
I'm quoting what I was taught, have read, have seen and tried.
I suppose its horses for courses isn't it.
A large house is going to take a lot more energy to heat than a smaller house with less volume to heat, that's a given.
Perhaps what I should have said was "shut your doors, set your TRV's to suit the rooms usage (regular use/occasional use), turn your boilers thermostat down a notch or two, set your room thermostat according to your requirements (whether you're in/whether you're out) and you will find your gas usage is at its minimum during operation. Failing that, turn your boiler off completely and put a jumper on!"
besksfaz, did you actually have all 14 radiators turned up to full on your TRV's and doors open or were they down to suit the rooms usuage and the door shut? Is your house insulated, double glazed?

unclebulgaria

Cardew wrote: »

Some points on your post.

As stated above, I agree that having the roomstat in, say, the lounge can cause problems i.e. lounge up to temperature on stat, so no heating in, say, bedrooms regardless of TRV setting.

However it is simply not always possible to have the roomstat fitted in a position in the house that has a ' mean/average temperature'. For many people the other locations for the stat is in the hall, and these days people simply don't want to heat their hall. In any case you have exactly the same problem with the stat in the hall i.e. hall up to temperature on stat, so no heating in lounge.

(answer)Nope you're wrong, every single house will have one room that is the mean temperature of all the others its just a case of finding out which one it is, and I agree that's not so simple in some houses but it exists.
No-one wants to heat an area they wont use but I think you'll find that a cold room/area will act like a heat sink to a warm room especially if the doors are open.

You seem to feel that if the pump is running, all the time CH is switched on, it is a big problem, but don't give a reason.

(answer)Sorry if i mislead you, nearly all boilers have a pump overrun facility but it only comes into play in long periods of shut down between firing or when the timer has moved to the off position. Pumps running all the time (when the boiler is off) means the system isn't correctly set up. (does that make sense?)

Also on the boilers thermostatic control again you make an analogy to a car driven flat out - which is not correct. On Non-condensing boilers there is virtually no difference in efficiency regardless of the water temperature.

(answer)Actually that's a good point, I suppose the only answer would be is how hot to you require your radiators to be, older rads/boilers are designed to lose 11 degrees across flow and return so even a low setting would eventually give the required warm rooms. I'll think of a better answer to that when I have more time. :rotfl:

On condensing boilers lower water temperatures, and hence lower return temperatures, will be of some help to greater efficiency. However it is not to stop them working 'flat out' like a car - which implies greater strain on the boiler.

(answer)I'm a bit confused about this response, new boilers should be run so that the boiler condenses more efficiently, 20 degree temperature differential across flow and return and a return temp of about 55 deg 'ish and they suit a more steady operation rather than full on full off. They modulate anyway so its easy to set these type of boilers.

Lastly can you explain your 'keep heating on all the time recommendation'. That is against all the advice to have the heating off as much as possible - for economy reasons.

For instance if the room with the stat is at 20C, and

1. You go out and turn the stat down as you suggest.

(answer)If you go out for a short period, say a few hours, drop the thermostat down from 19 deg to 12 deg, this then allows the house to keep some heat energy and shouldn't take too long to reheat as opposed to turning it completely off.
or

2. Turn off CH.

(answer)If you turn off your heating you wont use any gas, simple! But when you do turn it back on your boiler will be running for a longer period to get back to the required 19 deg.

When you turn back on the CH, or the stat back up, how does using the roomstat give a 'gentle temperature curve rather than huge temperature fluctuations that keep your boiler working overtime.' ? and not turning on the CH. i.e. what is the difference in operation?

(answer)Draw a graph with time at the bottom and temperature as the vertical line, now draw a line showing temperature at 19 deg and dropping to 12 deg and how long it takes to recover the lost 7 deg. Then do the same for 19 deg to 7 deg. You'll see what I mean.
If what I've said doesn't sound right, give your boiler manufacturer a call and speak to their tech line, maybe I'm not explaining it properly?;)

becksfaz

unclebulgaria wrote: »

besksfaz, did you actually have all 14 radiators turned up to full on your TRV's and doors open or were they down to suit the rooms usuage and the door shut? Is your house insulated, double glazed?

It's a rented house and we don't have TRVs on all the rads so this is one of our problems. I've messaged the landlord about putting them on all rads but no response at the minute (can't see him doing it though as it's of no benefit to him really). Out of 14 rads only 5 have TRVs! I do keep doors shut, house has loft and wall insulation and all double glazed.

unclebulgaria

becksfaz wrote: »

It's a rented house and we don't have TRVs on all the rads so this is one of our problems. I've messaged the landlord about putting them on all rads but no response at the minute (can't see him doing it though as it's of no benefit to him really). Out of 14 rads only 5 have TRVs! I do keep doors shut, house has loft and wall insulation and all double glazed.

How often I hear that. There's a misconception that when a new boiler is installed you must update the radiator controls too. I contacted my local building control and spoke to one of their guys to query this and was told it is not a regulation that states TRV's must be fitted once the boiler is changed, he actually said that so long as the change of boiler was increasing the efficiency of the heating system then I was complying with building regs. I have checked a number of times to clarify this and get the same answer.
If you dont mind me suggesting something to try that has worked before when I have worked on older systems.
If you go to the rads that have no TRV's on... these rad valves are called lockshield valves and can be plain or complete with a drain off as part of the body of the valve. If theres a shaft that isn't jammed open or shut you can actually close these valves down completely or partially. Slowing the flow of water down through the radiator will cut down the amount of water the boiler is having to heat, you might have to trial and error this so that you dont make the rad cold. Best way to start is pick one end of the rad (this only needs to be done on one end) wind down the valve shaft clockwise, then with the heating switched on wind the shaft anti-clockwise just one turn at a time until it starts to warm. It may make the rad slightly cooler than normal but may help to cut down your fuel bill even if only a little.