Several things wrong with new flat - no central heating, low hot water pressure even with water pump, noisey pump

[John Rumm]

You may have to take the cap off the heater to see that - it is often a small screw control with a temperature scale round it.

[John Rumm]

Chances are it is a spring return diversion valve then. Don't worry too much about it until you have proved the room stat signals are being generated and getting through correctly though.

[John Rumm]

If you want to get into it...

(although see other comments regarding the room stat first)

Looks like:

ok - so lets say i take off the cover from the box on top of the brass

Possibly, but not always.

You may only have the choice of CH or HW on the valve. If that is the case when he programmer asks for CH & HW the valve will just do HW.

You will probably need to take the motor off the shaft coming out of valve body first...

Not necessarily. If the valve is a mid position type (rather than a simple spring return one) then you need to prove that the request that puts the valve into the CH position is actually getting there. Since without that you would get the symptoms you are seeing and the valve itself may actually be fine.

No, I mean the time switch. ("programmer" may be a bit over egging the description for some of the older boiler time switches!)

Many of the immersion time switches carry the full load current of the immersion heater. Hence you would expect to usually have a pair of hefty T&E cables coming in and out of the controller.

Yes.

Tis because the valve is in the HW only position.

Either because it is knackered, or something that ought to be telling it to do something other than HW is knackered!

Good luck!

[Dave Plowman (News)]

I'm now assuming you're a troll.

[Dave Plowman (News)]

You really are rattled? Nice.

Of course answering the problem is again too much for you. You'd get a man in.

[OldBill]

I think so too, the whole thread is complete windup or the guy is a fool who shouldn't be messing with this.

[OldBill]

Why does this guy keep mixing up the immersion circuit with the electrics for the CH system? They are not related at all. If he is not a troll he is in danger of doing himself harm.

[Doctor Evil]

Well it takes one to know one.

[Doctor Evil]

Please do take any notice of this man when it comes to heating.

[riccip]

And therein lies the problem. Using your boiler just to heat HW alone is a bit like putting a V8 engine into a moped. That's why combi-boilers were invented (although personally I hate the wretched things!).

An immersion heater is 100% efficient from the moment it switches on and requires minimal energy to maintain optimum water temperature. A gas boiler can be as low as 50% efficient when heating just the copper cylinder. The system has a warm up period where no heat is being transferred. Much of the heat produced by burning gas disappears up the flue and more is lost from the pipework runs to the HW cylinder, often positioned some distance from the boiler.

It's not that simple an equation. A boiler works hardest when warming the house from cold. Once the desired temperature has been reached an efficient CH system with TRVs burns considerably less gas maintaining those temperatures. So the sooner desired room temperatures are reached the better and more economical. Therefore if the HW cylinder has already been heated on Economy 7 the boiler will more rapidly heat the house.

Ask amongst your friends and you will be surprised at the number of people who leave the boiler on all day to keep the water hot. Even if it's timed for an hour it will begin to cycle according to the boiler's stat, thus wasting an incredible amount of gas. As HW is used, even a minimal amount, the boiler works hard to reheat that portion of the cylinder.

Certainly on peak-time electricity it would. However peak electricity shouldn't necessarily be considered taboo. Take an electric shower for example. Heavy on electricity but only for a few minutes, offering considerable savings over a gas heated shower arrangement.

riccip

[Doctor Evil]

Total tripe. Gas is approx 1/4 of the cost of electricty. You heat DHW with gas AT ALL TIMES. A larger bopioer means a quick recovery rate.

Combi boilers were invented by the French in the early 1960s and they were invented to save space. Good combi's work very well, cheapo's not so well - same will many things in life.

Not if you have a quick recovery coil and two cylidner stats, it will not.

You talk total and utter balls!!! Stop making things up.

[riccip]

Uninformed.

Illiterate.

Hardly a clever troll but you have amusement value.

riccip

[bigcat]

what exactly is the problem? I'm not seeing one.

yes, but thats not the whole picture. but its downsides normally outweigh the upside.

please tell us which new gas boiler is 50% efficient. And when and why one would heat just a copper cylinder.

yup, same for immersions. Measured in seconds in both cases.

well, 5 - 10%

very little.

ok

not quite that simple

it makes no difference whether the HW is heated before or after the morning house heat up. Only when its heated during, which some systems do permit, will it make any difference to heat up speed. But its really no big issue.

why is it incredible?

you mean the same as an immersion does?

Just how is 100% efficient 7p/unit electric heating cheaper than 90% efficient 2p/unit heating?

NT

[Mike]

Although I think gas does still win out, all the energy from the electric immersion heater goes into the water whereas running up a boiler 'from cold' means it has to heat itself, it's piping and so on as well as the water. But I still think gas works out better simply because it is so much cheaper.

No - electric is seconds - gas is minutes.

[bigcat]

its 10-20 seconds here.

NT

[Dave Plowman (News)]

That might be so locally, as in your house, but you have to consider how that electricity is generated.

But the initial heating up of the boiler and pipework doesn't take long with a modern boiler and once this has happened it should run at its normal efficiency while heating the cylinder which with a fast recovery type will be accomplished in a fraction of the time needed by an immersion.

[Doctor Evil]

Unless it is a 20kW immersion heater, gas is faster.

[Doctor Evil]

You clearly have not a clue, and make thing up. If you want to know just ask.

[Mike]

I think you've missed the original quote. We were talking about the initial warm up time when no useful work is done.

[Doctor Evil]

Which is so short it is irrelevant to the main point.