Is this article a Red Haddock ???

[JohnW2]

Over the years, the most troublesome part of our heating system, has been the 3-port valve actuator. A basically simple device, but under tremendous strain, from a spring, wound up by a constantly powered, stalled clock type motor, to retain the valve open. Such a daft idea, I had it in mind to design something better, and more reliable, to operate the valve.

Indeed. It's always seemed totally daft to me - to the extent that I initially told people that they surely couldn't be right in saying that that is how they work. To have a motor which spends the vast majority of its life 'stalled' seems just plain crazy - and, as you say, it surely would be possible to design something more sensible?

 

[ericmark]

Seem to remember there was a sequence of events which could leave it activated even with heating off?

 

[ebee]

"a spring, wound up by a constantly powered, stalled clock type motor, to retain the valve open. Such a daft idea,"

I must admit that when I first came across it I thought the same and in the heating fraternity it is thought of as normal.
It mightjust be that it keeps the cost down and therefore not too relevant.
Someone might know the answer, I do not.

 

[Harry Bloomfield]

I must admit that when I first came across it I thought the same and in the heating fraternity it is thought of as normal.
It mightjust be that it keeps the cost down and therefore not too relevant.

I, numerous times, cursed the whole idea.

 

[JohnW2]

I must admit that when I first came across it I thought the same and in the heating fraternity it is thought of as normal.

Indeed - as I recently wrote:

Indeed. It's always seemed totally daft to me - to the extent that I initially told people that they surely couldn't be right in saying that that is how they work. To have a motor which spends the vast majority of its life 'stalled' seems just plain crazy ...

It mightjust be that it keeps the cost down and therefore not too relevant.

Maybe, at least the initial cost. However, I'm not so sure about the long-term 'cost over time', since I can't help but think that a motor which spends so much of its life 'powered but stalled' is probably going to need to replaced appreciably more often/frequently than one which is used more sensibly?

Someone might know the answer, I do not.

Same here!

 

[Harry Bloomfield]

which spends so much of its life 'powered but stalled'

They are simply stalled, by the insertion of a diode, once the desired position is obtained.

 

[JohnW2]

They are simply stalled, by the insertion of a diode, once the desired position is obtained.

Can you perhaps help me to understand that statement?

 

[Harry Bloomfield]

Can you perhaps help me to understand that statement?

When the actuator, is in the correct position, to trigger the microswitches, a diode appears in series with the motors supply.

 

[JohnW2]

When the actuator, is in the correct position, to trigger the microswitches, a diode appears in series with the motors supply.

That's really just a repeat of what you wrote before(which is something I hadn't previously heard of).

What is the diode meant to achieve, and in what sense is the motor 'stalled' when the diode is in-circuit?

 

[morqthana]

There is a reason to turn heating completely off, when one leaves the house for example, and geo-fencing will do that for you. But it is the turning back on which is the problem. Living room radiators are around 2 kW each so 4 kW in all, it does not matter how big the boiler is, or how fast it can heat the water, from 16°C to 20°C will take around an hour, so it needs to start the heating even in a built-up area in Wales at least 20 miles from home, in England 30 miles from home, and in the country 40 miles from home. But that would only work if going over 20 miles from home to start with. My geo-fencing waited for me to be about to step through the door before turning back on, basic when your phone connects to local cell.

Plan B:

If you return earlier than your predicted time, just put up with the house being a little bit chillier than you would like - put a jumper on, man up, and live with it for half an hour, you won't die.

 

[morqthana]

The main reason for wanting high power output on a combi is to allow running a bath in a reasonable length of time.

Do any of them?

 

[morqthana]

With 'all dumb' TRV's the Time clock calls for heat which the boiler provides and when all TRVs are satisfied a sensor on the return pipe stops the boiler, this is far too often incorrectly left to the boiler sensors (not so much these days). IE; the boiler overheat stat operates. – A poor system as the boiler may be constantly going through a heating and long cooling cycle and not be available when a TRV opens. Adding a room stat is complex as the room monitored could be the first to reach TRV set point so one has to work out what temp to set the stat to – yada yada yada.

With a 'zoned' system where each zone has a space stat and motorised valve, (Imagine a block of flats with a communal heating system).

With a 'full intelligent TRV' system one is effectively creating a series of zones and each can call for the boiler to provide heat and can be used in isolation.

So I'm in a room which has been designated to be at Xº because it's Y-o-clock. And for some reason, I don't want it at Xº, because I'm there when I'm not expected to be at Y-o-clock, or I've got a cold and am feeling pathetic and sorry for myself and I want it warmer. Whatever my reasons, in which of the systems you describe above is it easier and therefore better for me to adjust TRVs rather than a control on the wall?

 

[plugwash]

Do any of them?

Depends, on what you mean by "reasonable" I guess, the 35KW ATAG I have at my current place is ok as a single occupant, but still noticably slower than the traditional tank-based setup at my parents house. I don't think I'd want it as a family. It seems noticablly better than the 28kW bosch I had at my previous place.

 

[ericmark]

man up, and live with it for half an hour, you won't die.

The problem is my hand has been de-gloved in an industrial accident. This means I have a problem if either too hot or too cold, just something I have to live with.

 

[ebee]

Maybe, at least the initial cost

Yes John that is exactly what I meant, not the running costs - again with plumbing/heating on long runs from boiler etc to have a pump permanently running a head of water on constant circulation to avoid the end users of long runs wainting "a long time" to receive it after turning tap on, obviously a few might actually benefit if the run is exceptional and usage average extremely high but for a great many I would not think that much better if any - and in the cases I was aware of a pump more expensive and long lasting, probably a trade off situation that could, in a few instances, actually make it cheaper but the majority, I suspect is more for convenience, obviously if you are running a hotel it might make better business sense to have every aspect equal or a little better than rivals to keep revenue top end in comparison to rivals so that does come into the mix too I would think.
I have not seen the actual sums so it`s just my guess.

Talking of business sense, we constatly see all sorts of ploys in supermarkets attempting to compete by shaving a penny off here and there compared to rivals and I`m sure many of the managers are more on the accounting side and fail to see common sense sometimes
.
Example - One competing supermarket around our way decided to stop the practice of allowing custermers to choose a pizza with their own choice of combination of toppings etc. Save a bit on wages and maybe on some stock.

I was instantly appalled at the idea, I imagined with a great choice of rivals around our way it might deter a high number of people from getting any pizza at all and surely some of them would be inclined to change their whole shopping ethos and change to an alternative rival and some might stay changed.
I might have been correct I can`t say for certain but after not many weeks the situation reverted back, I have no idea how many custemers changed shops temporarily or permanently , if at all.

However if I was correct (I can not confirm that) then how come the decision makers could not see what to me (a humble electrician) can see.
I am also aware of some ideas including not just retail but manufacturing etc as well that not only cheeses off customers and/or encourages shoplifters but cheeses off staff as well to save a few shillings, to risk losing happy customers and cheese off staff to save a little can have real, bad outcomes, happy staff tend to work more in the firms interest and customers ditto.