Johnward & VicVapour

[EFLImpudence]

Simples.

Pipe stat to limit CH?
Or tell the kids it's hot. How did we survive?

In the MIs - 24V is not low voltage and 230V is not high voltage.



I thought the original post was being sarcastic but did you actually want to hire the services of someone.

 

[ecowarrior]

Simples.

Pipe stat to limit CH?
Or tell the kids it's hot. How did we survive?

In the MIs - 24V is not low voltage and 230V is not high voltage.



I thought the original post was being sarcastic but did you actually want to hire the services of someone.

yes ELV and LV - A common misconception that we have to live with.

The original post was not meant to be sarcastic at all. I am able to resolve all my electrics so no I am not after hiring someone - more trying to explain why I / We generally dont hire anyone.

As to the pipe stat limiting the CH - there has to be a fail safe on it for kids areas- and how does a pipe stat change the flow temp of the boiler? we are a bit further down the road than blending on flow temp with cold water to get other temps - we put a man on the moon 40 years ago? .

 

[mehran]

I think EFLImpudence posting that picture sums up the problem quite nicely...

you can't wire up a modern boiler with-out permanent live and the pump is directly wired to the boiler nowadays for pump over run... if you were the sparky on site and followed that wiring diagram I would need to give you a slap

add to the fact that this does not change the flow temp of the boiler.

At-least you were game for posting something

 

[ecowarrior]

Heating is nothing more than a series of switches. There's noting complicated about it at all.

I dont think NTC's Opentherm & ebus are simple switches? in fact not switches at all. A 40 year old S plan is just switches - but things have moved on - honest.

 

[EFLImpudence]

.
Perhaps I'm missing something.
As I said this is not my area but -

As to the pipe stat limiting the CH - there has to be a fail safe on it for kids areas-

You didn't say only the children's area.
I don't see how there can be, anything can fail.
Two pipe stats in series? Radiator cover(s)?

and how does a pipe stat change the flow temp of the boiler?

It doesn't have to if it turns off the CH when it reaches 80°.

we are a bit further down the road than blending on flow temp with cold water to get other temps - we put a man on the moon 40 years ago? .

Did we?

 

[ecowarrior]

.
Perhaps I'm missing something.
As I said this is not my area but -

My point exactly. I am sure you are brilliant at what you do - but would struggle with heating electrics

As to the pipe stat limiting the CH - there has to be a fail safe on it for kids areas-

You didn't say only the children's area.
I don't see how there can be, anything can fail.
Two pipe stats in series? Radiator cover(s)?

Sorry I just confused things there. Forget the kids play area my original brief was to keep the boiler condensating when servicing the rads. To do this the flow temp must be reduced as low as possible. (as to the fail bit - our stuff fails safe - as in if it fails it needs to be manually reset (like an RCD))

and how does a pipe stat change the flow temp of the boiler?

It doesn't have to if it turns off the CH when it reaches 80°.

he whole essance of my original question is that the DHW cyl needs 80 to comply to its recovery time - but a split second later - the Rads might call for heat and want to run at 65 degrees? All of this is done with (usually 240 in this scenario) external controls

we are a bit further down the road than blending on flow temp with cold water to get other temps - we put a man on the moon 40 years ago? .

Did we?

Well suposedly we did

I an not trying to set u up for a fall here & impressed you are hanging on in there. The day of the sparky running supreme I think is coming to an end. Your 240 volts (domestic) hasn't & wont change. A ring is a ring as a radial is a radial. Disconnection times will be worsted out the same with ohms law for eternity.

You are not bothered with efficiency. The bits u plug in to the installation may be more efficient with lower standby currents etc but the installation is just wire & outlets. On our side of the fence we have to design & supply the efficiency using all sorts of carlosfandango methods depending on the client his budget the Building regs and the heat loss of his particular dwelling.
This job is now more complex and technical than a domestic sparkies ever will be. Thats not me blowing my / our trumpets but I think you would have to agree. Having said that we have our fair share of brain dead installers! (plasterers with their brains removed I believe I herd mentioned!)

 

[Dan Robinson]

don't see how there can be, anything can fail.

It doesn't have to if it turns off the CH when it reaches 80°.

Where are Vic and John when you need them?

 

[ericmark]

423.1 A part intended to be touched but not hand-held Metallic 70°C so that's the maximum temperature of a radiator unless the likes of a Myson is used.

The problem is getting the domestic water hot enough with a normal hot coil heat exchanger. The Willis system may work but I am no plumber.

The boiler does not simply switch on and off any more but has two sensors the input sensor is the problem. This sensor ensures the return water is cool enough for condensing to take place and it first turns down flame height and then turns the boiler off as the return water heats up.

The whole idea is that the thermostatic radiator valves with the correctly set lock shield valves will ensure there is the correct temperature drop across each radiator and once hot it will switch off. Once they are all off the bypass valve opens and hot water is returned to the boiler which then turns the boiler off.

That's great but it will not work that way with the domestic hot water if one reduces the flow enough to ensure the correct temperature drop across the hot coil it will not be hot enough to heat up the domestic water and if you open up the flow then it will shut down the boiler.

So most boilers today are combi type where the heat exchanger is built into the boiler.

There are better heat exchangers on the market like the Megaflow which are in the main designed to combine multi-systems together but as far as I know this then involves far more valves to ensure the correct temperature at the radiators and taps and a much higher temperature used to transfer the heat from recirculating water to domestic.

The standard system used for years does not work any more because we need to ensure the return water is cool enough. Works with standard radiators but Myson radiators and domestic hot water have problems because of the return temperature of the water.

I am told by using a towel rail in series with the hot coil some compromise is possible the towel rail cools the water further after it leaves the hot coil so stopping hot water returning to boiler.

However this is not really an electrical problem it's all to do with the plumbing.

The electric side has become far easier with it all being built into the boiler don't even need a thermostat today as the anti-cycle software in the boiler takes care of this. The thermostat is only really to stop boiler firing up on a hot day it does not control room temperature.

This however presents a problem in arranging valves to divert water as all the old systems used the thermostat to control the motorised valve and that in turn worked the boiler.

So the only motorised valve is now the one controlling water to the domestic hot water supply this however means problems in the summer with the house being warmed up in morning by the central heating even when likely we will get a warm day latter.

So one still needs the motorised valve for central heating purely to be able to turn it off in the summer.

But really as I said not an electrical problem all down to plumbing. In real terms it's either a combi boiler or something like a Megaflow can't use a modern boiler with an old style system. It simply will not work.

 

[EFLImpudence]

(as to the fail bit - our stuff fails safe - as in if it fails it needs to be manually reset (like an RCD))

That a sore point with some here they fail to work sometimes.

On our side of the fence we have to design & supply the efficiency using all sorts of carlosfandango methods depending on the client his budget the Building regs and the heat loss of his particular dwelling.
This job is now more complex and technical than a domestic sparkies ever will be.

That may be so but I still don't quite grasp your original point.

I don't know how a lot of modern equipment actually works - that's not my job - but given the requirements I could design and install the circuitry.

Once you have designed the central heating system, if that is your job, then an 'electrician' would be able to design and install the circuitry for it.

Because your job entails electrics you seem to be complaining that my job doesn't involve plumbing and heating engineering.

Anyway, I'll quit while I'm behind. tfb.

 

[Dan Robinson]

@ericmark

Close, but still misunderstanding a few things.

Remember there is no "problem". Only a "method"; and it has nothing to do with plumbing.

AFAWK for the purpose of this thread, that has already been done - But Eco can correct me if I am wrong.

 

[ban-all-sheds]

Unfortunately your post makes no sense what so ever.

That is true of much of what he writes.

Perhaps he would have more success in communicating if he used English.

 

[oph]

Unfortunately your post makes no sense what so ever.

That is true of much of what he writes.

Perhaps he would have more success in communicating if he used English.

Makes sense to me, but then I understand what it is he's asking for, which is the very point of his post

 

[bernardgreen]

There are never any instructions with the boiler apart from hanging it on the wall. - its down to the Plumber to sort out all of the design & circuit diagram .

Two circuit diagrams are needed, one for the water flow and one for the electrics......

As ecowarrior has pointed out the requirement for hot water to be hot enough to ensure Legionella bacteria cannot survive in the tank and the conflicting requirement that radiators are not at a temperature that is un-safe to touch create problems for the plumber to solve.

Solving these complicates the electrics of the control system and the need for co-operation and understanding between electricians and plumbers is increasing. But sadly it seems the two trades are generally not working together, each blaming the other when things go wrong ( or never worked to begin with )

 

[bernardgreen]

So the only motorised valve is now the one controlling water to the domestic hot water supply~~~~~
~~~~one still needs the motorised valve for central heating purely to be able to turn it off in the summer.

And with the one valve for the central heating control all rooms are heated even if many of them are not being used. Altering the settings of radiator valves to not heat un-used rooms can create later problems with the balancing of the system leaving some rooms over heated and others under heated.

To get the efficiency of not heating unused rooms the control system has to become far more complicated with individual temperature sensing for each room and flow control for each radiator or room.

This introduces a third trade into domestic heating systems, the electronics engineer who can both set up and then fault find on electronic thermometers, flow controllers and networked control systems.

 

[ecowarrior]

But really as I said not an electrical problem all down to plumbing. In real terms it's either a combi boiler or something like a Megaflow can't use a modern boiler with an old style system. It simply will not work.

You speak much sense but the very issue is that there are re 10 million old systems all having new condensing boilers attached to them. ( about 5000 per day apparently)
There were no trick questions in this thread - just trying to stretch the mind & get u lads to think a bit ahead of old systems. I will post a diagram eventually but as BGreen has sussed - the two circuits need controls to give max flow temp for one (DHW) and lower temps for the other (C/H)
At least now we all understand the question. Question is - if you were tasked to do it - how would u design the circuitry?

RF Ligntning - your comments simply highlight the gap between our trades. I need two pre-set & determined flow temps from one boiler please?

ELF Impedance - I wasn't trying to get anyone to quit - just to explain where the problems arise between us. It will get worse as systems become more complex.

I see the chuckle brothers have stopped the insults to the point they have not even entered this discussion. I think that says it all. Perhaps their days of slagging us off for not ramp testing room stats is over?

I suspect this post will die out soon but it may of helped to explain some of the issues.