Ideal Logic+

[adlplumbing]

agile plastic pipe would accomdate it but as mentioned most water meters come with double check vavle when installed quick way using wab vavle
since most these are on exsiting propertys you think it should be taken into account

 

[vulcancontinental]

Unsure what a WAB valve is.

My understanding is that when the first Vaillants came out they fitted them with the mini ev because on the continent it's mostly permissible to allow expansion from combis and unvented hot water cylinders back into the public main. They forsaw the problem which was switching the boilers on when a cold tap was turned of which resulted in a sort of 'wave' back down to the flow switch that could start the boiler up. It's not particularly the expansion of the water. Fast closing washing machine valves can also give a problem. Later boiler models found other ways to start and stop the boiler that were not affected by on water 'movement' in the cold main/hot outlet that were less prone to this nuisance.

In the UK it is theoretically not permissible to allow water back into the public main hence the double check valve - any plumbing arrangement that can lead to contamination of the public supply should be fitted with one or have an air gap like a ballvalve.

I was taught, correctly or not, that once the water is in your property it is treated as contaminated by the water authority.

Mixer outlets that mix in the valve body rather than at the spout are a case in point if the cold is mains water fed.

Don't even start thinking about upward spray bidets on a combi even with usable pressures as the spray nozzle will often be immersed in faecal matter.

If I've stated the bleedin obvious my apologies.

Breaking the double check valve on a water meter is very naughty or would be if the water boards had teeth and inspectors and I think is a £200 a day fine till it's put right. Why would you break one anyway? To stop the boiler firing when a cold tap is closed suddenly?

 

[shambolic]

Its actually in the fitting instructions if a water meter fitted or double check valve or non return on cold main then a mini expansion vessel must be fitted.

I have actually seen the washers being pushed out the plate due to rapid exp with nowhere for it to go, over 12 bar on the reducing valve gauge(the pressure reducing valve locked up acting like a non return valve).

FROM A MEMO

Details:
Some DHW installations have long and used pipe circuits creating air locks or
similar conditions where operation of a cold tap could create’ hammer shocks’
that pulse back through the boiler DHW circuit.
If these runs can be identified they should be altered to overcome the problem
of creating a ‘false’ DHW demand. The customer would see this as the boiler
operating erratically for a short period wither with or without the boiler firing. If
the DHW greater than 2 l/m disappears after 0.5 seconds but before the burner
lights the PCB will run the pump for 1 minute and the fan for 4 minutes

 

[shambolic]

Just a wee note it has 5 year warranty so get Ideal out

 

[shambolic]

It is normal practice to utilise the rising main for expansion of water from DHW
heating appliances but with such a device fitted this cannot happen – the
expansion is limited.
In the installation and Service manual, Ideal Heating caution the requirement to
accommodate the expansion of water for installations with such devices fitted.
NB This caution is also displayed in the instructions for external devices and
leading competitors’ instructions.
Extract from Logic Combi literature –
IMPORTANT
Provision MUST be made to accommodate the expansion of
DHW contained within the appliance, if a non-return valve is
fitted to the DHW inlet, or a water meter with a non-return valve
is installed.
NB – This failure mode it NOT a boiler fault and should be rectified by the
installer prior to the boiler being operated further to prevent re-occurrence
Ideal Heating provide a DHW expansion vessel option kit for our combi ranges,
part number for this is 175600
Boilers

 

[adlplumbing]

vulcanancontinental
wab vavle contains drain off and double check vavle and attachment for manifold meter which is screwing type which also use in the ground

i know about breaking the double check as it may need to be done in some circumstances due old pipe work as it can cause water hammer
and few other problems due too poor water pressure

but as mentioned if this causing problem to a new boiler that boiler manufactures are responsible as they know the water regs
and if dead legs causing problem they should designed for this for boiler swap conditionss
yer it on 5 year warranty so get them out

 

[Happyplumber]

The IDEAL BLAME GAME begins!!!!

Far from IDEAL!

 

[Agile]

This thread started in relation to spurious boiler response to a dead leg.

It has now been moved on to expansion of water in the boiler/hot water taps.

This "problem" is not specific to Ideal logic boilers but any manufacturer's boilers.

Its not a problem that I have ever been called to although I appreciate that a staff engineer might see it.

However based on what I said above can any explain how this expansion comes about?

Tony

 

[adlplumbing]

agile
but how come a modern combi boiler can not cope with it since it going to get worse as more double check vavles are fitted with water meters

 

[Agile]

As I said I have not experienced any damage to a combi boiler from that.

Nor do I see why it should happen as heat is only applied during DHW usage.

Tony

 

[transam]

Can't say that I have ever come across it , neither do I know any one who has , maybe it becomes more relevant on those combis that have a preheat mode or option ???

 

[Agile]

Dont forget that Vaillant stopped fitting the mini EXV to their Sine 18s during the production run.

That one also has a preheat function.

Of course widespread metering is only a feature of the last 10 years.

But only more recent meters have had that NRV.

Tony

 

[vulcancontinental]

Dont forget that Vaillant stopped fitting the mini EXV to their Sine 18s during the production run.

That one also has a preheat function.

Of course widespread metering is only a feature of the last 10 years.

But only more recent meters have had that NRV.

Tony

Yes, and when the problem first occurred and I rang into tech help they said empty the mini exp vessel, as it can actually be a contributing factor sometiimes.

I think it can also be a result or combination of certain factors - CW service pressure, internal property plumbing layout (like water hammer etc) and there is more than one method of signalling water flow, some may be less prone to the problem than others.

 

[PEDANTICVINDICTIVEMAN]

And so the best way forward to stop it is.................

 

[adlplumbing]

tell ideal to get their arse out or mini expasion vessel i guess

and agile nrv on a meter may be recent thing but not as recent as this boiler so i still say its a design flaw if it can`t cope with it