Expansion vessel service valve

RJF

Looking for thoughts, opinions and regs regarding the fitting of a service valve on an expansion vessel for a heating system.

Wearb

Don't think they are allowed.

You can't fit one on domestic expansion vessel, but you may get away with one on a secondary expansion vessel.

RJF

Hi Gary, thanks for reply.

Do you mean its illegal to have one or against regs or just poor practice.
I'm not talking about PV in a system boiler but an external vessel.
In particular I was thinking about a situation where an PV is connected to a pipe with a flexible hose which has an integral shut off valve.

RJF

Actually just thinking further.... a system boiler has shut off valves on the flow and return (god!!!! - how they like to leak) so this effectively is equivalent to a service valve on the PV????

Dtp1979

RJF wrote: »

Actually just thinking further.... a system boiler has shut off valves on the flow and return (god!!!! - how they like to leak) so this effectively is equivalent to a service valve on the PV????

A system boiler has the vessel and prv on the correct side of the valves though

RJF

True Dtp.
I seem to recall some MI for an undersink water heater requiring a service valve on the expansion vessel. Not sure???

RJF

Just found this.

RJF

RJF wrote: »

True Dtp.
I seem to recall some MI for an undersink water heater requiring a service valve on the expansion vessel. Not sure???

Heating and unvented cylinders have different regs, for a unvented cylinder/under sink water heaters you must fit a expansion vessel as close as is practical to the cylinders cold feed connection. no isolation valves, check valves etc are allowed between the vessel and the cylinder.

Expansion vessels fitted within most gas boilers are classed as the primary expansion vessel and as DTP posted they are the correct side of the boiler isolation valve, as the secondary expansion vessel already has a isolation valve between the vessel and the boiler I don't think there would be much drama from fitting a lever valve and removing the handle.

solar expansion vessels have inbuilt isolation valves to save draining the glycol

gifted

It's the norm to fit a Lock shield valve in an industrial setting

gifted

gifted wrote: »

It's the norm to fit a Lock shield valve in an industrial setting

I think its to do with volume and practicality, draining a domestic installation is easy, even I can do it (from what I remember).

RJF

Thanks for all the replies.
So Gary, what is the reg that says you can't put an isolation valve on the vessel and where can I find it.
Also does it say that you can put one on a secondary vessel?

The reason I asked the question in the first place was because I read the following on PHAM News, a technical magazine. (PHAM stands for Plumbing, Heating and Air Movement.)

Just wondering what people here on boards thought.

"Another one that bugs me – although I am not sure it is a regulation, more something I was trained never to do and most installers have the same belief – is not putting an isolation valve on an expansion vessel. Of course you should. Of the whole heating system, the expansion vessel is the biggest cause of breakdowns, the reason we are told is a safety issue, if the valve is closed then expansion cannot take place. Well fit a bloody lock-shield type for goodness sake, or as I and other installers do, fit a full bore lever valve and remove the handle.

You also need to fit a drain valve between the valve and expansion vessel. We could reduce heating system failures by a large proportion IF on service the vessel can be isolated, drained and the pre-charge pressure checked and adjusted if required. Installers don’t check this on service as it would usually mean draining the entire system to do so. An expansion vessel WILL need pre-charge adjusting during its life and it is quite likely the vessel will fail in the system’s lifetime.

We also need to educate installers to ALWAYS check the pre-charge pressure on annual service. This alone would reduce the amount of boiler breakdowns massively. As usual though we have to look to Europe, which already has this covered.

I found a fantastic product made by *****, who manufacture expansion vessels (German) and are distributed in the UK by ******. It is a combined lock-shield isolation valve with built-in drain valve, which has the connection to screw directly to the expansion vessel. In my opinion this item should be sold with ALL expansion vessels, as not providing isolation for service is very bad practice in my opinion. I will now fit this valve from ****** to all my expansion vessels."

Dtp1979

RJF wrote: »

Thanks for all the replies.
So Gary, what is the reg that says you can't put an isolation valve on the vessel and where can I find it.
Also does it say that you can put one on a secondary vessel?

The reason I asked the question in the first place was because I read the following on PHAM News, a technical magazine. (PHAM stands for Plumbing, Heating and Air Movement.)

Just wondering what people here on boards thought.

"Another one that bugs me – although I am not sure it is a regulation, more something I was trained never to do and most installers have the same belief – is not putting an isolation valve on an expansion vessel. Of course you should. Of the whole heating system, the expansion vessel is the biggest cause of breakdowns, the reason we are told is a safety issue, if the valve is closed then expansion cannot take place. Well fit a bloody lock-shield type for goodness sake, or as I and other installers do, fit a full bore lever valve and remove the handle.

You also need to fit a drain valve between the valve and expansion vessel. We could reduce heating system failures by a large proportion IF on service the vessel can be isolated, drained and the pre-charge pressure checked and adjusted if required. Installers don’t check this on service as it would usually mean draining the entire system to do so. An expansion vessel WILL need pre-charge adjusting during its life and it is quite likely the vessel will fail in the system’s lifetime.

We also need to educate installers to ALWAYS check the pre-charge pressure on annual service. This alone would reduce the amount of boiler breakdowns massively. As usual though we have to look to Europe, which already has this covered.

I found a fantastic product made by *****, who manufacture expansion vessels (German) and are distributed in the UK by ******. It is a combined lock-shield isolation valve with built-in drain valve, which has the connection to screw directly to the expansion vessel. In my opinion this item should be sold with ALL expansion vessels, as not providing isolation for service is very bad practice in my opinion. I will now fit this valve from ****** to all my expansion vessels."

Why is the name of the valve omitted?

Dtp1979

Dtp1979 wrote: »

Why is the name of the valve omitted?

I read that article it's not technical at all it's the rantings of a installer who is the end user and would have little experience of the things that go wrong. What he doesn't understand is the unvented design requirements are based on safety(not a controls manufacturing conspiracy :pac::pac:) and as yet are best as they are proven, no manufacture or regulation body will change a safety requirement until it's proven to the same standard as the original.

As he mentioned in the article fitting valves are against water regs.

RJF

Dtp1979 wrote: »

Why is the name of the valve omitted?

Just didn't want to seem to be promoting anything especially if against regs.
When I thing about it we mention products here all the time. Nothing sinister

Can anyone point me to the reg concerning service valve?

RJF

RJF wrote: »

Just didn't want to seem to be promoting anything especially if against regs.
When I thing about it we mention products here all the time. Nothing sinister

Can anyone point me to the reg concerning service valve?

For unvented it's G3 for CH systems there will be a similar British Standard and solar has its own regs.

RJF

Thanks Gary, but isn't G3 British? I'm looking for Irish reg.

RJF

RJF wrote: »

Thanks Gary, but isn't G3 British? I'm looking for Irish reg.

G3 regs are enforced in Ireland

RJF

Thanks Gary, but under what reg or statute or guidance are they enforced in Ireland?
Is it all of G3 or parts of it or what.

I'm just trying to clear up exactly what is the requirement here in Ireland.
Is it a law or regulation or best practice or grey area or what.

In other words where can I find information regarding the installation of expansion vessels here in Ireland. If there is none and we just follow British practice - fine, but is this the case.
Is there anything in Part J or L of Irish TGD or in another part?

RJF

RJF wrote: »

Thanks Gary, but under what reg or statute or guidance are they enforced in Ireland?
Is it all of G3 or parts of it or what.

I'm just trying to clear up exactly what is the requirement here in Ireland.
Is it a law or regulation or best practice or grey area or what.

In other words where can I find information regarding the installation of expansion vessels here in Ireland. If there is none and we just follow British practice - fine, but is this the case.
Is there anything in Part J or L of Irish TGD or in another part?

There is no enforcement until there's a claim , that's why expansion vessels, lack of safety valve pipework, auto filers are still around where as installers of undersink water heaters and unvented cylinders have their work to be deemed negligent due to not following G3 safety regs costing them personally €10,000s

RJF

So are you saying that there is no regulation or official guidance here in Ireland?

K.Flyer

Zilmet, who are one of the big brand names when it comes to expansion vessels, says this about siting an expansion vessel on a heating system.

Zilmet pdf download

Installation Siting
The Expansion Vessel must be fitted to the Return Side of the Central Heating System and in such a way that there can at no time be an obstruction between the vessel and the system.

However, at the same time, I do see the advantages of having a method to detach a vessel without having to drain down a system being very advantageous, as long as it was necessary to use tools to isolate the vessel and not a valve that could accidently close or be closed.

RJF

RJF wrote: »

So are you saying that there is no regulation or official guidance here in Ireland?

Commercially there's loads as there is domestically but domestically plumbers get no respect so domestic plumbing has been reinvented by those who no not what they do and I included building engineers, planners who are to arrogant to ask a qualified plumber for advice , often installers choose to ignore the good working practices taught to professional plumbers which would be based on Irish regs and by ignoring them they install unique installations that leave them liable in the event of a claim( other than insurance claims I have seen no other inforcement which is strang bearing in mind the brutal work that's out there.

Let's take unvented cylinders, they come with MI that have pictures, the MI is G3 regulations but as there are no real regulations for these pertintual bomb in Ireland some installers choose to ignore the installation requirements because they don't see the point(and I'm not linking that point to your query I'm just bitching)