Unvented cylinder wrongly fitted

[tcas]

I have an unvented mains pressure hot water cyling (Megaflow) which has been fitted without the two port cut-off valve that I belive is supplied with it.

I'm told that I need to have the two port valve fitted in addition to the existing 3-port valve as the 3-port valve does not provide isolation in the event of failure of the thermostat on the Megaflo.

Is there any way of making the system safe without having to drain it down and fit the two port valve.

Thanks
Tim

 

[corgiman]

nope that two port valve MUST be fitted.

this is because a three port valve if it fails stays open to hot water, but if a two port valve fails its spring closes it totally.

The G3 registered engineers who fitted it should have know and should have fitted it so get em back

 

[htgeng]

I have an unvented mains pressure hot water cyling (Megaflow) which has been fitted without the two port cut-off valve that I belive is supplied with it.

Is there any way of making the system safe without having to drain it down and fit the two port valve.

Thanks
Tim

Did the installer complete the megaflow benchmark booklet? You really need to answer that question first before anyone goes into the technical side of the install.

 

[tcas]

It was fitted when I had a loft conversion five years ago, which I suspect may be befor G3 came out and I don't remember any mention of the megaflow benchmark booklet.

 

[tcas]

If the two port valve is intended to cut off water to the cylinder when it gets hot or the thermostat fails, can't I just have the system wired so that the boiler and pump are turned off in the event of thermostat temp exceeded or thermosts fails.

I can't quite see what additional protection this valve provides. Or am I missing the point.

 

[Agile]

Thats an interesting question!

In your case NO because the manufacturer does not permit it!

The whole point is that the gas valve in your boiler may stick on and you will have no protection whereas the 2-Port will give that protection.

However, the Vaillant unvented cylinder does just that with the paired Vaillant boiler.

Tony

 

[Paul Barker]

I don't know what g3 stands for but I have my unvented cert. and would have used that valve.

But I just wanted to pipe up because you said maybe fitted before g3 (whatever that is).

Fact is it has always been a requirement to hold a qualification to do that job in the UK.

They might have held the qualification but had a momentory lapse of conscentration or they may be cowboys.

Worth asking LA whether they registered the job with them because it should have been registered before commencement of work. Let LA chase them up and maybe if they aren't qualified you commission a suitably qualified person to re do the work properly register it properly and send them the bill via solicitors letter cost of which included in bill.

 

[tcas]

OK. So what is the registration process?

Does someone from the local authority come and check the installation?

I've got someone coming to install the 2-port valve, I guess I could really do him certifying that the system is correctly installed and then submitting that to the local authority. Does that sound right?

 

[Paul Barker]

Before corgi made it part of their remit I used to go to planning department and state what I was planning to install, they took the details from me and a copy of my qualification.

Now I simply inform corgi who inform the counciul and send you a certificate of compliance.

That's how I do it anyway.

You may end up with a vist and a £100 fee in which case seek recompense from installer for whome if he were qualified at the time it would have been a simple process as in para one above. There would have been nothing to pay but the law would have been complied with. Yes, it is law and always has been to inform LA of any unvented installation before commencement of work.

 

[tcas]

OK. Thanks for your help.