multibloc inlet valve connected up wrong

[pmx_super]

I overheard the engineer who serviced my unvented cylinder the other day checking something about the installation with his boss. He concluded with "it's not how we do it but I guess it's OK", and moved onto other more important matters (my non compliant flue).

I was curious enough that I looked at the Kingspan installation manual to see what I could find. It turns out that the connections to the Caleffi inlet control multibloc valve are wrong ( / unconventional / unsafe / illegal?).

The balanced cold is feeding the cylinder, with the "main" outlet (the one opposite the inlet) feeding the rest of the house with cold water, with a T off to the expansion vessel.

According to the installation guide the main outlet should feed the cylinder, with a T off to the expansion vessel. The balanced cold should feed the rest of the house with cold water.

How worried should I be?

 

[yorksbuilder]

The outlet should feed the cylinder
The expansion vessel should be connected to the part on the back side opposite the PG connection, not necessarily off a T from another pipe
The balanced cold (take off) should come out the bottom and go to supply the rest of the house.
The key point is that there is a check valve on the main outlet part to stop any expanded hot water feeding back in to the mains. Not sure if this means its happening in your case, and also not sure if there is ANOTHER check valve at the mains entrance to the valve.

Unvented hot water systems must comply with “The Building Regulations 2010 - Sanitation, hot water safety and water efficiency” section G3.

Get the G3 certified engineer back to sort it for peace of mind

 

[Johntheo5]

I think those two schematics are from a Kingspan link.

Some combinations valves incorporate a (the) NRV between the pressure reducing valve and the expansion relief valve and the EV is conndected to that blanked port directly below the expansion relief valve which probably what the lower schematic means. Yes, they are, it says it in the notes attached.

Can you post a few photos of your set up showing where its wrong?.

 

[pmx_super]

Blue is incoming cold main and the cold water to the rest of the house. Red goes to the unvented cylinder.

 

[Johntheo5]

From a safety point of view, even though the T&PRV is the main "safety valve" the expansion relief valve will lift first but there shouldn't be a NRV between it and the cylinder inlet even though the NRV will open to allow it to lift.

You say "The balanced cold is feeding the cylinder, with the "main" outlet (the one opposite the inlet) feeding the rest of the house with cold water, with a T off to the expansion vessel." so, the EV will absorb any expansion, but it can't return that expanded water to the cylinder because of the NRV when a hot tap is opened and will not release that water and pressure until some other cold tap is opened, not correct in any way.

As suggested "Get the G3 certified engineer back to sort it for peace of mind"

 

[pmx_super]

As suggested "Get the G3 certified engineer back to sort it for peace of mind"

Thanks for your analysis. I'll get a G3 engineer in, but the useless bloke who did the installation is long gone along with the useless builders he worked for and the crooked BC inspectors who signed it all off.

More surprising than the idiot who installed it getting it wrong, is the two guys who have serviced it since not saying anything to me.