installation of Boiler - Unvented tank

As part of a rebuild (added 1st floor to bungalow and extended back) we have removed every piece of plumbing and electrics, during COVID

In preparation for the complicated stuff, during the build we have ...

• Gledhill unvented tank (preplumbed) placed in 1st floor airing cupboard
• New radiators and pipework in CH system piped back to 1st floor airing cupboard via up and adjacent to Gledhill tank but not connected at all
• Electrician has connected all heating/hot water controls attached to preplumbed tank plus 2 zone CH thermostats and HW.
• No primary circuit water connections whatsoever connected to tank

• incoming main connected to incoming control valve
• hot flow from tank connected via new pipework to en suites, bathroom and kitchen. Water heated via immersion only connected by electrician.

- Copper pipework (3m) installed from boiler site to adjacent to tank

QUESTIONS

I need to get a new boiler installed at the site of the old boiler in downstairs utility. Gas supply exists but new hole for flu required. Electrics installed by electrician . Boiler needs connecting to copper primary to tank and connecting to tank in airing cupboard.

Secondary expansion is connected to incoming control unit but primary expansion although in situ is not connected at all.

I am trying to get someone local to do the whole job but am thinking of the Gas Safe and G3 done separately.

1 I can get a boiler installed and connected to primary pipework but is that sufficient for the Gas Safe certificate or does the whole primary need to be there for certification.

2 Same with the tank

It does seem to be making the whole thing more complicated

I am happy to disconnect everything from the tank and balance the central heating etc. I am also happy to get someone in later to balance the whole system.

If I can I will get someone to do both but if not do i have any options re Gas safe and G3.

Thanks

Brian

It's probably best you get an engineer that can do both, and shouldn't be hard to find. Most have G3 now.

EvilDrPorkChop said:

It's probably best you get an engineer that can do both, and shouldn't be hard to find. Most have G3 now.

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Agree, just get someone in to do the lot.

The boiler will need to be connected to something to commission it.

I assume you had tanks in the loft and are now switching to unvented.

You mention en-suite and main bathroom, I hope you’ve been correctly informed that it’s highly unlikely you’ll be able to run more than one shower direct from mains through the unvented.

If you previously had tanks in the loft and pump/s, your experience with the unvented will likely be worse.

Saying that, there are some places with good mains flow rates to allow multiple showers on an unvented.

Have you tested the flow rate/pressure of your mains supply?

Timmy D said:

Agree, just get someone in to do the lot.

The boiler will need to be connected to something to commission it.

I assume you had tanks in the loft and are now switching to unvented.

You mention en-suite and main bathroom, I hope you’ve been correctly informed that it’s highly unlikely you’ll be able to run more than one shower direct from mains through the unvented.

If you previously had tanks in the loft and pump/s, your experience with the unvented will likely be worse.

Saying that, there are some places with good mains flow rates to allow multiple showers on an unvented.

Have you tested the flow rate/pressure of your mains supply?

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Depends on the water mains if it’s dynamic at 3.5 bar and 30lpm you could run two easily

ShaunCorbs said:

Depends on the water mains if it’s dynamic at 3.5 bar and 30lpm you could run two easily

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I get that, but I rarely come across 30lpm. They mention a bathroom and en-suites, so I assume 3 showers minimum.

I’m just advising that if they’ve been told the system will run it all at once, it’s unlikely.

If they get 30lpm, great.

My pal just had a sprinkler system installed direct from the mains. Was told it would be fine....He’s got 15lpm without the neighbour running water on their shared mains...
If someone installing life saving equipment can sleep at night in that scenario....

Timmy D said:

I get that, but I rarely come across 30lpm. They mention a bathroom and en-suites, so I assume 3 showers minimum.

I’m just advising that if they’ve been told the system will run it all at once, it’s unlikely.

If they get 30lpm, great.

My pal just had a sprinkler system installed direct from the mains. Was told it would be fine....He’s got 15lpm without the neighbour running water on their shared mains...
If someone installing life saving equipment can sleep at night in that scenario....

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Isn’t it off it’s own mains ? As that’s a requirement

ShaunCorbs said:

Isn’t it off it’s own mains ? As that’s a requirement

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Didn’t have its own supply. The guy connected onto the shared (lead split between 2 properties).

Last line in t&c’s states it’s the owners responsibility to ensure the system has 100lpm. Installer said he installs loads of them like this....where’s he getting 100lpm in most of his installs.....

We ended up installing a 1000L tank and booster pump which doubled the original cost of install.

Sounds like he’s a bodge as it’s water regs for own supply

I get around 2.5bar and 20/25lpm and can run two showers at once.

@ShaunCorbs Do you know the relevant info on that - sprinkler systems (I assume you're referring to garden) for bedtime reading. I just run mine of my main

EvilDrPorkChop said:

I get around 2.5bar and 20/25lpm and can run two showers at once.

@ShaunCorbs Do you know the relevant info on that - sprinkler systems (I assume you're referring to garden) for bedtime reading. I just run mine of my main

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Fire / emergency sprinkler systems eg the fun bulbs of wet events

ShaunCorbs said:

Fire / emergency sprinkler systems eg the fun bulbs of wet events

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I knew the fire ones had to be, we've done a couple of dentists with them. Although the fire sprinkler companys work was questionable