G3 unvented training.

[Ben-gee]

Having recently fitted three Monsoon 3 bar pumps, two universal, I found myself thinking I would like to be able to offer my customers the alternative of fitting an unvented cylinder. These pumps are superb but quite costly (note I don't say expensive as I think they are good value) and inevitably have noise which is not always ideal.
Does anyone know of a good course, possibly manufacturer's?

 

[Best]

I just went to a local training center.
Well worth doing because you can then also service and repair unvented units.
Probably about a day at most to do the qualification.
A lot of it will be to do with the various controls functions, the combination valve components and expansion vessel order of parts before linking to cylinder, plus the D1 and D2 regs and termination points.
As you say, all pumps, including even the excellent Stuart and Turner pumps, are noisy. Unvented cylinder often cheaper.

 

[Ben-gee]

Thanks Best. So I take it that the installation is not too difficult to do, obviously there is a need for safety and I guess the G3 registration is an attempt to keep the mouth breathers away from this.
What are the lower limits for pressure and flow requirements in your opinion, I guess this will be covered in any course but I'd be interested to know. A lot of properties around here are under 2 bar and around 15l/min.

 

[Best]

The course from what I recall, wasn’t that practical in giving advice.
My first G3 qualification had no training really.
Ideally you want 3 bar or more static pressure and 20 litre or more flow rates. Most stainless steel units operate on 3bar mains inlet pressure on their combination valve PRV.
2 bar is still possible but you need to check what dynamic pressure is.
I read that 1 bar dynamic is the lowest acceptable.
Luckily any I have done have decent flow & pressure.
Another thing to consider is the peak demand times on the local mains supply.
Taps are restrictive, so remember the flow rate will be greater from an open pipe, even compared to garden tap.
Ideally the mains pipe to a property should be more than 15mm.
It also depends on size of property - if several bathrooms and occupants obviously. That is where a pump can be best.

 

[Ben-gee]

So unvented in not the panacea some people seem to say. I guess you have to be careful the mains can cope with demand once all cold and hot outlets rely upon it.
I have a customer running an unvented cylinder where this is supplied from a cws tank via an ST monsoon. I'm unsure why, is this better than pumping the outlet from a regular vented cylinder? I suppose the pump is only handling cold water so may last longer, less scale?

 

[Best]

So unvented in not the panacea some people seem to say. I guess you have to be careful the mains can cope with demand once all cold and hot outlets rely upon it.
I have a customer running an unvented cylinder where this is supplied from a cws tank via an ST monsoon. I'm unsure why, is this better than pumping the outlet from a regular vented cylinder? I suppose the pump is only handling cold water so may last longer, less scale?

I think you are right. Obviously the mains wasn’t up to the job.
I would have just used a twin Monsoon on a vented system though.

 

[Welder]

Best is spot on. The course gives you the ticket, but that's just the start really. FWIW, I'd then talk to your reps. The best by a country mile in my opinion is OSO. Our guy is David Wilks. Bless him he's a real font of knowledge, totally honest in that he'll tell it as it really is and happy to accompany you to site when you need more experience to apply to a job.

It IS possible to fit under your circumstances, but most times you'll need either an accumulator or a seperate (hi capacity) break tank and pump to supply the building. Done these a few times and they work really well - provided they are designed correctly.

 

[SimonG]

Turned up for my g3 at 8.30. 45 minutes wasted doing admin. Bit of theory. Into workshop to look at installs. Cup of tea. Bit more theory. Multiple choice open book exam. Back in the van for 12.00. Two hundred notes lighter. Then 120 to add onto my ofeck.

 

[SimonG]

What really grates me is that if people actually took the time and read the installation instructions and then followed them there wouldn't be an issue.
Still, I make a Bob or two putting stuff right

 

[Ben-gee]

Where was that Simon, i'd hoped it would be more involved than that! I'm considering Heatrae Sadia £175, supposedly get it back when you purchase a cylinder; or Gledhill, on offer at the moment for £90.
I'm guessing that like most of these things, having the ticket won't help a bit when you come across an unusual situation - I suppose that's when the black book comes out and you have to put up with the ribbing from more experienced pals.
I think I'll go for it and then on first couple of installs I'll give the job to someone else of the proviso that I can tag along and ask plenty of "but why", "what if it was.." type questions

 

[SimonG]

Up at Cramlington.

 

[Ben-gee]

Ah OK that's miles from me. Just looked it up as didn't know, near Newcastle, and ridiculously I could get a return flight from Bristol - Newcastle (and back) for £64 and it only takes an hour! Imagine that journey in a van at 30mpg at diesel prices today, none of this makes any sense to me.

 

[Jim Goodenough]

Maybe a bit off topic... has anyone installed a ScubaTANK before? ScubaTANK WX - WRAS Approved In-tank Booster Set

I've recently quoted a customer for installing one, they have an unvented cylinder with poor water pressure.

 

[ShaunCorbs]

i believe @Chalked has

 

[Welder]

Done something very similar. Hence the prev post.

 

[Ben-gee]

Dave, how would you chose between accumulator and pumped break tank? Is it a question of space only? I imagine an accumulator in much quieter if the set-up has to be in a "domestic" part of the house, assuming I am right in thinking it is a sealed storage tank with a bladder in it. For either option - how does one calculate the size of tank needed.

 

[ShaunCorbs]

Dave, how would you chose between accumulator and pumped break tank? Is it a question of space only? I imagine an accumulator in much quieter if the set-up has to be in a "domestic" part of the house, assuming I am right in thinking it is a sealed storage tank with a bladder in it. For either option - how does one calculate the size of tank needed.

Specs for accumulator Min

2-2.5 bar and around 15lpm, capacity wise double up as you will only get 50% of the volume so you have a 200 l unvented cylinder you will require a min of 400 l of accumulator volume

Break tank and pump anything below what you require but depending on how the mains is you might want to add stored capacity e.g. If it's only 1 bar and 5 lpm I would work out what you need at max draw and time to refill

 

[Ben-gee]

Thanks Shaun; so too low pressure or flow rate can only be sorted by break tank and pump, not by accumulator?

 

[ShaunCorbs]

Thanks Shaun; so too low pressure or flow rate can only be sorted by break tank and pump, not by accumulator?

Correct accumulator won't boost the pressure

 

[Ben-gee]

So accumulator just fitted to mains with regular T, goes into and out of accumulator via same fitting - i.e. it just boosts flow.
Only way to boost pressure is via a pump, I think I'm getting it now.

 

[Ben-gee]

Although I suppose accumulator could "over pressurize" during night time spikes in mains and therefore be stored at higher pressure than the main usually supplies - albeit for a very shortlived time once it started to flow back out.

 

[ShaunCorbs]

Need a check valve on the supply but yes

And a tiny bit but nothing the system isn't used to

 

[Chalked]

Maybe a bit off topic... has anyone installed a ScubaTANK before? ScubaTANK WX - WRAS Approved In-tank Booster Set

I've recently quoted a customer for installing one, they have an unvented cylinder with poor water pressure.

I’ve fitted a few. They are the best by far. Not much noiser than a fridge, as the pup is submersed in the storage tank. Pump is full stainless steel. Inverter control, to give seamless water pressure, without the kick in of normal pump, with pressure switches.
If your after nearly as good, DAB esybox is excellent too.
Not that I need one. But if I did, I would use the Scubatank.

 

[Jim Goodenough]

I’ve fitted a few. They are the best by far. Not much noiser than a fridge, as the pup is submersed in the storage tank. Pump is full stainless steel. Inverter control, to give seamless water pressure, without the kick in of normal pump, with pressure switches.
If your after nearly as good, DAB esybox is excellent too.
Not that I need one. But if I did, I would use the Scubatank.

Dutypoint now sell unvented cylinders with 1" CF & DHW draw off which come in handy for larger properties.

 

[ShaunCorbs]

Dutypoint now sell unvented cylinders with 1" CF & DHW draw off which come in handy for larger properties.

they look a decent bit of kit upto 500l not bad coil cap and under an hour reheat

 

[Chalked]

they look a decent bit of kit upto 500l not bad coil cap and under an hour reheat

Up to 6 bar working pressure too.
I’ve got an account with them. So might get a price.

 

[ShaunCorbs]

Up to 6 bar working pressure too.
I’ve got an account with them. So might get a price.

if you dont mind let us know the rough ball park

 

[Chalked]

if you dont mind let us know the rough ball park

Will do shaun.