The only thing about that is that it doesn’t have the flow rate of the 8000. So if I do have an occasion where two showers are on it won’t be as good presumably.
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32kw heating and 34kw dhw. I have 18 rads so is this not a tad light on the heating side?
This is what I thought I was just getting. So is 34kw dhw going to run two showers satisfactorily? Or do I need the extra 10 kw for when that situation arises?
More than that last time I checked _more like over 16lpm and doesn't require huge power requirements because of hex efficiency.
Do you have the gas supply/meter to even feed a 50kw combi otherwise you're wasting your time considering one?
I’m looking at the 45kw Max now and would get it checked obviously prior to install.
What would be great is a video of two showers running off of the various boiler outputs with the correct pressures and flow rates so that consumers know what the reality actually looks like.
Attachment above says 32kw to heating and 29.3 to HW, it doesn't matter how efficient the boiler is, if its output to HW is 29.3kw then you can only get 12 LPM continuously from 5C to 40C. If its a storage boiler, then depending on the store size you can 16LPM or higher but for a limited period, I would like to see how they arrive at this 16 LPM number.
If you have these energy saving showers installed which limits the flow rate to 6 LPM, then, yes, just about possible to run two showers, I would measure the shower flow rate as is and you can then decide, also remember even if you can install a 50 kw boiler (gas supply etc, as pointed out) which gives 20.38 LPM, you will then have to restrict the showers to 10 LPM even if only one in service to allow both in use on the rare occasions you require them, so measure the present flowrate which will decide things, one way or the other.
CH output is probably OK especially if you have zoning.
The reality is exactly (IMHO) as I have shown for the various boiler outputs, it cannot be otherwise. If you ran 5 showers off this ( 29 kw) boiler then the flow rate will be restricted to 2.4 LPM, each, not very pleasant.
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It is definitely impressive the flow rates large combis and storage ones offer.
My only consideration would be where do you go once they start to withdraw natural gas.(I appreciate that it may still be 10 yrs plus off.) Apparently other options produce considerably less energy and we may all have to look at stored hot water options and much more efficient homes. Just a thought, but may not be relevant on this decision.
My only consideration would be where do you go once they start to withdraw natural gas.(I appreciate that it may still be 10 yrs plus off.) Apparently other options produce considerably less energy and we may all have to look at stored hot water options and much more efficient homes. Just a thought, but may not be relevant on this decision.
Unless you had identical showers, flow and pressure in your home it would be pointless
If you have limited space, budget or are happy To live with its limitations go for a combi.
If not - boiler and unvented cylinder.
If you have limited space, budget or are happy To live with its limitations go for a combi.
If not - boiler and unvented cylinder.
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Current Viessmans
There's a 45kw Viessmann 200, it's semi commercial and almost double the cost of your WB 6000 at £3.5k but offers large flow rates.
All Viessmann 200 & 300's are H2 ready or basically ready to run on a part hydrogen gas mix.
There's a 45kw Viessmann 200, it's semi commercial and almost double the cost of your WB 6000 at £3.5k but offers large flow rates.
Couldn't attach a file so here are a few numbers that may help you to choose your combi.
| | | | | | | | |
| | | Continuous | | | Required | | Recovery |
Power | Mains | HW | Flow | | Stored Vol | Flow | Duration | Time |
Output | Temp | Temp | rate | | at 75C | rate | Period | to 75C |
Kw | DegC | DegC | LPM | | Litres | LPM | Mins | Mins |
30 | 5 | 40 | 12.3 | | 45 | 16 | 5.6 | 3.7 |
30 | 10 | 40 | 14.3 | | 45 | 16 | 6.1 | 3.7 |
| | | | | | | | |
35 | 5 | 40 | 14.3 | | 45 | 18 | 5.0 | 3.1 |
35 | 10 | 40 | 16.7 | | 45 | 18 | 5.4 | 3.1 |
| | | | | | | | |
40 | 5 | 40 | 16.4 | | | | | |
40 | 10 | 40 | 19.1 | | | | | |
| | | | | | | | |
45 | 5 | 40 | 18.4 | | | | | |
45 | 10 | 40 | 21.5 | | | | | |
| | | | | | | | |
50 | 5 | 40 | 20.5 | | | | | |
50 | 10 | 40 | 23.9 | | | | | |
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Over the last 2 months we have, at the customers request, installed 3 large ( 40kw plus ) combi boilers. Only one ( customer) is happy with the performance delivered.
I would add that none of the above are the WB 50kw offering, but only because the existing gas supply was not adequate
I would add that none of the above are the WB 50kw offering, but only because the existing gas supply was not adequate
On this basis I hope you can see my conundrum. I have had 3 different boiler engineer come to my house and tell me 3 completely different things, which is why I am researching it myself.
So based on the likelihood of limited gas supply (yet to be determined) would you suggest a storage combi, if sticking to a no tank solution?
What were the customers not happy with? Flow rates?
If you haven't got the gas rate ie the energy to heat the water fast enough then you won't get the HW flow rate, any engineer who suggests just sticking in a high powered combi without a gas meter upgrade should basically be ignored.
Why would you need a gas meter upgrade? A standard meter provides 6m3/hr gas. Providing there’s no other appliances or just a small one such as a hob then no upgrade is required.
Obviously your pipe work has to be correctly sized, but I don’t see an issue and I’ve personally never had any issues in requiring the correct gas rate.
The issue would be more with your incoming water supply, on 15mm pipe work. If you’re wanting to require the correct flow rates you should be running a 22mm water main to the combi and 22mm off.
It's tight isn't it, yes a G4 has max capacity of 6m3 but really it's 4m3 with loss plus as you say you'd expect other appliances to be online simultaneously. Also you can't dismiss Bramble's experience with installing oversized boilers using a standard domestic meter. It doesn't seem that you get the real world performance you hope and pay for.
From my experience it isn’t that you haven’t got enough gas, it’s that the water pressure and pipe sizing which won’t give you the required flow rates to even get the figures they suggest.
For instance we’ve fitted a 35kw combi in a refurb, we’ve done a 22mm water main and 22 to outlets @ 2.5 bar it easily does 15lpm to 55oc. If that’d been 15mm pipe work I doubt we’ve be even getting 12.
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