Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous showers

[woking]

Hi Guys,

I am hoping to get some advice from you to know what to ask my heat engineer to design / install.
The aim is to have enough hot water to run two showers simultaneously without use of unvented cylinder. I am planning to move boilers to the low pitch loft (second floor) and could not fit decent vertical unvented there. There is also a bit of work be needed to reinforce the loft to accommodate large cylinder. I have Greenstar 24 System boiler that I could re-use as a system boiler and install high performance hot water only boiler or possibly replace it by two 42CDi.

Here are options I am considering please let me know if there are any other high flow water only boilers I should consider:
1. Greenstar 24 System + Greenspring CWi47
2. Greenstar 24 System + Rinnai Infinity 26i
3. Greenstar 42 + Greenstar 42
4. Greenstar 42CDi + Greenspring CWi47

Have any of you installed / had any feedback from people using first two boilers or similar setup to option 3?
I am planning to upgrade gas supply pipe and getting U16 meter and also replacing current water mains (30 meters run from outside stopcock to the house) with 2 X 32MDPE water mains with the view to achieve decent water flow / pressure and be able to use one of the above setups.
I recently got waterboard to replace my old and rusty water meter and measure flow/ pressure. They said at the meter (about 30 meters from the property) I have 40L/ flow and 2.75bar.

Any thoughts or advice would be much appreciated and I hope not to cause too much controversy :smile:

 

[albatross]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

Simple and best solution: Keep the 24 system boiler to do the heating and fit a Rinnai HDC1600i to do the water 37 l/min
Rinnai HDC1600i continuous instant hot water boiler & flue & controller. | eBay

Ideas 1 & 2 =good in principle but hot water flow not amazing for the money paid,hence my idea.
Ideas 3 & 4 =poor ideas, low flow rates,expensive, problems altering/separating pipework, you can't link two combis together on hot water side, it won't work. No heating when hot water is used. Why buy two boilers when you already have one good one. If a combi breaks you loose everything. Combis have harder lives. If you have separate heating and hot water boiler have easier lives, less parts to go wrong and less upset if one does.

 

[woking]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

Thanks albatross,

This would probably best option. Have you heard any feedback from the customers who use 1600i? Are they getting very good flow while using two showers at the same time? Are these easy enough to install / maintain?

I could not find any reviews for 26I in the UK and seen some mixed from Australians.
I guess I could keep options 3 and 4 as backup in case I do net get 30+ L/m from my new watermain.

 

[albatross]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

Forget 3 & 4. It will never work properly, no one is likely to agree to do it for you and it's a waste of money.Stick to 1&2 if you don't get the water main.

All Rinnais are easy to fit. They are Japanese, high quality worldwide and have been around for decades. You won't see many reviews, they get fitted and work, people like giving bad reviews faster than they give good ones, they are a commercial product (meaning engineers don't do reviews, word travels in the trade, only homeowners with time on their hands do reviews) and in the Uk we all historically store water or have combis. They are increasing in popularity in larger properties for obvious reasons. If you only get 20+ l/min my idea is good, it will be very responsive and have an easy life, never work hard and last longer.

 

[woking]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

Thanks, that sounds promising.

I like Japanese stuff. Are they actually made in Japan?
It there official place to buy them in UK? Will the one on your link have any warranty?

 

[albatross]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

Made in Japan, 100 year old company, office/distribution in Runcorn. (shipped in to Liverpool docks). I have dealt with them for over ten years, a helpful company. Yes it brand new, boxed with flue and controller and full warranty. [DLMURL="http://www.rinnaiuk.com/warranties/"]Rinnai - Warranties[/DLMURL]

 

[Rickster123]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

Haha this thread reads like a scripted sales advert!

 

[Rickster123]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

And it's you who's selling it! Hahahaha genius!

 

[albatross]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

I don't know what you mean AP, I'm just providing excellent impartial advice about an outstanding product that would be perfect for the job. Any similarities between me and the sellers name, location, job, address, attractiveness and girth are purely coincidental!

 

[oz-plumber]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

RE: Rinnai continuous flow hot water.

Done hundreds of Rinnai and similar brand / type HWS.

The quoted figures for flow are at a 25C temperature rise, so technically speaking, if your cold water is entering at 5C, you will get 26 l/m at 30C.

From Rinnai Hot Water Manual

25C rise - 26l/m, 30C rise - 21.6l/m, 35C rise - 18.6l/m, 40C rise - 16.2l/m, 45C rise - 14.4l/m, 50C rise - 13.2m
55C rise - 12l/m, 60c rise - 10.8l/m

 

[woking]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

Thanks for your input oz-plumber,

What do your customers say after using theses systems for a while?
Are they happy with performance and can use 2 showers at the same time if run off same heater in the winter and summer?

Does shower get lower flow if one more tap open?

I've just remembered that I did not actually like my Greenstar 24 as I could only have 3 on/off periods for heating and not able to use Honeywell controller I really liked in the property I used to rent. I was also told that it has aluminium heat exchanger I could not use water softener with it.

Would Greenstar 42CDi + Greenspring CWi47 or Greenstar 42CDi + Rinnai be a better option then?

Shower in en suit is currently electric and would need additional plumbing anyway.

I could then have Greenstar 42CDi supplying my en suit shower and heating (I've lived with combi boiler for 3 years and did not had any trouble with heating being off while taking shower) and Rinnai or CWi47 supplying hot water to second shower and en suit bath (which does not get used very often) and hot water for the rest of the house.

Would either Rinnai or Greenspring CWi47 be able to supply enough hot water that shower did not get affected if someone open one tap to wash hands?

Are Rinnai 1600i and Greenspring CWi47 have similar performance?
Greenspring CWi47 seem to be quite a bit cheaper and much easier to source..

 

[albatross]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

Any Honeywell controller should be compatible with your Worcester 24i. The person who told you that does not know what they are on about. Also there are many good Worcester controls to choose from that can do all sorts.https://www.worcester-bosch.co.uk/homeowner/boilers/wave-and-boiler-controls/current-controls
A 42 CDI has an aluminium heat exchanger too, as do many boilers. Just fill the system before the softener.

Unless you want to waste money there is no reason to throw away a good 24i and buy a 42CDi. The choice of controls and water softener issue are identical for both boilers.

Whatever system you choose logic dictates the more taps opened the more the flow is divided between outlets and hence less. You would have to do lots of calculations or tests to get an accurate answer. Your biggest issue may be the 2.75 bar which is ok but not impressive, it will be lower at your taps when they are flowing.

Rinnai and Worcester are equally easy to source. With either you can buy direct or via any merchant and get next day delivery anywhere in the UK. There is lots of stock in the UK, I'm looking at it!

Prices equal when you include flue and controller.
Rinnai HDC1600i continuous instant hot water boiler & flue & controller. | eBay

 

[albatross]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

Just had another thought, ignore my good advice, if you really want a 42cdi I have one for sale too!

What you need is a 42cdi and a Rinnai 1600!

 

[woking]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

Thanks!

I'll definitely keep you in mind when time comes to order new boiler(s).
or the moment I need to get my gas supplier / national grid to upgrade my meter / pipework to be able to use any decent gas water heater.

My idea for having 42CDi is to separate it from other shower and run on separate cold water mains from Rinnai. I hope it will allow me to have combined water flow rates: HW from Rinnai+HW from 42CDi.

I am just thinking when the flow of shower decreased when another tap is run is it due to lack of hot water or could it be due to insufficient supply of cold water?

 

[albatross]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

Alterations | National Grid

Alterations to supply | Northern Gas Networks
Supply alterations depending where you are in the uk.

 

[albatross]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

I am just thinking when the flow of shower decreased when another tap is run is it due to lack of hot water or could it be due to insufficient supply of cold water?

Valid point. You have to be realistic though, we do not live in a perfect world. You have limited space. The designs you are looking at will be the best you can get without moving house. Over thinking will create problems that are not really problems and have no realistic solution.

 

[albatross]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

Thanks!

I'll definitely keep you in mind when time comes to order new boiler(s).
or the moment I need to get my gas supplier / national grid to upgrade my meter / pipework to be able to use any decent gas water heater.

My stock will probably be long sold by the time that happens.

 

[woking]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

I guess I would have to wait for my new water mains and test flow / dynamic pressure before making final decision on set-up. I could potentially put unvented where current cylinder is (and solve quite a few issues) but I would really prefer to use that space to make family bathroom bigger and empty loft seem to be such a waist of space...

Would I loss a lot of mains water pressure by moving my boiler from ground floor kitchen to the loft?

 

[woking]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

Good advice will never expire

 

[albatross]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

I guess I would have to wait for my new water mains and test flow / dynamic pressure before making final decision on set-up. I could potentially put unvented where current cylinder is (and solve quite a few issues) but I would really prefer to use that space to make family bathroom bigger and empty loft seem to be such a waist of space...

Would I loss a lot of mains water pressure by moving my boiler from ground floor kitchen to the loft?

In your situation unvented won't give you any better pressure or flow than what you are thinking of or what your water main can give you. So the result would be the same here.

Pressure is determined by to height of the outlet (shower head) not the boiler. A shower in the basement will be more powerful than one in the loft. Boiler position is pretty negligible. Longer pipe runs add resistance and reduce pressure but this can always be overcome with correct pipe sizing.

 

[woking]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

Alterations | National Grid


I was planning my U6 meter moved from the garage to outside wall and considered only available option to be Unvented which would need quite a bit of work in the loft. I though that upgrading my meter to U16 will be very expensive as incoming 30+ meters of gas mains would also need to be upgraded. After chat with National grid surveyor yesterday it seems that I would not have to pay for upgrade part of the work. I would only have to pay for the meter move.

That’s why I started considering option of separate water heater in favour of Unvented. As with water heater option I should not run into risk of running out of hot water and no complicated loft rearrangement will be needed.
According to surveyor from NG I need to speak to my gas supplier and ask them to upgrade my gas supply meter as l am planning upgrade to my heating system.

 

[woking]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

In your situation unvented won't give you any better pressure or flow than what you are thinking of or what your water main can give you. So the result would be the same here.

Pressure is determined by to height of the outlet (shower head) not the boiler. A shower in the basement will be more powerful than one in the loft. Boiler position is pretty negligible. Longer pipe runs add resistance and reduce pressure but this can always be overcome with correct pipe sizing.

That's good to know that I can move my boilers out of the way without loosing too much pressure. Should I then request that cold water run via 28mm pipe to the boilers in the loft of would 22mm be sufficient? My 32mm watermains will be ended by 28mm lever valve.

 

[albatross]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

Better to be bigger (28) and not need it than smaller and disappointed. Do the job right once. It's cheaper than doing it twice. It seems crazy to pay for a 32 main then let the job down by restricting it until you need to.

 

[woking]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

That is exactly my attitude. I would rather prefer to have a bit of overkill (I call it future proofing) then not have enough and having to re-do the job or having to put up with consequences...

Can I ask for another bit of advice? If I install 42 CDi can I setup two separate heating zones for upstairs / downstairs with two separate controllers? Does this normally require a lot of additional pipework = high cost?

 

[albatross]

Re: Greenspring CWi47 VS Rinnai 26i VS 2X Greenstar 42CDi for two simultaneous shower

Can I ask for another bit of advice? If I install 42 CDi can I setup two separate heating zones for upstairs / downstairs with two separate controllers? Does this normally require a lot of additional pipework = high cost?

You could. The ease depends totally on how your existing heating is piped up. Imagine there is one circuit downstairs, two pipes leading to upstairs and another circuit= easy to split. You would have to use Honeywell controls as Worcester controls can only do one zone. You'd need 2 zone valves too.

On the other hand if there is one circuit upstairs branching off to every radiator in the house that could be a nightmare to separate=lifting all floors and running a new circuit, many pipes to cap and rejoin, joists to cut. Lots of houses out there have systems that have been added to and cobbled on over the years so you may be looking at the unknown.