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Nice meeting you Dave today, and would just like to pass on the results from the install of a combisave at my mothers house.

Test before the install. At the kitchen tap just under 8l of water flowed into a bucket before the temp reached 40c, the same was recorded at the bath.

After fitting, we tested again and just under 4l of water flowed into the bucket and the water was noticeably hotter quicker getting to 45c.

The combisave had to be adjusted because the brittony se80 would not fire at 2.5l per min. and would have saved more water if it had.

Eco


im impressed with the results already, sounds like a good product
 
TBH i am not no ones heard of a ballofix??????????

It has a wax cartridge and works like a thermostatic mixer how can a ballofix do that GM as soon as it senses the 45c temp it slowly opens and closes to keep the set temp (ADJUSTABLE) a ballofix can only restrict the flow
 
It has a wax cartridge and works like a thermostatic mixer how can a ballofix do that GM as soon as it senses the 45c temp it slowly opens and closes to keep the set temp (ADJUSTABLE) a ballofix can only restrict the flow
ok fair enough if i get sent a free one i will stick it on the performa at home see how it fairs if it works i will specify it
 
It has a wax cartridge and works like a thermostatic mixer how can a ballofix do that GM as soon as it senses the 45c temp it slowly opens and closes to keep the set temp (ADJUSTABLE) a ballofix can only restrict the flow

Hi Eco

Is the wax cartridge easy to replace,is the part available,how much is it,out of interest
 
Hi Eco

Is the wax cartridge easy to replace,is the part available,how much is it,out of interest
did you have a nightmare at night puddle,i can see the cold sweats now 2 posts and potterton and wax cartridge mentioned that pumas coming to get ya
 
dave has kindly offered to install one at my house next week, so watch this space as there will be another before and after comparison coming soon..............
 
Hi Everyone.

Regarding the wax capsules. We've asked the same question about it's life span and this was the answer from the Manufacturers Sales Rep last year. Quote:-

"​Yes, I can offer some advice, interesting that everybody is an expert on wax elements, I'd like to know where his knowledge came from!

Yes, the wax will deteriorate over thousands of cycles (not time), about 80,000min to be exact! Elements have a reduction of stroke over a period of strokes (a long period of time) and are tested in all applications. A conservative life would be around 80,000 but it is not uncommon for 150,000 cycle to be met under endurance. Let's say the tap was used from full cold to hot 10 times a day, every day, that's 22 years!

On top of this they do not just stop working after this time, they actually lose some of the stroke, around 0.4-0.5mm so the element opening is affected, not whether it will work of not. If the stroke is shortened then there could be a reduction in flow for the reduced movement of piston. In this case a user may choose to reset the valve setting for a higher temperature to get greater stroke by increasing the water temperature, therefore over-riding the loss of stroke of the element............or buy a new element.

I hope this adds some meat to the bones for your 'expert'

It's worth adding that as the best, most-qualified producer in the World, Vernet have the best manufacturing facilities to give the best, most accurate and longest lasting performance over the life of the element. Wax mix, wax ingredients (wax and copper powder), process control, calibrating etc etc all lead and contribute to the element quality.

Maybe he is looking at the performance of 'non-Vernet' products".


OK, as you can see he's pretty passionate about his wax capsules. But the CombiSave has an adjuster to compensate for any changes. So we feel that it should have a very long lifespan. It is too early to say that we would sell the capsules separately but if there is a demand and of course, it is a greener thing to do, then I am almost certain that we would do that especially the way the price of Brass is going.
Cheers

Dave

 
Hi. You may be running with your preheat on which means that the boiler is keeping it's self permantly warm. Some Boiler manufacturers have fitted this function due to the problem of the delay of delivering warm water. This function costs you around ÂŁ75-ÂŁ150 per annum in gas even when your out. The combisave delivers a similar performance but without the cost.
The low flow rate is 2.5litres per minute is for only around 0-15 seconds, with an average saving of 5-6 litres and around 15 seconds quicker in getting to temperature. The bucket test of a before and after will prove this when one is fitted.
Please wait for the reports from the plumbers/Heating engineers on this Furum.
Cheers

David Furlong
Thanks for your reply to my post, #26, I am not a plumber but I have a science degree, a masters degree, and a Maths A level.
I had read the study on your website and the results of your tests do not support buying this product, but I may have missed something and I am happy to be convinced.

FYI I have a Rehema Advanta plus in my house. We normally fit Worcester Bosch combis. I have lived in houses previously with Vaillant, WB and Baxi combis with no complaint about any of them.

A plumber of heating engineer is not the right person to answer the simple question of whether your product is worth it.
Your website should be able to do that.

Is your product worth it? I see it as a basic maths question and on your website you have a long and detailed Report by Knowles & Green dated 2010 which describes a study based in a test house.
I doubt if many heating engineers are going to read it the report:
1. unnecessarily complicated
2. Does not address the simple question
3. And my reading of it does NOT support buying your product.

The Knowles/Green test had a tap at the end of 7.3 mtr & sjower at the end of 15.5 mtr of 15mm copper pipe. Obviously the water in this pipe is not hot and could be anywhere between hot and room temperature.

There is about 2.5 ltr of cold water standing in the pipe to the shower and just over 1 ltr going to tap. The test was done at various flow rates, note at 6 ltr pm to tap the cold water would take 10 seconds to clear the tap before we get water from the boiler.

In my experience this standing water can be a big inconvenience to people but can be a bigger problem for stored hot water when that store of water is a long way from kitchen tap and only a small amount of hot water might be required for washing up but the tap has to run for a minute before hot water arrives.

Section 3.2 of the report says that in real life hot water is probably useful after a rise of 30 degrees and you are basing your claims for the Combisave on flow rates of just over 9 lpm at the tap and the shower, this seems reasonable to me.

In the Knowles Study (I wish I could cut and past it, but I can’t):
(3.3) at temperatures below 35C combi save restricts to 2.5-2.8 lpm and combisave is ineffective.
And it is quicker to reach a 15C rise without comb save than with it.


Figure 3 seems to show that combisave is making very little difference at low flow rate of 3.7 ltr p m

Figure 4 flow rate 6 lpm 15C rise faster without combisave and at 6 lpm at combisave is not worth it even when you compare 30 degree rise.

When we get to Fig 6 with 9+ ltr pm the report claims Combisave is worth having. A 30 degree rise will be reached about 20 seconds fast with combisave at this flow rate but surely all the other data already given shows that the tap should not be turned on full until required temperature is reached.
Furthermore, quite a lot of the data in this study suggests it would be BETTER not to have combisave and just to turn the tap or shower on low flow rate of between 3 and 6 ltr per minute.

One further point: what is the flow rate of taps & shower in a house? I know typical low flow shower rate is about 9 ltr p m but it can be lower. I don’t know what flow rate is typical for taps but of course if the house has low flow taps throughout then combisave would be useless.

I believe WB & Vaillant dominate the combi market and I expect somewhere in their technical data they can tell us how long it will take any boiler to reach given water temperature rise at a specified flow rate. I think we are talking about seconds. So as I said this a solution for a problem which doesn’t exist. The problem is all the cold water sitting in 15 mtrs of pipe.
 
Mrs TP I am "only" a plumber/heating engineer but I had no difficulty in reading or understanding the report thank you.
 
I disagree Mrs Tara, the standing water in the pipe will be the same before the product is fitted as it is after, its the time it takes for the hot water to reach the tap that is the difference. Plus I'll let you know my results when I meet dave in the next week or so to fit the product but you may not take them seriously as im only a plumbing and heating engineer so i cant answer the question
 
Mrs TP I am "only" a plumber/heating engineer but I had no difficulty in reading or understanding the report thank you.

I hope my post doesn't anything about "only" plumbers... but it does say people who are NOT trained in heating/plumbing (potential customers) can read it. Sorry if i offended you that was not intended.

I said, i think not many heating engineers will read the report - it is 15 or so pages, that wasn't meant to imply heating engineers wouldn't understand it. I think most people in any profession are busy, don't read all the reports & studies and just look for the bottom line. The bottom line given by combiserve is that their product will save water, gas & money at 9+ l p m as shown by their test.
 
I disagree Mrs Tara, the standing water in the pipe will be the same before the product is fitted as it is after, its the time it takes for the hot water to reach the tap that is the difference. Plus I'll let you know my results when I meet dave in the next week or so to fit the product but you may not take them seriously as im only a plumbing and heating engineer so i cant answer the question

Yes, thanks, i understand that.
I haven't got the report open on my PC now but it on the front of their website - top right I think. It does show the difference in time for HW with or without combisave & with or without CH. The differences are clearly illustrated in the diagrams which I refered to fig. 3, 4 and 6. From memory i think if dhw is at 9.1 l p m the rise by 30 degrees is 20 seconds faster with the combisave than without which looks impressive, but lower flow rates do not support the use of combisave in their study. This is what they are telling us.
Unless i have made a big error (which would not be the first time in my life!)
 
Hi Tara, I apologize for our web site but a new web designer will hopefully have the new one finished next month. You are right that there would not be much difference at lower flows with the combisave fitted but nearly everyone turns the tap on full with the lower 24 - 28KW boilers as they only give a flow rate of around 8-10 litres per minute. The CombiSave very accurately controls the flow down to 2.5 litres and up to maximum boiler output to maximize the warm up. It is what some people have been trying to do for years to speed up the water delivery but the CombiSave does it accurately every time whoever, whenever or whatever demands hot water. It also saves around the ÂŁ100+ of gas charges per year as you can turn off the pre heat due to the fact the CombiSave give a similar performance to preheat.
Just a reminder that it is a multi-award winning device, so some people in high places are backing it.
Cheers

Dave
 
Dave came to fit one at a house for me, before it took around 10 litres to get 38 degrees, when it was fitted it took around 5 litres. The time was basically halved I cant remember the exact times but from i think 58 seconds before to around 30 after.
The flow rate is adjustable and so is the temperature, both by turning a screw on the valve.
Its very easy to fit and will adjust to any pipe configuration.
Any competent DIYer reading this considering it buy one from the combisave website, easy to fit yourself.
I'll be recommending it, already going to fit one at another house, it basically halves the water bill if on a meter, and obviously saves on gas at the same time. Some might think its a bit expensive at the minute but it will only take a year or so at the most to pay for its self and will last for 20+ years so cant loose
 
got me a new combisave valve installed courtesy of Dave.
results are as follows...

pre combisave time taken to get hot water at 45 degrees from hot tap = 31 seconds
post combisave = 26 seconds


pre combisave volume of water wasted prior to 45 degree water delivery = 5 litres
post combisave = 2.5 litres

obviously my boiler was performing better than those in the above tests however, even though my water saving was less in terms of volume, when expressed as a % it is still 50% which is pretty impressive.
on water savings alone it will pay for itself in 18 months, but the 5 seconds less delivery time from boiler ignition to delivery ensures that additional savings will be made on gas also.

all in all i have to say i'm pretty impressed with the whole thing, it is easy and quick to install, solidly built quality valve from a manufacturer with a proven pedigree, and offers RESULTS.

i will definitely be recommending this product to my customers.

KJ
 
dave has kindly offered to install one at my house next week, so watch this space as there will be another before and after comparison coming soon..............

Have just heard Radio 2 expounding virtues.
The same savings and performance can be achieved by only half opening hot tap, thus savings of ÂŁ95+ !!
With a bit of thought you can easily achieve this practice.
 
The kiss of death hangs over this product. BG are now fitting em lol

Sent from my GT-I9100 using Tapatalk
 
That's partly right, but no one can do it precisely-ever. Nor can you teach everyone in the house or possibly your washing machine to do it every time. In the same mind of thinking you can throw away your TV remote controls to push the buttons on the telly and your car and use your bike again as this will still get you from A-B... but not as good!!!
Cheers
 
Why on earth are they not fitted to boilers as standard?
 
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Hi Portishead,

There are a number of manufactures looking at the CombiSave at the moment as it is also designed to be installed during the manufacturing process. Potterton tried something similar back in the 90's but it was a bit of a complicated affair.
Hope that answers your question.
Cheers

Dave
 
I like em. My wife found it infuriating at first and i must admit i still shout at the tap occasionally 'give me some bloody water' but on the whole pretty good.

Sent from my GT-I9100 using Tapatalk
 
Hi Portishead,
This type of valve with a wax capsule and spring were fitted to all potterton puma combi's as standard over 20 years ago when water meters were first installed down south!
Re-inventing the wheel springs to mind.
I still service some of these boilers and they are going strong.
 
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