I've provided a lovely new cold feed going exclusively to a new combi. A quick question.

[Mr.B]

Your shower will get it's hot water from the boiler ,and a little cold will be added to achieve your desired showering temperature.

I have to perfectly honest and say I hadn't, in all this time, appreciated the obvious, realistic point you make there. I, mistakenly, kind of saw the hot and the cold doing battle with each other with similar force and in similar quantities and any minor reduction in either supply having a significant effect. It's not uncommon to see reports of showers going cold or scalding hot coz someone flushed the loo or washed their hands in cold water. But the image you've created of it being mainly hot with just a smidge of cold to make smallish adjustments does rather put things into prespective. I have had almost no direct, practical experience of using half decent, recent combis and hope not to be disappointed when it eventually happens. I'm placing quite a bit of faith in a 32kw Vogue and its apparently respectable components within and realise it has it's detractors ... but they all seem to.

We shall see.

Thanks.

 

[martygturner]

Personal I wouldn't panic .. we run two showers off a greenstar 1000 both are warm at 50 degrees.. The thing we found was adding a small pressure vessel to the cold feed after the one way valve sorted out any flow issues. Just made the cold feed stable..

 

[Mr.B]

Personal I wouldn't panic .. we run two showers off a greenstar 1000 both are warm at 50 degrees.. The thing we found was adding a small pressure vessel to the cold feed after the one way valve sorted out any flow issues. Just made the cold feed stable..

I already planned to fit a pressure reducing valve (as I mentioned in a previous reply) but that's not what you're saying.

As it happens I was going to ask the installer whether it's advisable to fit an expansion vessel to the heating circuit as there's 15 rads (albeit not huge ones) in order to supplement the expansion vessel in the combi.

But I hadn't given any thought to .... adding a small pressure vessel to the cold feed after the one way valve sorted out any flow issues. Just made the cold feed stable ....

** But which "one way valve" do you refer to? I don't think I knew there was going to be one ... or do you mean one that might be fitted at the water meter?
** And when you say 'small pressure vessel', do I take that to mean an expansion vessel? I'd be fascinated to know how or why the vessel you
speak of sorts out any flow issues. And how small is "small" ? This new to me and I'm keen to learn.

 

[Johntheo5]

Your shower will get it's hot water from the boiler ,and a little cold will be added to achieve your desired showering temperature.

I have to perfectly honest and say I hadn't, in all this time, appreciated the obvious, realistic point you make there. I, mistakenly, kind of saw the hot and the cold doing battle with each other with similar force and in similar quantities and any minor reduction in either supply having a significant effect. It's not uncommon to see reports of showers going cold or scalding hot coz someone flushed the loo or washed their hands in cold water. But the image you've created of it being mainly hot with just a smidge of cold to make smallish adjustments does rather put things into prespective. I have had almost no direct, practical experience of using half decent, recent combis and hope not to be disappointed when it eventually happens. I'm placing quite a bit of faith in a 32kw Vogue and its apparently respectable components within and realise it has it's detractors ... but they all seem to.

We shall see.

Thanks.

I think its a given that there wont be flow problems especially with a 7bar mains, the limiting factor will be thermal, ie, 32kw, if you use 10C as a standard for the mains temp and 40C for the required showering temp then 32kw will provide a flow rate of 15.28Lpm to one shower or with suitable restrictors installed, 7.64LPM to each shower to enable both to run together, not a bad flowrate if not quite power shower rates?

Regarding the EV sizing for your rads, some use a rule of thump of 1L per rad so a 15L EV but 10L should be OK, if you can give some indication of the total rads output, and/or size of the installed EV, can advise.

 

[Mr.B]

It was 7 bar when I moved in, as mentioned ...now 4 bar, as also mentioned - apparently as more houses were built in the town the water supply had more demand and the rate came down (unlike my Council rates, which go up). But I'm thinking 4 bar is plenty. I've reduced it to 3.5 bar with a PRV as referred to above.

I haven't attempted to work out what each of the 14 (plus one more due to be fitted in the airing cupboardwhen the cylinder comes out) .... radiators add up to but have gone round the house with a Mears Calculator and compared the readings from that wityh one or two online basic calculators - and have a figure of 13kw plus whatever the HW cylinder might add (but it's coming out anyway).

The Vogue exp. vessel is 10 litres. Although the system is a mix of 22mm, 15mm, and 10mm feeds to each rad.The rads aren't huge so maybe the system is under 100 litres? but I'm guessing. In fact, how does anyone work out the capacity of any system with any degree of accuracy?

The Vogue literature quotes HW flow of 13.1 lpm @ 35 degrees rise.

My current shower discharges 5 litres per min into a bucket (which is OK for us). In fact I have the little inserts that Ideal produce to fit into the shower hose to reduce the flow as and when a combi is fitted. Set of three reducers with varying flow restrictions. The Mira Excel cartridge has a switch on the back to alternate between High and Low pressure. I'll start off with it on High presumably.

 

[Johntheo5]

It was 7 bar when I moved in, as mentioned ...now 4 bar, as also mentioned - apparently as more houses were built in the town the water supply had more demand and the rate came down (unlike my Council rates, which go up). But I'm thinking 4 bar is plenty. I've reduced it to 3.5 bar with a PRV as referred to above.

I haven't attempted to work out what each of the 14 (plus one more due to be fitted in the airing cupboardwhen the cylinder comes out) .... radiators add up to but have gone round the house with a Mears Calculator and compared the readings from that wityh one or two online basic calculators - and have a figure of 13kw plus whatever the HW cylinder might add (but it's coming out anyway).

The Vogue exp. vessel is 10 litres. Although the system is a mix of 22mm, 15mm, and 10mm feeds to each rad.The rads aren't huge so maybe the system is under 100 litres? but I'm guessing. In fact, how does anyone work out the capacity of any system with any degree of accuracy?

A 10L EV with precharge and filling pressures of 1.0bar/1.5bar will suffice a system volume of 125L with a final pressure of 2.5bar even if the average of the flow/return temps are a unlikely 65C, the final pressure would still not reach 3.0bar even with a system volume of 162L,

The Vogue literature quotes HW flow of 13.1 lpm @ 35 degrees rise.

Thats correct but even if the flowrate through the combi is only say 10LPM at 56C, the remainder cold at 10C will still provide > 15LPM at 40C.

My current shower discharges 5 litres per min into a bucket (which is OK for us). In fact I have the little inserts that Ideal produce to fit into the shower hose to reduce the flow as and when a combi is fitted. Set of three reducers with varying flow restrictions. The Mira Excel cartridge has a switch on the back to alternate between High and Low pressure. I'll start off with it on High presumably.

 

[cdbe]

Keep the ideal classic and get an unvented cylinder. I'm constantly stunned when I go to my posh friends houses and I can't have a shower till someone else has finished or (more annoying) I have to wash my hands in cold water after I've been to the toilet.

 

[MNW67]

Personal I wouldn't panic .. we run two showers off a greenstar 1000 both are warm at 50 degrees.. The thing we found was adding a small pressure vessel to the cold feed after the one way valve sorted out any flow issues. Just made the cold feed stable..

How's the boiler overall? I believe it's a new model and the first WB with a stainless steel heat exchanger.

@Mr.B Have you considered it?

I think the heat exchanger is made by the same people who make the one in the Vogue, but with a large bore design rather than a small bore design.

 

[Mr.B]

How's the boiler overall? I believe it's a new model and the first WB with a stainless steel heat exchanger.

@Mr.B Have you considered it?

I think the heat exchanger is made by the same people who make the one in the Vogue, but with a large bore design rather than a small bore design.

I know very well that Worcester and Vaillant are the two names that constantly appear when discussions are conducted about which boiler to go for. I'm aware of drawback to all boilers but I don't have great feelings for either.. I looked long and hard at Intergas and, more recently, at Viessmann but both are less "mainstream" and it continues to concern me regarding availability of parts and repairers locally. I have a vague suspicion that Viessmann needs a bit more specialist knowledge to get the best from them and am afraid that the local(ish) fella (who I believe to be held in very good esteem) is a rarity and we would be dependant on his continued availability and also wonder what the spares situation genuinely is.

There are no local Intergas installers on the website and that hasn't changed for years and the Intergas proponents on here have gone very quiet on Intergas.

Lastly the well regarded, very local, installer that I favour has dropped Vaillant and is now only instals WB and Ideal. I shall check further about the Worcester 1000 you speak of but don't see that many criticisms of the Vogue and am happier to be dealing with a local trusted installer and a mainstream manufacturer. But nothing has been confirmed and I'm very happy to continue to listen to others.

 

[MNW67]

Lastly the local, well regarded, very local, installer that I favour has dropped Vaillant and is now only accredited to instal WB and Ideal. I shall ask further about the Worcester you speak of but don't see that many criticisms of the Vogue and am happier to be dealing with a local trusted installer and a mainstream manufacturer. But nothing has been confirmed and I'm very happy to continue to listen to others.

I've just had a look. It may have a shorter warranty than the Vogue. 5 years vs up to 12 years. Sometimes, though, I think the length you get depends on the installer. I'd be interested to hear what he thinks of it!

 

[Mr.B]

I did spend half an hour with YouTube and if I'm honest, apart from it having a big bore stainless steel HEX, it didn't do anything to make me change my mind about a Vogue.

 

[Mr.B]

I just found the thread in which a contributor recommended the course of action that I followed. But it wasn't on DIYnot, it was the Screwfix forum and it dated back to 2010 and it resulted in a dialogue in which another contributor ridiculed the plan but the proposer, who's advice I followed, stuck to his guns and they agreed to differ. He does say, however, take the cold shower feed from the dedicated "branch" rather than the alternative 15mm main feed supplying the rest of the house.

It has to be said the poster in question no longer posts on Screwfix Community ... he's long gone, or at least no longer uses the same nom de plume. His posts were a mix of seemingly sensible stuff mixed with a lot of controversial bickering and insults.

It could be we've answered my query and the matter should rest in peace.

Thanks again for advice received.

 

[martygturner]

I already planned to fit a pressure reducing valve (as I mentioned in a previous reply) but that's not what you're saying.

As it happens I was going to ask the installer whether it's advisable to fit an expansion vessel to the heating circuit as there's 15 rads (albeit not huge ones) in order to supplement the expansion vessel in the combi.

But I hadn't given any thought to .... adding a small pressure vessel to the cold feed after the one way valve sorted out any flow issues. Just made the cold feed stable ....

** But which "one way valve" do you refer to? I don't think I knew there was going to be one ... or do you mean one that might be fitted at the water meter?
** And when you say 'small pressure vessel', do I take that to mean an expansion vessel? I'd be fascinated to know how or why the vessel you
speak of sorts out any flow issues. And how small is "small" ? This new to me and I'm keen to learn.

On our combi it goes cold water feed, one way valve, limescale reducer (discuss merits - but boiler makers all seem to want one) small pressure vessel /expansion tank eg https://www.screwfix.com/p/ideal-heating-expansion-vessel-kit-0-16ltr/7292x = which is sepecced for the vouge.

The expansion valve stops any shocks keeping flow to the boiler consistent...eg a cold is turned on when a hot is on somewhere else.

As for the WB - its great all in including the flue its was £879 vat inclusive for the 30kw took our plumber 3 hours to fit + 1 hour for a system flush.

We already had a tado thermostat ,rad valves and a weather compensate ( - which I would highly recommend £40 + some flex- you can shove that on a north wall or any wall out side of direct sunlight).

By the looks of things a vouge runs in at £1500 for the boiler - really unsure what else you get for your money 5 years v 12 years except do you really - we have two viessamns in rentals both failed the pcb at 3 years - despite the cast in gold warranty we ended up paying for the boards - pls send us the board for repiar - ok how long will that take .2-3 weeks yeh right in winter- .. the insides of ours is well made - simple to service and has been totally reliable.

 

[Mr.B]

On our combi it goes cold water feed, one way valve, limescale reducer (discuss merits - but boiler makers all seem to want one) small pressure vessel /expansion tank eg https://www.screwfix.com/p/ideal-heating-expansion-vessel-kit-0-16ltr/7292x = which is sepecced for the vouge.

The expansion valve stops any shocks keeping flow to the boiler consistent...eg a cold is turned on when a hot is on somewhere else.

As for the WB - its great all in including the flue its was £879 vat inclusive for the 30kw took our plumber 3 hours to fit + 1 hour for a system flush.

We already had a tado thermostat ,rad valves and a weather compensate ( - which I would highly recommend £40 + some flex- you can shove that on a north wall or any wall out side of direct sunlight).

By the looks of things a vouge runs in at £1500 for the boiler - really unsure what else you get for your money 5 years v 12 years except do you really - we have two viessamns in rentals both failed the pcb at 3 years - despite the cast in gold warranty we ended up paying for the boards - pls send us the board for repiar - ok how long will that take .2-3 weeks yeh right in winter- .. the insides of ours is well made - simple to service and has been totally reliable.

All received, thank you.

I now see that what you refer to is known to me as a "Mini Shock Arrestor" as typically manufactured by Altecnic, Flomasta, Ideal etc.and is often apparently installed to prevent or to overcome water hammer and, as I believe you said, is specified for the Vogue although I haven't seen that specific requirement promulgated.

Your observations regarding Weather Compensation is duly noted - I have no experience of it and have yet to have any hands on familiarity with it.

With respect to the choice of a Vogue as opposed to a Worcester, I'm prepared to listen to all points of view, including that of the prospective installer (who is an Ideal MAX accredited installer as well as a Worcester installer) but am more inclined to go for what, I hope, is the best appliance in my particular circumstances rather than that which is less expensive. Having said that I must concede that a 30kw Greenstar combi is less than half the cost of a 32kw Vogue. I agree that's a substantial figure with which to conjur and could be viewed as a bitter pill to swallow.

I think you spoke of Viessmann boilers and of the disappopintment of having two fail on you. I can say at this point that I have, rightly or wrongly, discounted Viessmann despite a good many other opinions favouring their degree of performance, sophistication and apparent build quality.

I'm grateful for your troubling to relate you own experinces and perspective.

 

[DP]

An installer has suggested I shouldn't worry about leaks due to pressurising the 28 year old 10mm / 15mm /22mm copper small bore gravity system (Ideal Classic fitted in 1996) so I shall hope for the best in that regard.

Do you have overheat stat fitted to the classic?
So you do not have an expansion cistern in the loft but there is a cold water storage cistern ( unless you have got an unvented cylinder in which case you cannot have gravity heating of water in cylinder)

My question was, however, should I take the cold to the showers from my 'purpose made run' or take it from the 15mm that supplies the rest of the house?

boiler will supply 13 l per minute and no more. Cold into the boiler should be able to support that requirement. If not, boiler will still function but output flow will be diminished

My worry would be tightness of the heating side if present system is open vented.