Looking at a replacement boiler prior to kitchen refurb and I see that Worcester Bosch do HE28 and HE29. The difference is, one is "system" boiler containing pump and the other "conventional" boiler without pump. Both I believe are condensing units so presumably meet the recent required standards. BUT The system boiler appears to be used on sealed systems only! Can someone explain why please?
I am improving (I hope) a 1970s build house. Is it likely that the system will be "sealable". What would make it unsuitable for sealing? I currently have Gloworm Spacesaver 50 and pumped S plan piping (with some naff modifications). I am replacing all rads with Drayton TRVs and Pegler Terrier lockshields (as I renovate each room).
Any recommendations on controls for whichever boiler is recommended?
Because that is what they are designed for. One box with all controls inside inc pump. A combi without the water section
Nothing. Some of the old rads may pop and need replacing because of the increased pressure. If they do they were on there way out anyway. Flush the system using Fernox system cleaner.
Try an Alpha CD50 stored water high flow combi. It will do your bungalow no problem as long as the cold mains is fine and fill a bath in few minutes. It has built-in by-pass, cyclone debris catcher, anti-frost too. No cylinder taking up space and all those troublesome valves hanging around making the place look like something from a Fed Dibnah show. Use a Honeywell CM67 optimiser stat/programmer, that decided when to start the heating in the morning to the temperature set point and time set.
Property is 4 bed detached, not bungalow, hence 29kw boiler considered - existing 50000btu model is struggling big style. Tending away from combis due to pipe routing headaches and demand from 2 bathrooms SWMBO and teenage kids!
That would mean major piping works! As the modern boilers modulate, is the 2 boiler approach justified (other than by the "only one service is lost in the event of failure" argument).
Hi Phil, As mentioned in another post, next week sees the replacement of my 24kw old boiler with a 40kw condensing boiler. Same size house I guess: 4 bedroom detached. The gas engineer that we got to give us some advice had a fit when I told him that in the last 7 years I managed to ADD twelve radiators to the existing eleven radiator system (!) Hence the need for a beefier boiler. No doubt the lack of the word "combi" will irritate the idiot...
Manufacturers have different ideas of what system means.
However, almost all of them agree that it will include a pressure vessel, pressure gauge, pressure relief valve etc. for sealed operation. Most (but not all) also include the pump and filling loop.
If the pipework starts weeping at the joints, then it wasn't suitable. However, this is just bringing forward the inevitable. You might as well have the leaks fixed now when the plumber is round, rather than letting them develop naturally and have them express themselves on the first day of your foreign holiday next year.
1970s plumbing would definitely have been designed for the pressure. Only faulty installation or serious corrosion will have let to them no longer being suited. Do note that during the copper shortage of the 1970s, pipes were made thinner and may not have their full longevity.
Any combi will do for heating purposes. The Alpha can do two shower no problem. It will fill two bath simultaneously a bit slowly, but one bath as fast as most cylinders. The recovery rate is minutes. Fill one bath leave 5 mins and fill another. When the internal store is depleted it reverts to normal combi flows.
I have a relative who fitted one on my advise when building an extension and an extra bathroom. After 3 months they have had no problems with three teenagers. They like the powerful power shower type mains showers. Fills baths pronto and have never had to fill two baths together. If so, wait a few minutes and it fills in a few minutes. It also heats the house up very quickly compared to the old boiler they had
If you are going cylinder then get a quick recovery as you can downsize the cylinder. This will reheat in minutes. Use two 2 port zone valves and have the system a priority system with DHW priority. Instead of a power shower pump have shower immersion coils. Two can be fitted in the cylinder as well as a quick recovery coil.
Nor so. The cheapest option, which will give greater longevity and save space and never runs out of hot water, is one of the new Japanese 2 bathroom instant hot water high flow multi-points. The Rinnai is "very" reliable, and is sold all over the world. Rinnai are the world's largest gas appliance maker, with typical Japanese quality.
A 29kW system boiler will cost about £775 (Glow Worm 30kW system boiler)
250 litre unvented cylinder complete with valves is: £1404 inc all valves. Which is £2179.
A Rinnai 32E which saves space as no cylinder, and gives around 25-26 litres/min and does two bathrooms, and NEVER runs out of hot water, and can be fitted outside is £863 and £124 for an external guard and the Glow Worm to heat the CH at £775, is a total of: £1762. £417 cheaper.
The Rinnai will outlast the unvented cylinder and cannot explode causing catastrophic damage. It is best to fit a flow switch on the cold supply to the Rinnai to switch off the Glow Worm CH boiler to keep gas consumption within a U6 domestic meter. Wire it in the stat/programmer circuit in series. When DHW is called (hot tap on) the CH boiler is switched off.
Who the f*ck would be so stupid to spend 1400 quid on a unvented cylinder, which by the way CANNOT explode) when a conventional cylinder at around 100 quid is, in the majority of cases just as good. I say cannot but given a few hours to override all the safety features it might be enough to take off that thick skull of yours, but we digress.
The Japanese are well known for their habit of washing things under running water rather than sticking a plug in it, such a wasteful nation you will not come across (apart from the yanks). A conventional hot water cylinder feeding a power shower will run until your skin wrinkles, if you are having a bath you want to spend ages in it not 5 mins, dump the water down the drain and run a fresh one Although If you are French you'd have a dribbly cold shower lasting
18.5 seconds and come out stinking of garlic and stale sweat.
Oh and by the way £775 + £100 is a lot less than £1762
Also "A Rinnai 32E which saves space as no cylinder"
Yet you add a "Glow Worm to heat the CH" Now this Glow Worm just fits in no space at all then does it, truly remarkable.
Have you got shares in this jap concern you raving tosspot?
"When DHW is called (hot tap on) the CH boiler is switched off."
So unless I fit 800mm of rockwool in my loft I'll freeze when I'm having a bath?
"It is best to fit a flow switch on the cold supply to the Rinnai to switch off the Glow Worm CH boiler to keep gas consumption within a U6 domestic meter"
Nice facility, all approved is it?
To the original poster, go for the system boiler it keeps the plumbing easy plus you loose the header tank in the loft and keep your existing hot water tank. Just forget the ranting's of the dual combi tosspot
- although he has now moved on to a combi and a conventional, who knows given a few million years of evolution he might move on to a single boiler WITH a hot water tank.
You obviously don't know too much about this. Unvented cylinders "can" explode if the safety mechanisms fail. When they go it is a full insurance job. They can take down walls too when they go. Not a nice sight. The price is from discountedheating web site. A Megaflow with valves.
£100, that is cheap and nasty and will not last long. It also requires a cold tank and all that pipe too and then you need power shower pumps, which for a decent one is £250 plus for one shower. Two showers x 2.
It is clear you know nothing of this subject. The UK and Ireland are virtually alone in having the cold tank/cylinder setup. The rest of the world laugh at the Brits. Most here still think Victoria is on the throne.
That they do. And very clean as well.
Their appliances are quite efficient, unlike the Yanks.
And exhausts the cylinder very quickly. You need a large cylinder. In fact that £1400 for the unvented cylinder was 250 litres, it should be over 300 litres if two high pressure showers are being used for any length of time. So, that is even more expense, which is £1,515. Going up!
And the pipework and the cold tank and two power shower pumps. And this £100 cylinder will do two showers with a pump simultaneously? Er no!! So, you are looking at about £400 for a 300 litre minimum two bathroom job. Then a quick recovery coil is even more. Then there is all the zone valves etc. Price is rising here, and all this money for outdated technology that looks like a school boiler house takes up an amazing amount of space and the rest of the world laughs at. And then you have to buy the extremely noisy, vibrating, exopensive power shower pumps too. It's getting worse!
Please read again. Focus a little.
Brainless, you don't know much about this subject do you? Do you work for a cylinder company. they are crapping themselves because high flow combi's and now the Japs are here dragging the nation along kicking screaming. Wait until Tagsaki import here. Condensing 32 litres/minute instant multi-points that consume 190 cu foot an hour. Brilliant. A Tagsaki or Rinnai will outlast an unvented cylinder, even one costing more than ant of the multi-points.
You really are not that bright are you? As the multi-point fills the bath in about 4 to 5 minutes, you will freeze for well, er, er, er, 5 minutes? So, you r 22C house will drop to freezing consditions in "5 minutes". You are having a laugh. You are a one.
..and ther next stupid question..
Yep. All flow switches are CE rated.
The term is cylinder, not tank. Don't give advice on subjects you clearly do not know much about.
BTW, two combi's. Highly cost effective. Two Glow Worms: one 24Cxi's costs £529 and a 30cxi £567 from use less energy, that is only £1096. That is a total of 178 cu foot per hour and a combined 22 litres/min @ 35C temp rise.
One does upstairs CH with a stat/programmer and one does downstairs - two separate zones using less fuel. One does one bathroom, one does the other. Divide and rule and one doesn't influence the other when showers are taken. Combine the outputs for the baths, where high flows are required.
I know of no cost effective way to get:
- two CH zones,
- condensing technology,
- no water storage so no standing losses,
- not running out of hot water at any time
- liberating space in the house
- eliminating a cylinder,
- no tanks in the loft to give off water vapour promoting condensation up there.
- high pressure showers.
Less than £1,100 plus two stat/programmers. How is the cylinder business? Losing ground to superior technology eh?
Nonsense! If you want to know ask, don't make comments on a subject you little about. well you are from Essex.
I did. Please read and understand. I know it is difficult for you.
If you want a two bathroom setup this is highly cost effective, as is two combi's. Beats unvented cylinders and the likes all around in capital cost, running costs, space saving, ect.
Two combi's what? Does this Japanese product own something?
I wouldn't set any particular store as to whether their products are any good or not or even whether they are the largest manufacturer of gas appliances as you claim. I can't be bothered to check either.
However, your track record in this area is quite poor. Only recently, you were claiming that Ryobi was a major Japanese tool product with all that you thought was implied by that, only to discover that they had sold their tools business to a faceless Chinese manufacturing house.
Many places have a cold main that will do 20lpm tops, some even less. With water companies dropping pressures to control leaks this situation is likely to get worse rather than better.
Many people have storage systems that will deliver 30lpm of water at 65 degrees, which mixed with the 20lpm from the cold gives bath fill rates of 50lpm. Twice what your multipoint will do if only it could get the cold water to it at a suitable rate.
So you introduced the unvented cylinder bit just so you could argue with yourself about it?
You should seek help....
But last month you were claiming something else was "by far the best solution".... Which of your deluded personalities are we supposed to believe?
It may be a good solution in some circumstances, but your inability to present balanced reasoning with the limitations as well as the benefits makes you sound like snivelling squirming politician... Still given your political role models I guess that is understandable.
Who the f*ck would be so stupid to spend 1400 quid on a unvented cylinder, which by the way CANNOT explode) when a conventional cylinder at around 100 quid is, in the majority of cases just as good........
Now, brace yourself oh dim one and as Jennifer Aniston the celebrity plumber who once washed her hair said here's the science bit
******* .......I say cannot but given a few hours to override all the safety features it might be enough to take off that thick skull of yours, but we digress.
******
Now then dim one read this:
I DON'T have any financial interest in ANY company associated with central heating
Got it?
I don't have any financial interests in any copper mine either.
Got it?
Now on we go
One more thing I'm still wondering where you will site that "Glow Worm to heat the CH" Does it just fit in no space at all then does it, as David Coleman (ex plumbers mate and celebrity part time sports commentator) once said, truly remarkable.
I know yiou did and it was just as silly then as it is now.
Utter bollocks. I have seen the aftermath of one exploding. Not a pretty sight. It was £1515 in fact llok at discountedheatings web site, Megafklows. And they give good deals.
Youn have been told befire a two bath room low presure cheapo cylinder is NOT £100. go x 5, and then all the valves and cold tank, etc.
It is never as good as a Megalflow or high flow multi-point or combi(s). And the cold tank gets filled with crap, and Legionella can form.
You are an effing liar, or an effing idiot or more likely both.
More hilarity.
Wherever convenient in the house. Duh! Boy are there some thickos on Usenet.
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