Which Boiler/System To Go For. Advice and Help Needed

[posativek]

Pretty much yes.

The boiler will switch modes when the shower is on and ignore heating and the cylinder for the duration.

In practice you would never notice this.

Limiting the flow to sink and basins will save you water too.

All I have to do no, is see whether I get enough pressure from the mains.
Plus I get the right combi. I see you recommended one. I will look it up.

 

[posativek]

A bath shower mixer complicates things as my idea relies on the shower being separate.

Other than that, you had the jist.... now you're moving away again.

The flow restrictors are there purely to save water consumption and minimise the risk of a surprise when under the shower.

The combi is JUST doing the shower (not bath) and a select one or two sinks and basins (maybe).


Again, this won't work unless you have a separate shower valve and bath tap.

Oh rats.with

Typical I suppose. It seems nothing to do DIY is designed to work in your favour.

So the alternative is to either put in a separate shower, or find a plumbing solution to the tap issue?
or change the system idea to something like a mega flo, or back to a pump?

 

[bell824]

my proposal is this will be at least a 5 pager!!

dan is as i know the master of brainwork design and radical as it may seem dan has another great proposal

dan your wife and kid better get home soon your thinking to much

 

[Lusi83]

Sorry - just marking my place and don't know if there is a better way ... I was looking for something else- but my dad (not internet savvy) has the same shower problem - now talking about a cylinder with an expansion vessel...but interesting to see what other solutions there could be...

 

[Dan Robinson]

dan your wife and kid better get home soon your thinking to much

Is that what they're calling it now? .

That reminds me - need to cut in a new stat position for my OTTS - Hot water is a little pants. Now where did I put that angle grinder?



Lusi, your dad is thinking of an unvented cylinder like the OP.

There are several installation considerations, not least the size of the incoming mains water supply and your local pressure and flow rate from the mains.

The cost of upgrading that if needed may make your eye's water.

The two of your should have a search of the forum for phrases like Dynamic pressure ... this has been covered an awful lot.

 

[posativek]

Well after spending the night resting on all my new found information, I went down to my local 'Covers' to chat with the guy in the bathroom department.

He suggested for ease and cost/ short term solution that I put in a pump.

I still cant help feeling that for an extra £500 its worth getting the megaflo.

I dont think im gonna go for the combi because I dont like the idea of taps taking pressure and temperature away from the other.

On the other hand, to have a bit of both as Dan suggested wouldnt be a bad thing either. The only draw back I can see though is, I will have to go back into a new bathroom to fit an independent thermostatically controlled shower, and all the tiling issues that will cause, plus extra plumbing and cost of shower so were looking at about £600 for that on top of the combi and installation.

It seems that maybe just throwing in a Megaflo is the in between choice.
In theory I get to keep water strong throughout the house with even hot water. I get to keep my boiler, and most of the original plumbing so installation should be easy.

Later I can always add in a closed system boiler (if thats correct) and have that just heat the water and central heating.

That seems like a good way to go IMO and appart form the pump, the most bang for my buck.

If however the Megaflo needs annual inspections at £100 a pop and rising, then it might not be on the cards.

In which case, I will go for a pump.

It would be nice to move the boiler out of the kitchen, so when I upgrade that (happening soon) then I can have more cupboards and a nicer looking Kitchen.

Question?

What is the difference between the closed system boiler, and the conventional boiler?

Can I run my current system on a closed system boiler, and pump for shower without any major plumbing or expense.?

If I can, what would be the advantage? How much more effective are closed system boilers and what one would I need.

Ive have been recommended the HSE 30 SB (I forgot the company but they are Dutch) Seems like a good bit of kit that wont go worng.

Regards

and thanks for all replies.

 

[posativek]

A system boiler works the same as the open vented you have got except it has an expansion vessel and that removes the need for a feed and expansion tank and also the pump is in the boiler, which means it has a very efficient means of removing air from the system, no rad bleeding means no sludge. i am about to go on a one day course with intergas to have a better look at there boilers, I know they do a 30kw it is called intergas combi compact HRE 30SB and comes with the option of an external expansion vessel which i prefer for maintenance purposes. They are very reliable with very few moving parts and their combi version doesn't use a secondary heat exchanger and divertor valve which means less to go wrong, they are Danish manufacture and have been going for 10 years I believe, might be longer, produced about 1.5 million boilers. I also plan to put one in my house. next year.

OK sorry I have puled this from earlier.

Ok im confused by this message a bit. Were talking in the beginning about
a system boiler, and then you mention a combi? were did we jump to that?

I dont really want a combi, but do like the sound of the closed system. Please could you explain a bit more. Can I use a closed system with a pump.

I have decided to stay away from compression boilers because they seem like so much work to go wrong. Fans in the flu and freezing.

 

[Dan Robinson]

A sealed system is referring to the heating side - nothing to do with tap water pressure/flow.

A megalfow may well require a significant outlay in upgrading your water main as well. Unless you pump into it as well as the cold water - or go down an accumulator route.

 

[SimonH2]

What is the difference between the closed system boiler, and the conventional boiler?

Traditionally, as I believe you have, the primary system (ie the water that goes round the rads and the heating coil in the hot water cylinder) is "open vented". Up in the loft is a small feed and expansion tank - as the water in the system warms up, it expands, and the level in your F&E tank will rise a little. As the system cools and the water contracts, the level drops a little. There's a ballcock for filling the system and maintaining the level - but normally this will stay closed pretty well all the time. There is a small pipe from the bottom of this F&E tank to the system and the water flows through this as required.
In addition, there is a vent pipe which comes from a high point of the system, and any trapped air can vent up through this pipe - it's normally turned over so that if any water goes up it and it "pumps over" (shouldn't happen in a properly designed system) then it purs back into the F&E tank.

These days it's more common to have an unvented primary. There's no F&E tank, instead the system is filled from the cold mains via a filling loop (which includes more than one non-return valve). To allow for water expansion there is an expansion vessel which has a flexible diaphragm to separate the water from a pocket of compressed air.

Both systems have pros and cons, and I'm sure that just mentioning that will start a debate on why and open vented system isn't appropriate for any installation


Now, back to your situation.
There is another option I suggest you at least consider - and don't be put off because some people here will tell you that they cannot ever be a sensible option. That is a thermal store (TS).
What you could do is replace your current hot water cylinder with a thermal store, heated by your current boiler. The simplest installation would mean leaving everything as is except you'd disconnect the cold water storage cistern in the attic, and connect the mains cold feed directly to the cold inlet on the TS. You'd also connect anything else (possibly the cold tap on the bath) that runs from the cold water cistern to the mains. Now all your hot water and cold water taps etc run from mains pressure - but unlike an unvented hot water tank (eg the Megaflow) you do not have a pressurised tank, so the issues around that do not occur.
For a little more plumbing work, you also alter the central heating so it runs from the store (and so only indirectly from the boiler) with it's own pump. Because the flow rate through the heating doesn't affect the flow rate through the boiler, the pump can now be a modulating type and give you a very quiet central heating system.

So, how does this miracle work ?
You have a tank of hot water - this can be the same water that goes round the radiators and boiler (there are several options). Winding it's way up inside the tank is a tube through which your hot tap water flows - and it absorbs heat through the walls of the tube so it comes out hot at the top.

A different variant, usually called a heat bank, has an external plate heat exchanger (and another pump, and flow switch). These have their own pros and cons.


Cost wise, a TS will probably set you back a bit more than an unvented cylinder, but the advantages may be worth it - that's something only you could decide.
EDIT: One disadvantage both a TS and heat bank share with a combi and unvented cylinder is that they rely on you having an adequate dynamic flow and pressure from your cold mains.
But you can have an immersion heater and so have a backup if your boiler breaks down - this may even be able to contribute to heating if you plumb things up that way.


So, over to the usual guys, let the TS bashing commence

 

[Dan Robinson]

So, over to the usual guys, let the TS bashing commence

If only you knew .