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

[Mr.B]

To be honest I've always thought unvented cylinders went hand in hand with System Boilers not gravity systems. The installer who was round here recently made that suggestion and he's a pretty switched on bloke. But, like I say, it's always been the de facto suggestion - or al least I thought it was.

Over the years I've read plenty of Tony's posts.


And that's all I shall say.

 

[MNW67]

Tony you cannot be serious.
What you are suggesting, can be done but good chance gravity circulation my not be possible with indirect coil in UV cylinder.

This scenario highlighted in a recent thread. Gravity circulation in UV cylinder almost non existent

I think there's been a bit of confusion in terminology. I think it's a fully pumped system, both radiators and cylinder. When OP said gravity, I think he meant F+E open vent.

 

[Mr.B]

Correct

 

[Agile]

When I say gravity fed I mean supplied by gravity from a header tank. Not pressurised and sealed Danny.

Not that the cylinder heating coil is not pumped!

 

[Mr.B]

The boiler (an Ideal Vogue 32kw Max combi) has been in five months now.

There was an initial difficulty in getting the Halo RF wall stat to talk properly to the receiver (interface) that was mounted in the boiler in the garage (separated by a nine inch wall.) ... but the interface has now been repositioned inside the house and connected via a cable and, to cut a long story short, it works.

But to return to the dedicated cold feed that I provided for the boiler, the interested reader might recall there was some conversation about whether there would be any benefit to be had in giving the boiler its own supply run straight back to where the 25mm MDPE cold water supply enters the house, under the kitchen sink.

It comprises 22mm for the majority and reduces to 15mm for the last metre or so as it enters the boiler and has a 22mm pressure reducing valve in the run (set at 3bar).

Some here told me it was a good idea to give the boiler this supply that has nothing else coming off it - and others told me I had wasted my time.

Some advised AGAINST fitting a combi - full stop (I'm looking at you, here, Bernie but there were others). And I admit I was totally anti - combi for most of my adult life.

But I have one now and can only speak as I find and say it's excellent. Obviously the heating side of it can'tbe faulted ... it's 32kw and I have 15 rads - but the hot water is fine too. There's only a short run from boiler to shower and bathroom and it comes through in a very acceptable time. Using a toilet flush has no discernible effect and ditto using other cold taps. If you turn on the hot tap on the washbasin next to the shower then the hot supply to the shower is definitely impaired, I would say that you could just about manage two showers at the same time but at substantially reduced flow. Remember it's December and the water in to the house is much colder than in summer so that might change things a bit but I accept it won't do multiple hot outlets at the same time and still maintain good levels of performance.

Whether the cold supply running back to the MDPE entry into the house has made a scrap of difference I will never know but using the shower is a different experience now and it seems that the winter cold water temperature has made little, if any difference to the hot water from the boiler to a single showqer .... it's more than enough - in fact I've fitted flow restrictors to the showers to prevent it coming out with excess gusto.

Anyway, I'll stop there - this was intended as a follow up with the benefit of five months actual first hand use. Bernie.

 

[Mr.B]

Looking back, above, I see a mini shock arrestor was recommended. The installer fitted one without me asking for it.

Mention was made in the thread of the possibility of the radiator pipework leaking under pressure. I was obviously worrying unnecessarily coz it didn't.

Others said I should have fitted an unvented cylinder. Agile said keep my old, gravity, Classic FF250 fo feed it. The fact is I didn't want one. I now have a really useful airing cupboard with no cylinder in it. It does have a small rad and an electric 40 watt tubular heater on a timer in there though. It now houses all the stuff my Mrs wanted to put in it and she's happy. It's got shelving and towel rails and the interface for the Halo. It's got power and lighting and accommodates the gas suppy from the loft en route to the garage. I didn't want an unvented cylinder in there. I don't have to get an unvented cylinder serviced annually either.

The installer did favour putting the Vogue combi in the airing cupboard but in the garage it's out of the way, completely silent and takes up no space in the cupboard.

Re. the Vogue, the installer was experienced in fitting all sorts and was very happy to see a Vogue in there. He made a first class job of fitting it, I'm relieved and pleased The Ideal engineer who visited to look at the Halo was a gem.... 26 years with Ideal and knew his stuff. I'm happy to know he's there if ultimately needed for warranty work - he's the local area engineer.