Linking Two Unvented Cylinders

[Cardiff Plumber]

Hi Dragoon,

Use a thermal store with a pumped return, if cws supply is an issue use a break tank with a pump and pressurized vessel.

I have a lot of experience with hot water systems. I fitted similar system and all the underfloor heating including the heat extraction system on the telecom's room on top of the tower. This was on this project in Lymm, Manchester, see here: Lymm Water Tower - the art of housebuilding

 

[Dragoon]

Hi Ray.

The size of the incoming blue main is 25mm (I just measured it with a tape measure so may be a millimetre or two out.)

 

[Dragoon]

Hi Best. I think that's a really good idea about the different levels of heating coils.

 

[Dragoon]

Hi AWheating. Thanks for the welcome!

I would really like to say where I am located, however I think I should wait for the replies from the plumbers I have already asked, otherwise they may get a bit offended that I didn't wait for their answers. I may do so at a later stage though.

 

[Dragoon]

Hi Simon G.
Yes as posted earlier, I was thinking along those lines as well. However I don't know if that would be better than what Best suggested about the different coil heights.

 

[Dragoon]

Hi Gray0689

Could you explain what a solar thermal is please.

 

[Dragoon]

Hi Chris Watkins, I’ll do the calcs and get back to you later.

Hi Ray Stafford, the calculation should be quite simple as Y (No of women) =1. However is there a there a variable I should add to the eqn. for the Predictability of Y?

 

[Dragoon]

By the way, I think I realise why I couldn't originally see all the other replies. I didn't realise that there were different pages so was only looking at page one:blush5:

However, I didn't receive any email alerts either so I still don't really know.

 

[Ray Stafford]

Hi Chris Watkins, I’ll do the calcs and get back to you later.

Hi Ray Stafford, the calculation should be quite simple as Y (No of women) =1. However is there a there a variable I should add to the eqn. for the Predictability of Y?

You still need at least 1 wild horse (or reasonable fraction thereof) otherwise the calculation comes out as div by 0.

The predictability of women is such a vanishingly small number that it eludes description even by advanced quantum theoreticians. However, the square root of FA is a good approximation.

 

[SimonG]

Hi Dragoon,

Use a thermal store with a pumped return, if cws supply is an issue use a break tank with a pump and pressurized vessel.

I have a lot of experience with hot water systems. I fitted similar system and all the underfloor heating including the heat extraction system on the telecom's room on top of the tower. This was on this project in Lymm, Manchester, see here: Lymm Water Tower - the art of housebuilding

Definitely not a thermal store, unless you are connecting in multiple fuel sources.

 

[Dragoon]

Hi Cardiff Plumber.
Wow what place that Lymm Water Tower is!!! I wish mine was anywhere near as good! Impressive work!!

I have considered Thermal Stores before and they sound a good idea. The only problem I have with them is that not many plumbers are familiar with them, so if and when things go wrong with them, I wouldn't be able to just phone the first available plumber to sort the problem.

Also in my particular case, wouldn't it again involve heating a large cylinder of water for the occasional use of the bath?

 

[Dragoon]

Lol!! Yeah, wasn't it this Predictability factor that first lead scientists to discover quantum theory?!

 

[Dragoon]

Hi Bogrodder.

There's a temporary curved 25mm copper pipe, shaped like a tap with a lever ball valve as a tap connected to the blue incoming mains. (there is also stopcock on it but I've left that open).

I filled a bucket to 25 litres in 25 seconds. I don't know the pressure as I don't have a gauge.

Bye the way I'm sorry if this is the second time you've received this reply as I'm sure I've already sent it, but I cannot see it on the page. It may have something to do with me using Safari as a browser. Anyway apologies again.

 

[snowhead]

However is there a there a variable I should add to the eqn. for the Predictability of Y?

This is the missing constant ∞

 

[Dragoon]

Hi Snowhead.
Lol! I think that symbol (which I can’t do on my keyboard) = Unpredictability.
So Predictability would be 1/ (that symbol) which would make it pretty close to zero as Ray stated.

It’s a good thing that there aren’t many female plumbers out there or else we’d get deluged with lots admonishing replies from irate members.

In fact I’m going to have to have the Hide button ready when writing in this forum, just incase she walks in! . . . . . . Which will be okay cos she’ll think I’m just looking at naughty stuff again, which is usually considered a lesser crime than any form of direct criticism!

 

[AWheating]

Unvented cylinder and combi boiler used as a system boiler but the hot water from combi supplying the bath and basin in the bathroom.

 

[Ray Stafford]

Unvented cylinder and combi boiler used as a system boiler but the hot water from combi supplying the bath and basin in the bathroom.

If there is no shortage of incoming pressure and flow (and it sounds like there isn't) then this would be an excellent solution, and very cost effective both to install and to run.

 

[Gray0689]

Hi Gray0689

Could you explain what a solar thermal is please.

Solar thermal
Basically tubes or panels on roof (South facing preferably)
That when sun out will heat hot water through a coil at the bottom of your cylinder

And stay away from thermal stores there not good

 

[Ray Stafford]

And stay away from thermal stores there not good

Thermal stores are excellent if you need to integrate multiple heat sources, particularly hard-to-control or unpredictable sources like solid fuel or renewables.

If there is no need to manage such challenging inputs, then its difficult to make the case for a thermal store in a domestic installation.

 

[BLOD]

You could fit an unvented sized for just the shower & hot taps and fit a combi boiler zoned for heating & cylinder but using the hot water side just for the bath.

 

[SimonG]

I wouldnt be keen using a combi to fill such a large bath. It takes about 25 minutes just to fill a standard bath with our gas combi.

 

[Dragoon]

Unvented cylinder and combi boiler used as a system boiler but the hot water from combi supplying the bath and basin in the bathroom.

Hi AWheating

Could you please explain the above system a little more. So would that be the one boiler (a Combi boiler) and one unvented cylinder? If so, could you explain a little more how it would work?

 

[Ray Stafford]

Hi AWheating

Could you please explain the above system a little more. So would that be the one boiler (a Combi boiler) and one unvented cylinder? If so, could you explain a little more how it would work?

Hi Dragoon. I'm not sure whether AW is online, but in case he isn't, this is what he is suggesting.

On the heating side, a combi is just like any other boiler - it has a flow and return which can be used as an S plan (preferred) or Y plan (if you must) to heat a cylinder as well as heating the radiators.

In addition to that, it has the instanteous hot water system, albeit with a limited flow rate, as you have identified.

So if you mate a combi with an unvented cylinder, you can have stored water available for some outlets and instantaneously heated water for others. Exactly how you divide them up is up to you, but normally outlets that use a lot of water, relatively rarely (say a bath) should be fed by stored hot water, whereas outlets that frequently use just a few litres (say kitchen sink) would be better on the instant.

The limiting factor (assuming that the cylinder is unvented) is the capacity of the incoming cold main, but yours sounds like it has plenty of flow at least.

 

[Cardiff Plumber]

Hi Cardiff Plumber.
Wow what place that Lymm Water Tower is!!! I wish mine was anywhere near as good! Impressive work!!

I have considered Thermal Stores before and they sound a good idea. The only problem I have with them is that not many plumbers are familiar with them, so if and when things go wrong with them, I wouldn't be able to just phone the first available plumber to sort the problem.

Also in my particular case, wouldn't it again involve heating a large cylinder of water for the occasional use of the bath?

Well you would have superb insulation with a decent thermal store, so you would be just topping up temp each day. It works very well and have never had any problems in the past.

 

[Dragoon]

Thermal stores are excellent if you need to integrate multiple heat sources, particularly hard-to-control or unpredictable sources like solid fuel or renewables.

If there is no need to manage such challenging inputs, then its difficult to make the case for a thermal store in a domestic installation.

Hi Ray.
Thermal stores sound like a good idea, however I don't have multiple heat sources so it's not really needed in my case. But also I heard that they can be problematic (as with all systems really as they age), and because not many plumbers are familiar with them, that would be my biggest cause of worry with them.