Towel Rail connected to hot water tank?! And Mixergy Tank any good?

[ndoubt]

Friends! Please lend me your ears..
Is it 'normal' for towel rails to be heated directly from the hot water tank?

Just moved into a place with an indirect unvented system, Bosch+Megaflo, and been having some real issues with efficiency/cost. I put a timer on the megaflo to limit waste there (i actually got an evohome hot water kit but am yet to find someone who can install it!), but have just realised that the towel rails have been plumbed in to be fed from the tank rather than the central heating system.. Im guessing that is just horrendously inefficient as the hot water im saving for showers etc is just getting pumped out and cooled by towel rails? Or am i missing something here?

As a secondary point, im thinking about dusting the old megaflo in favour of a Mixergy tank given the fact it seems much more efficient in the current climate, and much more user friendly with the app and usage stats etc.. anyone have any experience?

Thanks for help/advice!

 

[JohnD]

Friends! Please lend me your ears..
Is it 'normal' for towel rails to be heated directly from the hot water tank?

It is not done very often, but it is quite correct to plumb the bathroom towel rail or radiator so it is warmed by the boiler while the cylinder is heated (it is not heated by the cylinder)

It is done by taking a small spur or bleed from the boiler pipes heating the cylinder.

It has the advantage that it will typically be warmed during and after a bath or shower, which is ideal.

The towel rail should be fitted with a TRV so it does not come on in hot weather.

It is not wasteful or inefficient.

 

[JohnD]

I put a timer on the megaflo to limit waste there

Do you mean your boiler does not have a programmer? That's unusual.

Your cylinder will have a thermostat so it stops demanding heat from the boiler once it is hot. The insulation is very good, so (unless you use it) it will stay hot for days.

For efficiency, heat the cylinder morning and evening, starting 20 minutes before normal bathtime. Ordinary sink basin and handwashing will not use up all the hot water.

 

[JohnD]

been having some real issues with efficiency/cost.

How many cubic metres of gas do you use per day when the boiler is set to Hot Water Only? (No heating).

Is it more than one?

 

[ndoubt]

Thanks for the reply re the towel rail - i just assumed it was being taken from the hot water tank ... I had a plumber recommend i should put a timer on the pump that services the towel rails alongside some other recommendations which then surely wouldnt make sense?

Im not sure what you mean by programmer, but the boiler is a Greenstar 40CDi Classic. We dont need the amount of water that the current set up allows for (CL300HE megaflo tank for 2 adults, 2 toddlers).. so i assumed that the Megaflo would just be continually topping up hot water when we didnt really need it, hence i installed a timer.. at the mom it comes on for 15-20mins at 5.45 and does 1 shower, then 30mins at 7.15 which can do another and a wash up or 2 etc... then finally at 4.30 for 45mins which covers a bath and just about one other shower. In all honesty it doesnt feel very efficient at all.
I dont have the stats for cubic metres usage per day (i had meter fitted yday and waiting for a 'normal' days usage to find out whats what)

Really appreciate the help John

 

[JohnD]

What size is your cylinder? If it's 300 litres, heat it fully, once a day. An hour will be plenty. It is more economical to heat it once or twice, completely, than multiple short times.

Modern cylinders are not inefficient.

 

[JohnD]

A boiler programmer typically controls the on/off times for heating and hot water. They are often integral to the boiler but you can get separate ones. Except on very old systems, the times for HW and CH need not be the same.

Combis do not need an HW timer.

Examples

Greenstar Comfort digital programmer | Worcester Bosch

Professional information for our Greenstar Comfort control is a twin channel programmer that plugs directly into the boiler allowing you to accurately control the temperature in your home.

www.worcester-bosch.co.uk

Programmers | Central Heating Controls | Screwfix.com

Extensive range of Central Heating Programmers available at Screwfix helping you to save money on energy cost and have a cosy home. Choose from top brands.

www.screwfix.com

 

[ndoubt]

it is 300l - i'll give it a whirl for an hour and see if it holds. pretty sure it wont though given what i said above about how ive set up the timer and what i get out of it.

in terms of boiler programmer - i had an evohome zoning kit installed, which is fine for the heating (as i say i got th ehot water kit too but cant find someone willing/able to install - even from the recommended installer list)

 

[JohnD]

I suppose there is a faint chance the towel rail might have been plumbed to draw hot water from the cylinder, but this would be very strange, and it would quickly go rusty.

 

[ndoubt]

What's the best way to establish if its drawing water from the tank or just taking it from the boiler as it heats the tank..?

 

[JohnD]

Watch to see when it gets hot. I expect it to be during your one-hour cylinder heating cycle (though it will stop earlier once the cylinder is hot, and restart if you have a bath or shower during that time)

Note the gas meter readings before and after. They will be more meaningful if CH is off.

 

[Tigercubrider]

It would be very unlikely to be connected to the cylinder supply. When you had a bath, draining the tank. it would go cold?
If you have an immersion, use that as a test. The towel rail might warm slightly but only by conduction through the pipes.

I grew up with the boiler water that heats the cylinder also heating the bathroom towel rail and was amazed that others didn't?
Spring/Autumn it's nice to have warm towels but no heating.

 

[ndoubt]

Yes following the bath it would go cold, but that could be due to the timer switching off too? Assume i would be able to trace the pipework to see if it was running from the boiler or the tank?

 

[JohnD]

A bath holds around 100 litres of water, some of it cold. Less if you are portly.

You say you have a 300litre cylinder.

If it was fully heated as I recommend, a bath would not drain it of hot.

However, if the timer was off, the towel rail would go cold.

I have a similar arragement (I think it is the best method) and the bathroom radiator comes on after I start to run the bath, as the cylinder is reheated. My cylinder is smaller than yours.

My plumbing is slightly more complicated (better) so the bathroom is heated during CH and also during HW cycles. Less common.

 

[ndoubt]

John - you were right - towel rails are spurred off the the hot water before it hits the CH/HW valves so I guess i have same set up as you.

To your question on how much cubic m of gas I’m using in a day - looks like it’s about 3?! 30kwh. That’s high right?

One thing I have just noticed, my megaflo looks like it needs air gap recharging - can that affect efficiency?

Thanks again