Immersion heater question?

alastairq

Hi.....Am on Economy 7, [storage heaters, etc]...with hot water supplied via tank, with single immersion element....plus a timer...and in rented house.

Recently, the hot water tank was replaced following demise of old heater element....tank/heater had been previously 'bodged'....unable to effect repair...[I agreed with plumber on inspection]

New tank now fitted, and I tested the system thoroughly.

However, I am disappointed in its performance compared to the old system......in respect of....the quantity of hot water delivered in one go [bath-filling].

In other words, the new tank [after proper heating time allowed] provides just over half the quantity of hot water the old one did, before it ran cold.

Since the cylinders are/were roughly similar in size..[the plumber is pretty sure the element is a 27 inch one]....I have worked out that the difference is down to the temperature setting on the thermostat....[as compared to the old item]


As it is a single element cylinder..I am aware that the bottom levels will always remain cold...so I presume the old thermostat had a higher upper temperature limit, thus providing 'more' hot water?

I have done a layman's search of suppliers, to try and find a thermostat which offers a high[er] max temp......but these days they all seem to go no higher than 70 degrees!

Does anyone have ideas or suggestions for increasing the amount of hot water available from this cylinder? [without stopping to re-heat...or filling kettles?}...are there any thermostats out there that allow higher temps?


One luxury I allow myself is a deep hot soak every night...eases the aching bones, for one!

jalexa

alastairq wrote: »

Hi.....Am on Economy 7, [storage heaters, etc]...with hot water supplied via tank, with single immersion element....plus a timer...and in rented house.

...unable to effect repair...[I agreed with plumber on inspection]

...New tank now fitted, and I tested the system thoroughly...

This should be a plumbers "test question" but before that, if it is a rented house, why and what did you agree?

On the "temperature issue" for safety reasons, including landlord safety reasons, I hope you cannot find a thermostat with a higher setting. You will struggle to find one which goes higher than 65deg.

There is probably more than one issue here, but the first issue is the size of the cylinder. Who chose that and why? Is the size limited by space? Any cylinder, not just Economy 7, needs to be big enough for the projected demand, specifically bath filling.

Normally an "Economy 7" cylinder would have 2 elements, a lower main element connected (only) to overnight "cheap-rate" and a upper "top-up" element connected to the timer. Someone has completely mis-specified the cylinder replacement. In fact *probably* the cylinder has space for a lower element. Maybe it is even fitted but the "plumber" is not an electrician.

If you only have one element I do not understand the role of the timer. How long "*exactly* is "proper heating time" and at what time?

Cardew

jalexa wrote: »

If you only have one element I do not understand the role of the timer. How long "*exactly* is "proper heating time" and at what time?

I believe you are talking about an Economy 7 system where the immersion heater(and storage heaters where fitted) are only supplied during the 7 hours of off-peak electricity.

Not all houses with Economy 7 have that arrangement. On mine for example all electricity for the house is switched to Off-peak for 7 hours and is on 'daytime' electricity for the other 17 hours.

Thus to use the immersion heater on off-peak electricity I need(and indeed have) a timer that I can set to come on for the required length of time during the 7 hours off-peak period. The timer(obviously) wired between the Immersion on/off switch and the heater.

jalexa

Cardew wrote: »

I believe you are talking about an Economy 7 system where the immersion heater(and storage heaters where fitted) are only supplied during the 7 hours of off-peak electricity.

OK, perhaps I should have said "I do understand the role of the timer..."

What I was really trying to do was to tease out whether the OP understood the role of the timer and "proper heating time"...

grahamc2003

Not sure if you realise the thermostat usually can be adjusted to give the required water temperature. The plumber may have left it set to the mninimum, and if he has, you can simply get a screwdriver and set it to a higher temperature. 75 seems much too high to me - there's a real danger of scalding and you'd lose much more heat from the tank. I have mine set to 55 iirc, and 60 should be plenty hot enough for anyone. A bath temp is usually around 40, so you still need to add plenty of cold water when you run the bath.

Notyetavet

Forget about the vanity and luxury of a daily bath and negotiate with your landlord for a cost effective instant electric shower. They retail out at about £60+ and will repay for itself within a couple of months and that is a twice daily use. (Time served plumber).

alastairq

sorry, commitments meant I couldn't get back to reply soon enough....

The cylinder was the nearest 'like-for-like' unit available...maybe metrication means a wee bit smaller? The location is a little restricted for space....I didn't think to suggest a bigger unit at the time......maybe I should have done....I am considered by the agent as an good tenant..ie I change my own light bulbs.

The original, and current, cylinders are for single heaters only...I used to have a twin immersion cylinder at my last house.....In this house, existing 'dead' plumbing suggests there was once a back boiler range in the kitchen...which has been removed....this would have fed the tank, with a stand-by immersion.....might explain the lack of a twin immersion tank originally?

the timer is a digital control box, able to pre-set the times the immersion heater switches on and off, plus various types of boost.

Being on economy 7 means that the complete electrical system in the house goes onto off-peak rates for 7 hours during the 24 hour period, between the times set on the off-peak meter....as noted by Cardew above?

Therefore the hot water boost from cold is done during off-peak hours...as is the washing machine, tumble drier, and anything else I have which guzzles leccy.......[they all have timers...useful little things, really]

As a working , sometimes single parent, this is quite an acceptable life style.....I ain't at home during the day!

I also have an electric shower....


but as I said, I prefer a bath, and a deep one at that...[age, and an outside, sometimes dirty job means my bones suffer....no pen-pusher, me! Sorry, nowt to do with vanity...more to do with effective easing of pain.]...and the original heater did just that...certainly for the three years I have been here...

Yup, the hot water was almost scalding [boil-in-the bag stuff?]....and was tempered by additional cold water.....which suited me, as quantity of nice hot bath water was the important issue.....

yes, the plumber did set the thermostat to a 55 degree setting....I have already set it to max at an indicated 70 degrees.... definitely not as hot as it used to be!

The trouble is...although the stat is set for 70 degrees...that isn't the water temp by the time it has run into a bath! Even though the tank is effectively along-side!

It really is all about how much, or little hot water emerges before it runs cold....in my case, currently around one third of a bath.....compared to the old tank that gave two thirds full before running cold..... obviously its immersion heated the water further down into the bottom of the cylinder.

A bigger cylinder is the obvious answer, I know...if only I had gas!!...

So..are there any thermostats out there with a higher temp range?

moneysaver78_2

ok PLEASE can you lot help me? im expecting my first bambino soon & the bad weather is fast approaching so i need to sort my heating out ASAP. i have been reading so much on the net & on here that i am so confused & literally have square eyes....
my house has ceiling heating (heat mats) which are breaking & yes i hear you say heat rises so whats the point? i have no gas in the road so am all electric. the ceiling heating is on all day which is expensive (it cannot go on E7) but my emersion is on E7 although this seems pointless because it is a 3bed house and all 3 adults work 8am-5pm . the water that was heated on E7 over night is wasted as we all shower in the evening & so ive had to put a timer on the emersion which heats up at peak time :O(
i have been reading about water filled rads/ air source pumps/ storage heaters/electric boilers/wet systems..... allsorts... and its driving me literally insane i just want some sound straight forward advice please on a system thats not going to cost me the earth to install and is as economical as possible to run.....i was thinking of electric boiler & water filled rads plugged into E10? but as i say the more i read the more i get confused...i need to decide and install fast PLEASE HELP ( Cardrew you seem harsh but knowledgable! :O)
many thanks in advance

Richie-from-the-Boro

Cylinder type - direct - no timed off peak immersion heater - E7
Elements - 27 inch - 1
27 inch is the element the quantity is from say 90 to 330 litres
Stat set to - 70 degrees
Various types of boost - wrong control - that's E10
Where is the heating element top - bottom middle ?

Is it an E7 part L compliant [ totally different insulation / lagging quality ] cylinder ? .. .. no its not

An E7 has two [ top & bottom ] heater bosses the bit you screw the heater into stats into. The usual 30mm foam insulation that most non E7 standard cylinders are sprayed with has poor insulating qualities and can give off poisonous gasses in the event of a fire and will naturally decompose in the greater scheme of things. Flexilag or equivalent used in Part & cylinders outperforms the polyurethane foam by up to 40%.

What in size [ litres ] is your cylinder ? .. and .. Is [ because you are heating your cylinder overnight it is important to not to loose the stored heat by the mornings ] it lagged to E7 standards

Swipe

It sounds to me like your element is too short. Get them to swap it for a longer one.

greyteam1959

Swipe wrote: »

It sounds to me like your element is too short. Get them to swap it for a longer one.

I would agree.....why does everybody have to get so flippin' complicated........