Fitting an immersion heater to bottom of Hot water cylinder

[mpooley]

Has anyone ever retro-fitted an extra immersion heater at bottom of a indirect hot water cylinder?
Can it be done?
what fittings would I need?

any advice would be appreciated.

thanks

Mike

 

[Burnerman]

If there's no blanked off boss in place, I'd forget about that one.....can you fit a longer element to the existing place?
John

 

[Jackrae]

You ca get 2.25" Essex immersion heater bosses but as previously said, it's the hard way to do the job.

 

[denso13]

4 and 6 bolt heaters still available but never fitted one on an indirect cylinder as the coil will probably get in the way.

 

[mpooley]

Thanks folks
my tank is 25 years old and we live in a hard water area so maybe I should buy a new one but I haven't found an indirect cylinder with fittings for two immersions yet.

I hadn't thought about a longer immersion element as I have never heard of one!
any ideas where I might get one.

thanks again

Mike

 

[stardanny]

You can buy 36" immersion heater, but it depend on size of cylinder and whether indirect coil get in the way.

You can order a indirect cylinder with 2 immersion boss.

Why do you want 2 immersion heaters?

Daniel.

 

[mpooley]

You can buy 36" immersion heater, but it depend on size of cylinder and whether indirect coil get in the way.

You can order a indirect cylinder with 2 immersion boss.

Why do you want 2 immersion heaters?

Daniel.

thanks that sounds as though it might be expensive though?

what I am trying to do is use excess electricity from my PV to heat as much water as possible during the day so that it will last the whole day till the next morning and only top up the top of the tank with imported electricity if necessary.

thanks

 

[CombustionGuy]

Get one made Pts can get them made an they don't cost that much draw a simple diagram( how tall and wide and where you want coil and immersions ) and they can get a price for one to be made for you normally only takes a couple of days

 

[Richardthe3rd]

Sort of begs the questions;
a) Why are you not dumping PV onto the national grid? Then getting cheap tariff leccy to heat your immersion heater?
b) Why don't you fit a twin element immersion heater?
c) Why can't you wire up a Relay to switch over your single element immersion heater?
d) Why have you fitted PV panels when the panel's output will diminish ever the next 5-8 years. Thermal solar would have been much better choice.

Sorry for all the questions.

 

[mpooley]

Sort of begs the questions;
a) Why are you not dumping PV onto the national grid? Then getting cheap tariff leccy to heat your immersion heater?
b) Why don't you fit a twin element immersion heater?
c) Why can't you wire up a Relay to switch over your single element immersion heater?
d) Why have you fitted PV panels when the panel's output will diminish ever the next 5-8 years. Thermal solar would have been much better choice.

Sorry for all the questions.

No problem I didn't go into detail as I didnt want to bore anyone

a. I don't get any extra payment for dumping to the national grid so it pays me to use as much of my own production as possible. I don't have economy 7 as I don't think it would pay me. we cook electric etc and most of the year the 7 hours after the PV stops producing and the economy 7 comes in is when we use most of our leccy.

b. I had not heard of them till today but I found out just before reading your post so I am looking in to it now.

c. dont really understand what you mean here. I do have a solid state relay that switches it on/off run by a computer program I wrote.I can switch it on/off when my PV starts/stops producing but that means we wake up to cold water in the morning and sometime run out late evening.
Hence the reason to have one immersion to heat the water on free electric and another smaller one to just top up the tank.

D. I didn't get the PV just for the hot water! it is a very good investment.
I have had the panels for 4 years and I get much more then the estimated output from them and I doubt they will diminish as soon as you think.

 

[Richardthe3rd]

Sort of begs the questions;
a) Why are you not dumping PV onto the national grid? Then getting cheap tariff leccy to heat your immersion heater?
b) Why don't you fit a twin element immersion heater?
c) Why can't you wire up a Relay to switch over your single element immersion heater?
d) Why have you fitted PV panels when the panel's output will diminish ever the next 5-8 years. Thermal solar would have been much better choice.

Sorry for all the questions.

No problem I didn't go into detail as I didnt want to bore anyone

a. I don't get any extra payment for dumping to the national grid so it pays me to use as much of my own production as possible. I don't have economy 7 as I don't think it would pay me. we cook electric etc and most of the year the 7 hours after the PV stops producing and the economy 7 comes in is when we use most of our leccy.

b. I had not heard of them till today but I found out just before reading your post so I am looking in to it now.

c. dont really understand what you mean here. I do have a solid state relay that switches it on/off run by a computer program I wrote.I can switch it on/off when my PV starts/stops producing but that means we wake up to cold water in the morning and sometime run out late evening.
Hence the reason to have one immersion to heat the water on free electric and another smaller one to just top up the tank.

D. I didn't get the PV just for the hot water! it is a very good investment.
I have had the panels for 4 years and I get much more then the estimated output from them and I doubt they will diminish as soon as you think.

There's already reports of the performance of some PV panels dropping significantly, with little or no recourse to the good old people republic of China.

I don't understand why you can't use your existing set-up to pull on your relay during daylight hours?? Of course with any top entry immersion heater you'll never heat a full cylinder of hot water & if it's an indirect one, the chances are it's too small to be heated with daylight power, to provide enough hot water to cover your needs.

How much power does your PV produce in a normal day & do you dump it onto batteries?

 

[mpooley]

Obviously day to day varies enormously but on a yearly basis I produce about 6000kwh and export about 4500kwh of that.

I like the idea of batteries but have briefly looked into it in the past and the problems are too many and the cost of that idea ballooned out of all proportion.

I already do use my relay to run the immersion during daylight But it still means I either have cold water in the morning or I have to pay to heat my tank before I get up.
I can make an open source designed device that only dumps to immersion when I have surplus, this uses a triac to control the power deleivered to the element to exactly match my export in any given second.

but there is no getting around that my tank won't stay hot overnight (even though it's well insulated)
so I am thinking that I will only heat the top of my tank with the paid for leccy then the other element to heat the whole tank will turn itself on when the PV starts exporting.

although to be honest as I have been thinking about this more and more this week I do wonder How much money I will save. The cost of the project is mounting up especially if I need a new tank.

I might do it just for the fun of it though as I do like to tinker with electronic and computer programming But I am seriously doubting the payback time of commercial devices like the ImmerSun.