Do I need to change my water cylinder?

[Spinball]

Hello folks, I am hoping to get some advice, please, on whether or not to change my hot water cylinder.
I recently moved house and the heating control is an old wall thermostat and rotary dial.

I want to investigate converting it to a smart system (that I can control with an app), maybe with weather compensation, and definitely appropriate for the addition of an eddi controller on the immersion heater to heat the hot water with excess solar energy.

I currently have a fairly new vented thermal store connected to (an also fairly new) Ideal logic heat 18H boiler which I am told is suitable for priority hot water and also weather compensation.
But the volume of water within the thermal store is central heating water, the secondary pump is then activated by the room stat which then draws off hot water to supply the radiators.
I understand that if I were to fit weather compensation as the system is configured now, the thermal store would be supplied with a lower temperature of water, which will fail to sufficiently heat cold water coil supplying the taps.

It was suggested to me that I need to change the hot water cylinder to an unvented cylinder with hot water priority.
However, I am wondering whether the current configuration might be better for use with the eddi to heat the house with spare solar power.

I know virtually nothing about plumbing and hot water systems. Any advice you can give would be greatly appreciated.
Thanks

 

[Chuck]

I don't think you want weather compensation if your boiler heats a thermal store in the manner you describe.

The eddi needs a cost-benefit calculation tailored to your house, lifestyle and plans. Keep in mind that in the summer when you will have surplus electricity you will also need to use less energy for heating. Whether you have, or plan to have, an electric car comes in to the equation and the tariffs that are on offer from your energy supplier. Home battery storage seems to be coming into fashion just to add another layer of complexity.

I'd want a fairly compelling reason to change from a recently installed vented hot water cylinder to an unvented one because they aren't cheap. Also, if someone fitted a vented cylinder it may have been because the water supply to the house doesn't meet the spec needed for unvented.

I'm not a fan of "smart" internet connected systems. They are quite pricey, the novelty wears off, I don't trust 'internet of things' devices to be secure and I suspect their lifetime will be closer to a few years than a couple of decades.

What I would do is replace the dumb thermostat and mechanic time-switch controls (assuming I've understood you correctly) with a modern programmer-thermostat, something like the Honeywell TR4. This change alone will, in my experience, will reduce the fuel needed to keep the house comfortable by about 5%.

Replacing the thermostat can be a DIY job if you are confident with electrical work but for anything more complicated I'd suggest getting a local heating engineer to review your current system and offer some recommendations. Someone on site can often spot things that a text description misses.

 

[ShaunCorbs]

You sure it’s a thermal store ?

 

[Spinball]

I don't think you want weather compensation if your boiler heats a thermal store in the manner you describe.

The eddi needs a cost-benefit calculation tailored to your house, lifestyle and plans. Keep in mind that in the summer when you will have surplus electricity you will also need to use less energy for heating. Whether you have, or plan to have, an electric car comes in to the equation and the tariffs that are on offer from your energy supplier. Home battery storage seems to be coming into fashion just to add another layer of complexity.

I'd want a fairly compelling reason to change from a recently installed vented hot water cylinder to an unvented one because they aren't cheap. Also, if someone fitted a vented cylinder it may have been because the water supply to the house doesn't meet the spec needed for unvented.

I'm not a fan of "smart" internet connected systems. They are quite pricey, the novelty wears off, I don't trust 'internet of things' devices to be secure and I suspect their lifetime will be closer to a few years than a couple of decades.

What I would do is replace the dumb thermostat and mechanic time-switch controls (assuming I've understood you correctly) with a modern programmer-thermostat, something like the Honeywell TR4. This change alone will, in my experience, will reduce the fuel needed to keep the house comfortable by about 5%.

Replacing the thermostat can be a DIY job if you are confident with electrical work but for anything more complicated I'd suggest getting a local heating engineer to review your current system and offer some recommendations. Someone on site can often spot things that a text description misses.

Thanks for the reply.
I didn't think it would be relevant to mention it, but I already have an EV and am having PV and a battery installed ASAP. The Zappi is waiting here for 3-phase to be installed at the end of the month.
The goal is to save on energy bills as much as possible. I thought weather compensation might be a route to go.
It's a 90's 4 bedroom house with 2 occupants working from home and we take showers every day.
I just had the loft insulation increased with thermaquilt over the ceiling joists, adding to the existing rockwool.

Yes, a basic controller on the wall under the boiler for setting on/off times. I'll research the Honeywell. I'm not going to touch electrics myself.
I've had a Hive previously and found it useful for controlling the temperature via my phone.
But I've learned that they are not the best compared to others.
I was even thinking about having individual radiator thermostats.

 

[Spinball]

You sure it’s a thermal store ?

Erm. It's a hot water tank. Isn't that a thermal store?

 

[king of pipes]

Pictures would help please ??

 

[ShaunCorbs]

Erm. It's a hot water tank. Isn't that a thermal store?

There’s different types

 

[Spinball]

Thank you.
This is in the airing cupboard on the landing. It's always very hot in there.

 

[king of pipes]

Yes I would definitely get it changed the money you are investing in the house in renewables it is not suitable there are many options talk to your installer. Kop

 

[Spinball]

Yes I would definitely get it changed the money you are investing in the house in renewables it is not suitable there are many options talk to your installer. Kop

Thank you. So I can clear the expense with the other half, could you say why, please?

 

[king of pipes]

A thermal store needs to be heated to 65° to 70°c 365 days of the year in summer to provide Hot water and for Heating and Hot water in the winter months this is not fuel efficient, gas and electric prices have now more than doubled and the system you have is wasting lots of energy , with summers getting hotter why would you want to have that heat emitting from the cylinder into your home it must be so uncomfortable ?
A modern unvented cylinder is the way you should be going , choose one to match the system you are having installed it may be better to talk this through with your installer. Kop

 

[Chuck]

This is in the airing cupboard on the landing. It's always very hot in there.

It will be, the hot pipes should have been insulated by the installers.

 

[Spinball]

It will be, the hot pipes should have been insulated by the installers.

Yes, I was planning on having a plumber do it, but if a new tank is needed, then I’ll be killing two birds.

 

[Chuck]

Yes, I was planning on having a plumber do it, but if a new tank is needed, then I’ll be killing two birds.

Your tank looks relatively new so whether it needs to be replaced depends on how the losses and running costs of the existing system compare with the losses and running costs of whatever hypothetical replacement system you have in mind. This needs to be calculated not guessed. The fact that the losses are occurring inside the thermal envelope of your house is also relevant to the calculation.

 

[Timmy D]

Whatever you do, ensure you check the mains flow rate/pressure before going unvented.

 

[Spinball]

Whatever you do, ensure you check the mains flow rate/pressure before going unvented.

Thanks. It’s pretty powerful. At least 3 bar, I would say. It feels as powerful as in my last house which was measured at around 4 bar when we had an unvented system put in.
Put it this way, the shower heads will fly off the holders if we turn them up full blast.