unvented cylinder and immersion divert

[bladerunnerpv]

I did a google search and a forum search and looked at myenergi website but didn't see an answer anywhere to this specifically, so I presume there are no problems with this,... Probably a daft question, but just to be sure...

I have a combi gas boiler for central heating and hot water, the hot water is stored in an unvented cylinder and there is an immersion heater element near the bottom of the cylinder. Immersion element is connected to a separate electric socket, via a 13A plug from memory. We've never used the elec for water heating, 100% gas.

I have in mind to include an immersion divertor, such as eddi or iBoost in a PV system, are there any issues to be aware of regarding the unvented cylinder?

I've seen a couple of threads suggesting a separate tank for the divertor-heated hot water.

thanks

 

[binky]

Nope, it'll just heat the water like your gas does.

Immersion should not be on a plug, get that changed for a fused spur

 

[ish]

I did a google search and a forum search and looked at myenergi website but didn't see an answer anywhere to this specifically, so I presume there are no problems with this,... Probably a daft question, but just to be sure...

I have a combi gas boiler for central heating and hot water, the hot water is stored in an unvented cylinder and there is an immersion heater element near the bottom of the cylinder. Immersion element is connected to a separate electric socket, via a 13A plug from memory. We've never used the elec for water heating, 100% gas.

I have in mind to include an immersion divertor, such as eddi or iBoost in a PV system, are there any issues to be aware of regarding the unvented cylinder?

I've seen a couple of threads suggesting a separate tank for the divertor-heated hot water.

thanks

I am just going through the same process currently.

We are removing gas altogether (goodbye boiler). I am going with Eddi to send surplus solar to the unvented cylinder which has been recommended by numerous installers and homeowners that have the system.

As @binky said fused spur on an immersion

 

[johnb2713]

I am just going through the same process currently.

We are removing gas altogether (goodbye boiler). I am going with Eddi to send surplus solar to the unvented cylinder which has been recommended by numerous installers and homeowners that have the system.

As @binky said fused spur on an immersion

Eddi is brilliant, it works really well.

 

[bladerunnerpv]

Thanks folks

IIRC I think the socket the immersion plugs into is on the same circuit as the gas boiler and the dolphin shower pump all of which are in the loft, but I'm avoiding going to see what's what up there as I don't fancy being broiled alive at the mo! Heating has a separate rcd at the consumer unit

 

[Murdoch]

I am just going through the same process currently.

We are removing gas altogether (goodbye boiler). I am going with Eddi to send surplus solar to the unvented cylinder which has been recommended by numerous installers and homeowners that have the system.

As @binky said fused spur on an immersion

removing your gas boiler completely? Are you mad?

heating by electricity is about 3 x the cost of gas

and in the winter your costs could be eye watering

 

[ProDave]

I have a combi gas boiler for central heating and hot water, the hot water is stored in an unvented cylinder and there is an immersion heater element near the bottom of the cylinder. Immersion element is connected to a separate electric socket, via a 13A plug from memory. We've never used the elec for water heating, 100% gas.

[pedantic]
If you have a hot water cylinder, then you have a system boiler not a combi boiler.
[/pedantic]

 

[johnb2713]

removing your gas boiler completely? Are you mad?

Probably not

heating by electricity is about 3 x the cost of gas

Not if you use heatpump(s) or a ZEB like Tepeo

and in the winter your costs could be eye watering

Yes it could if wise solutions arent chosen.

 

[ish]

removing your gas boiler completely? Are you mad?

heating by electricity is about 3 x the cost of gas

and in the winter your costs could be eye watering

Solar power and off-peak electricity. The size of the solar PV will generate over the amount of Kw energy needed during most of the winter with the odd pay where we will draw from the grid a little more.

I guess there have to be some idiots in this world that need to go a different route to just gas and try other ways - I don't mind being that person

 

[Geoff1946]

Why remove anything? - unless its at the end of its life of course.
I'm a great believer in system redundancy so that occasional failures aren't as catastrophic.
I'm on gas heating, but have enough electric heaters stored away to cope with boiler or supply failure.

 

[ProDave]

Solar power and off-peak electricity. The size of the solar PV will generate over the amount of Kw energy needed during most of the winter with the odd pay where we will draw from the grid a little more.

If you seriously believe solar PV will provide all your needs in winter, then you have either not modelled the winter generation on PVGIS or, you have installed such a massive amount of PV that it will supply many many times your needs in the summer.

 

[Murdoch]

Probably not


Not if you use heatpump(s) or a ZEB like Tepeo


Yes it could if wise solutions arent chosen.

really don’t buy into this for most of the poorly built and insulated homes in the UK

 

[johnb2713]

really don’t buy into this for most of the poorly built and insulated homes in the UK

The poorly insulated homes make no difference when comparing to gas, if 6000 kWh of heat is required it doesnt matter what the source, the requirement is the same. Heatpumps have an average COP of 3, so the 30p kWh becomes 10p pretty much the same as gas. The Tepeo boiler can charge up on off peak at 9p kWh again near enough the same as gas BUT you gave to take the inefficiency of the gas boiler into account so you lose 20% or thereabouts with that and then add the standing charge for your gas meter. All in all it should cost slightly less than gas IF either of the aforementioned technologies is used, if it's resistive heating then its madness.

 

[bladerunnerpv]

[pedantic]
If you have a hot water cylinder, then you have a system boiler not a combi boiler.
[/pedantic]

Thanks for the clarification ;-)

 

[ish]

If you seriously believe solar PV will provide all your needs in winter, then you have either not modelled the winter generation on PVGIS or, you have installed such a massive amount of PV that it will supply many many times your needs in the summer.

Pvgis used for modelling and summer generation will be many times higher than our current usage but as our lives change this usage will alter so we have factored in for the future.

I know many people that have setup in the same way and removed their boilers, they have experienced no difficulties during winter months with the use of energy efficient products.

I see your point mentioned regarded poorly insulated houses etc and 100% agree that a number of houses will struggle. First thing everyone who can afford to do it is to insulate their properties otherwise they are losing money no matter tech they use be it a boiler, heat pump etc.

 

[ProDave]

I think the big problem with boiler to ASHP swaps in poorly insulated houses is doing half a job. If you expect an ASHP to deliver hot water at 70 degrees to heat your radiators to scalding hot like the boiler used to just to get enough heat into the house, you will be very disappointed and the ASHP will run at a very poor COP if it will even reach the temperature needed.

On the other hand if you do it properly and install under floor heating, or all new over sized radiators that will deliver the heat the house needs at a very much lower water temperature you will get good results from an ASHP.

 

[ish]

I think the big problem with boiler to ASHP swaps in poorly insulated houses is doing half a job. If you expect an ASHP to deliver hot water at 70 degrees to heat your radiators to scalding hot like the boiler used to just to get enough heat into the house, you will be very disappointed and the ASHP will run at a very poor COP if it will even reach the temperature needed.

On the other hand if you do it properly and install under floor heating, or all new over sized radiators that will deliver the heat the house needs at a very much lower water temperature you will get good results from an ASHP.

This is 100% why ASHP have gotten such a bad rep.

There is no one size system fits all properties and everyone should seek best advice. Ask questions and play worst case scenario is always the route I have gone

 

[Murdoch]

Maybe the OP could expand on their original post for clarity …..

 

[binky]

Why remove anything? - unless its at the end of its life of course.
I'm a great believer in system redundancy so that occasional failures aren't as catastrophic.
I'm on gas heating, but have enough electric heaters stored away to cope with boiler or supply failure.

Likewise, and woodburner to boot.

 

[Murdoch]

Yup. Definitely agree.

Gas heating, big hot water tank, immersion via pv and wood burner for extra / occasional heat

Works for us