Megaflo Cylinder for hot water

sebtomato

matelodave said:

Bacman said:

The Megaflow has the main heating element on the top, the bottom is for "boost" if needed. The bottom one itself will not provide hot water due to convection, the top one is the one to use. Get an electrician to install an electric timer so you can set it to come on for a few hours to heat up the boiler rather than being on all the time as the unit uses a lot of power.

The radiator is nothing to do with the Megaflow, it is a stand-alone electric heater. They do dual systems, this is not one of them.

Google "Baxi Megaflow system" and learn about the unit. Normal plumbers in practice do not know how the Megaflow works or how to repair them, although will pretend they do and charge for it. Baxi will refer you to a monthly direct debit with Domestic General, or alternatively if you have a problem phone Baxi directly for them to arrange a qualified plumber to visit.

Also research into "replenish the bubble" if you get water going through the turnish.

If you have general questions, you can message me if you like; we have had a Megaflow for a few years now and had to learn stuff about it (I suggest you do too).

WRONG info. The Megaflow cylinder shown is made by Heatrae Sadia and is an Unvented Direct Cylinder. It does not have a bubble 

Well, you are wrong. This Megaflo has an expansion bubble inside, as per the "Important" label stuck on the side. I have the same, and air needs to be added once in a while, else cylinder starts to make noises (not enough space for hot water to expand) or drip (relief valve).

sebtomato

Bacman said:

The Megaflow has the main heating element on the top, the bottom is for "boost" if needed. 

It's the opposite. Bottom one is heating all the water (as you would expect), while top one is heating only some of the water, for a top-up. And yes, I am sure, I have the same cylinder, and my 30 neighbours too.

sebtomato

Gerry1 said:

Rachel* said:

There is no gas supply, it may be something I look into in the future, but I can’t afford the initial outlay currently.

It would be worth finding out whether gas might be available.  

How often gas is going to become available for a flat???

sebtomato

snowqueen555 said:

Just bumping this old thread. Does anyone have any idea how much this costs to run a day? Looking to buy a flat with this system, but will be basic tariff no economy 7. It keeps the water warm all day, but wondering if there is a way to only have it on a few hours a day and use it like a normal immersion heater with timer.

Thanks

In my case, probably on for about 1.5 hours per night, and the off peak bottom heating element is rated at 3kW. Of course, it depends on the amount of water you use (whether the cyclinder still had warm water or not).

Therefore, hot water is using about 4.5kWh per day/night. Just multiply with your applicable rates.

From the 1st Oct 22, with EDF energy, my off peak/night rate will be 7.85p per kWh, so 4.5kWh would cost about 35p per day.

AliceBanned

sebtomato said:

Rachel* said:

I’ve recently purchased a 2 bedroom flat, which has electric convection heaters and a Megaflo Unvented Direct Cylinder for hot water. 

I’ve been trying to read up about the Megaflo cylinder but just end up confusing myself so was hoping someone can help me. 

1. Is it cheaper to leave this switched on all the time, or just when I want hot water? (I work different shifts each week, anything from 6am to 7pm over Mon - Sun)

2. I noticed there is two switches on the wall, and from my research I believe it is a 2 immersion system? So it is better to leave one on and the other one off unless I want a bath or will be using a lot of hot water in one go? 

I haven’t actually moved into the property yet as I’m still decorating, buying furniture etc. so I have turned it off unless I’m actually at the property and needing hot water. But just want to be prepared for when I move in. 

I have pretty much the same model.

Typically, your flat should have an economy 7 meter, as that cylinder is designed for off-peak use.

During off peak hours, the off peak circuit should be active. This should power the switch going to bottom cable, to heat up water during the night when it's cheap (cheaper rates). The bottom cable leads to the bottom heating element that heats the water...from the bottom.
Off-peak should be 7 hours during the night. Currently 23:30 to 01:30, and then 03:30 to 08:30 with EDF energy in London (other areas may have different hours).

The switch leading to the top cable should only be used for top-ups (only heating up the top of the cylinder, shallow water), when you have used all hot water and needs some more on that day. Don't leave that switch on all the time, only one hour or two should be sufficient, only when you need additional hot water.

If you don't have economy 7, then maybe only switch on for a few hours before you need hot water, or get an electrician to install a timer on the "non-top" up socket, so that you can hot water in the morning when you need it (so for instance switch to be one from 05:00 to 08:00). 

Given the high electricity prices, you don't want those switches to be on all the time. One of my neighbour made that mistake and had a £400 bill...per month.

Mmm I live in an all-electric flat with E7 and NSH. Not sure of the brand of immersion but it has two elements and a timer. I find if I put it on during the later hours of the tariff eg 6am for 1.5 hours, I have enough hot water though not always piping hot as with a nice combo boiler😕. Currently that costs me about £1 a day and I no longer use the boost but I used to if I wanted an evening bath. I have only morning bath or shower (I don’t have an electric shower). 

I am wondering whether I should put it on for any longer than this during off-peak hours as given that the water will be heated does it continue to use more electricity than needed to keep it hot? Unfortunately I can’t access the thermostat so would need to get a plumber in to check it and adjust. It’s ok as it is, not ideal and will cost me closer to £2 a day soon. I presume on days I don’t have a bath it costs a bit less? I went through a phase of turning it off every other day and having cool shower but that’s ridiculous. This energy crisis just makes me frugal though I will be able to afford the bills. I guess it’s mild panic at horrific costs as it’s all electric. I’m sellyup next year anyway and want to go back to GCH (want to move for other reasons). 

Apodemus

sebtomato said:

snowqueen555 said:

Just bumping this old thread. Does anyone have any idea how much this costs to run a day? Looking to buy a flat with this system, but will be basic tariff no economy 7. It keeps the water warm all day, but wondering if there is a way to only have it on a few hours a day and use it like a normal immersion heater with timer.

Thanks

In my case, probably on for about 1.5 hours per night, and the off peak bottom heating element is rated at 3kW. Of course, it depends on the amount of water you use (whether the cyclinder still had warm water or not).

Therefore, hot water is using about 4.5kWh per day/night. Just multiply with your applicable rates.

From the 1st Oct 22, with EDF energy, my off peak/night rate will be 7.85p per kWh, so 4.5kWh would cost about 35p per day.

Maybe someone can check my maths, but my calculation suggests that 4.5kWh would deliver 925 degree/Litres of heating - so if the incoming water was 20C (which its probably not) and the output temp was 45C (and it may be higher), then you are only heating 37 L of new water each day?  This assumes no heat loss in the other 120+ litres of water in the tank.  I don't know what the average household's hot-water use is, but that seems barely enough for one shower?

[Deleted User]

AliceBanned said:

sebtomato said:

Rachel* said:

I’ve recently purchased a 2 bedroom flat, which has electric convection heaters and a Megaflo Unvented Direct Cylinder for hot water. 

I’ve been trying to read up about the Megaflo cylinder but just end up confusing myself so was hoping someone can help me. 

1. Is it cheaper to leave this switched on all the time, or just when I want hot water? (I work different shifts each week, anything from 6am to 7pm over Mon - Sun)

2. I noticed there is two switches on the wall, and from my research I believe it is a 2 immersion system? So it is better to leave one on and the other one off unless I want a bath or will be using a lot of hot water in one go? 

I haven’t actually moved into the property yet as I’m still decorating, buying furniture etc. so I have turned it off unless I’m actually at the property and needing hot water. But just want to be prepared for when I move in. 

I have pretty much the same model.

Typically, your flat should have an economy 7 meter, as that cylinder is designed for off-peak use.

During off peak hours, the off peak circuit should be active. This should power the switch going to bottom cable, to heat up water during the night when it's cheap (cheaper rates). The bottom cable leads to the bottom heating element that heats the water...from the bottom.
Off-peak should be 7 hours during the night. Currently 23:30 to 01:30, and then 03:30 to 08:30 with EDF energy in London (other areas may have different hours).

The switch leading to the top cable should only be used for top-ups (only heating up the top of the cylinder, shallow water), when you have used all hot water and needs some more on that day. Don't leave that switch on all the time, only one hour or two should be sufficient, only when you need additional hot water.

If you don't have economy 7, then maybe only switch on for a few hours before you need hot water, or get an electrician to install a timer on the "non-top" up socket, so that you can hot water in the morning when you need it (so for instance switch to be one from 05:00 to 08:00). 

Given the high electricity prices, you don't want those switches to be on all the time. One of my neighbour made that mistake and had a £400 bill...per month.

Mmm I live in an all-electric flat with E7 and NSH. Not sure of the brand of immersion but it has two elements and a timer. I find if I put it on during the later hours of the tariff eg 6am for 1.5 hours, I have enough hot water though not always piping hot as with a nice combo boiler😕. Currently that costs me about £1 a day and I no longer use the boost but I used to if I wanted an evening bath. I have only morning bath or shower (I don’t have an electric shower). 

I am wondering whether I should put it on for any longer than this during off-peak hours as given that the water will be heated does it continue to use more electricity than needed to keep it hot? Unfortunately I can’t access the thermostat so would need to get a plumber in to check it and adjust. It’s ok as it is, not ideal and will cost me closer to £2 a day soon. I presume on days I don’t have a bath it costs a bit less? I went through a phase of turning it off every other day and having cool shower but that’s ridiculous. This energy crisis just makes me frugal though I will be able to afford the bills. I guess it’s mild panic at horrific costs as it’s all electric. I’m sellyup next year anyway and want to go back to GCH (want to move for other reasons). 

The photo above shows a well-lagged unvented cylinder. I have a 250L unvented cylinder that we heat throughout the day using diverted solar electricity. The daily heating requirement averages 3kWh/day during the Winter season. Adjusting the immersion heater thermostat is a simple and safe operation if you turn the power off. Some cylinders have visible adjusters on the face of the immersion heater: others have a cover which is screwed on. Behind the cover, you will see something like this:


For an unvented cylinder, the temperature should not be set below 55C.

Don't be seduced into thinking that gas re-heating of a cylinder will always be cheaper. Re-heating my cylinder by gas uses an average of 7kWh/day: why?

1.  The boiler goes to its maximum flow temperature so it is not that efficient (ie; no condensing so gas efficiency will be c.80% of electricity)).

2. The boiler water flow through the cylinder initially removes heat from the cylinder.

3. The pipes between the boiler and the cylinder will also be emitting heat. (clearly, this contributes to heating the home)

k_man

Apodemus said:

sebtomato said:

snowqueen555 said:

Just bumping this old thread. Does anyone have any idea how much this costs to run a day? Looking to buy a flat with this system, but will be basic tariff no economy 7. It keeps the water warm all day, but wondering if there is a way to only have it on a few hours a day and use it like a normal immersion heater with timer.

Thanks

In my case, probably on for about 1.5 hours per night, and the off peak bottom heating element is rated at 3kW. Of course, it depends on the amount of water you use (whether the cyclinder still had warm water or not).

Therefore, hot water is using about 4.5kWh per day/night. Just multiply with your applicable rates.

From the 1st Oct 22, with EDF energy, my off peak/night rate will be 7.85p per kWh, so 4.5kWh would cost about 35p per day.

Maybe someone can check my maths, but my calculation suggests that 4.5kWh would deliver 925 degree/Litres of heating - so if the incoming water was 20C (which its probably not) and the output temp was 45C (and it may be higher), then you are only heating 37 L of new water each day?  This assumes no heat loss in the other 120+ litres of water in the tank.  I don't know what the average household's hot-water use is, but that seems barely enough for one shower?

I think you are out by a factor of about 4.
4.5kWh will heat approx 150l of water from 20C to 45C

sebtomato

Apodemus said:

sebtomato said:

snowqueen555 said:

Just bumping this old thread. Does anyone have any idea how much this costs to run a day? Looking to buy a flat with this system, but will be basic tariff no economy 7. It keeps the water warm all day, but wondering if there is a way to only have it on a few hours a day and use it like a normal immersion heater with timer.

Thanks

In my case, probably on for about 1.5 hours per night, and the off peak bottom heating element is rated at 3kW. Of course, it depends on the amount of water you use (whether the cyclinder still had warm water or not).

Therefore, hot water is using about 4.5kWh per day/night. Just multiply with your applicable rates.

From the 1st Oct 22, with EDF energy, my off peak/night rate will be 7.85p per kWh, so 4.5kWh would cost about 35p per day.

Maybe someone can check my maths, but my calculation suggests that 4.5kWh would deliver 925 degree/Litres of heating - so if the incoming water was 20C (which its probably not) and the output temp was 45C (and it may be higher), then you are only heating 37 L of new water each day?  This assumes no heat loss in the other 120+ litres of water in the tank.  I don't know what the average household's hot-water use is, but that seems barely enough for one shower?

I don't know about your math, but my energy consumption is correct, as per my smart meter (and actually, probably below 4.5kWh most days).

There is very little heat loss in a megaflo, due to internal insulation. My model is the 210 litres model, with two 3kWh heating elements (off peak and top up/boost).

I hardly use boost, unless I want to take a bath in the evening, and may run out of hot water. In that case, I use boost for 1 hour.

sebtomato

AliceBanned said:

sebtomato said:

Rachel* said:

I’ve recently purchased a 2 bedroom flat, which has electric convection heaters and a Megaflo Unvented Direct Cylinder for hot water. 

I’ve been trying to read up about the Megaflo cylinder but just end up confusing myself so was hoping someone can help me. 

1. Is it cheaper to leave this switched on all the time, or just when I want hot water? (I work different shifts each week, anything from 6am to 7pm over Mon - Sun)

2. I noticed there is two switches on the wall, and from my research I believe it is a 2 immersion system? So it is better to leave one on and the other one off unless I want a bath or will be using a lot of hot water in one go? 

I haven’t actually moved into the property yet as I’m still decorating, buying furniture etc. so I have turned it off unless I’m actually at the property and needing hot water. But just want to be prepared for when I move in. 

I have pretty much the same model.

Typically, your flat should have an economy 7 meter, as that cylinder is designed for off-peak use.

During off peak hours, the off peak circuit should be active. This should power the switch going to bottom cable, to heat up water during the night when it's cheap (cheaper rates). The bottom cable leads to the bottom heating element that heats the water...from the bottom.
Off-peak should be 7 hours during the night. Currently 23:30 to 01:30, and then 03:30 to 08:30 with EDF energy in London (other areas may have different hours).

The switch leading to the top cable should only be used for top-ups (only heating up the top of the cylinder, shallow water), when you have used all hot water and needs some more on that day. Don't leave that switch on all the time, only one hour or two should be sufficient, only when you need additional hot water.

If you don't have economy 7, then maybe only switch on for a few hours before you need hot water, or get an electrician to install a timer on the "non-top" up socket, so that you can hot water in the morning when you need it (so for instance switch to be one from 05:00 to 08:00). 

Given the high electricity prices, you don't want those switches to be on all the time. One of my neighbour made that mistake and had a £400 bill...per month.

Mmm I live in an all-electric flat with E7 and NSH. Not sure of the brand of immersion but it has two elements and a timer. I find if I put it on during the later hours of the tariff eg 6am for 1.5 hours, I have enough hot water though not always piping hot as with a nice combo boiler😕. Currently that costs me about £1 a day and I no longer use the boost but I used to if I wanted an evening bath. I have only morning bath or shower (I don’t have an electric shower). 

I am wondering whether I should put it on for any longer than this during off-peak hours as given that the water will be heated does it continue to use more electricity than needed to keep it hot? Unfortunately I can’t access the thermostat so would need to get a plumber in to check it and adjust. It’s ok as it is, not ideal and will cost me closer to £2 a day soon. I presume on days I don’t have a bath it costs a bit less? I went through a phase of turning it off every other day and having cool shower but that’s ridiculous. This energy crisis just makes me frugal though I will be able to afford the bills. I guess it’s mild panic at horrific costs as it’s all electric. I’m sellyup next year anyway and want to go back to GCH (want to move for other reasons). 

If you want to be frugal with utility cost, you need to avoid taking bath, and cut showering time.

Your immersion tank should have thermostats, so even if you extend the timer to switch on for 3 hours instead of 1.5 hours, it doesn't mean you will use twice as much electricity. Once the water has reached the desired temperature (e.g. 55C), heating will stop.