Electric Boiler help!

waingels

Hello- I've recently moved into a  house which has an electric boiler & Water tank system. Having only previously lived in houses with gas boilers I'm amazed.....actually shocked, by the cost of running electric boilers for central heating. 
I have a Heatrae Sadia Amptec C600 boiler which the manual says has a 6kwh output......I therefore assume that it uses 6kwh of energy when in operation. So then why does the smart meter show 8.5kwh usage when the heating is on (everything else switched off). It's approx 15 years old (same as house) could it be that the element needs fixing ?
Would appreciate suggestions / help as I'm already starting to save to pay for the coming winters heating bills!

matelodave

If its got a 6kw element then it will take six kw and will use 6kwh in one hour. What else is turned on, I guess its got a pump, what about your fridge, freezer, TV, SKY box, router and any other of the myriad of stuff that you dont realise is working. Is there an immersion heater in your hot water tank that's switched on.

Unfortunately heating your place with a flow boiler is actually the most expensive way you could choose apart from burning real £5 notes in a grate. There is really no way to reduce the consumption except by turning it down or off. IMHO they should be illegal. Even using an oil filled radiator in one room at a time can work out less expensive to run than a flow boiler.

The only way to reduce the cost of heating is to either  get on the cheapest tariff you can find or find somewhere else to live. 

lohr500

Perhaps a better test of what it is actually using might be to switch it off and then see what the smart meter says about your consumption. Just so you can be sure what the background consumption is. It will only use 6kW when heating, so 6kWh means it is heating for a full hour. I am not sure what smart meters show in terms of usage over what period of time as I don't have one.
You could also check the actual meter reading, rather than any smart display. Switch the heating off for a couple of hours so it cools down. During that period record the start and end meter readings without switching on or off any other appliances. Then switch it on and capture the meter reading every 15 minutes for say 2 hours, again without switching any other appliances on or off. That would give you a good comparison of how many units the boiler is using. There will probably be a circulation pump associated with the boiler which will use a little electricity. Something like 0.030 to 0.050 kW per hour if running full time.

My gut feel is that if it was actually using 8.5kW when running, then that's 40% more than it is rated at and it would be tripping a fuse breaker. Can you do take some more readings and let us know whet you find? 

waingels

Thanks for the reply, i've done what you've suggested a few times previously ie- switch heating off and then on to see the difference and the deviation is 8.5kwh. 
The smart meter can show 'current usage' so i'm constantly running around the house turning switches off!  Also the reading correlates with the physical electric meter (recently checked as switched energy provider).
On your point about the circulation pump, would you know why there's two installed and is it necessary to be on as the power switch is currently off along with the immersion ?

molerat

Or is it a C900 boiler ?

lohr500

Its hard to tell what the two pumps are doing from the photo, and I'm no expert in the 1st place!! molerat does have a point. Is it definitely the C600 model?
The other thing I am thinking is perhaps the immersion heater kicks in at the same time as the boiler, so the boiler does the central heating and the immersion does the hot water. Again I'm no expert, but if you are going to use electricity to heat both the central heating and hot water, would it make sense to heat the hot water in a cylinder directly by an immersion. Although you mention the power switch is off to the immersion, is there a separate immersion heater switch near to the tank? If so, try switching that off and see if the consumption drops. Most immersions are 3kw or 6kw. If it was a 3kw immersion, then knock that off your 8.8kw, and you get very close to the rated output for the boiler. Or, if you are competent enough, check the wiring on the immersion to see if it is live when the boiler is switched on. ONLY DO THIS IF YOU ARE CONFIDENT ENOUGH TO DO IT SAFELY!!
As far as I can tell from the boiler installation manual, there should be one pipe in and one out. The flow is from the top. Can you follow that pipe around and see where it goes. If you can, you might be able to figure out why there are two pumps. How many levels in the house? Do you have any zone type controls with different thermostats in different areas. Sometimes different zones are circulated by different pumps. 

waingels

molerat said:

Or is it a C900 boiler ?

Funny you say that , there's a C900 model parallel to the C600, however there's no lights lit on the display , and all the wiring from the 2nd fuse box goes directly to the C600. The only reason why I can think it's there, connected to all the plumbing pipework was the original owners had both C600 & C900 operating in tandem , which must have been eye wateringly expensive!

lohr500

Could the covers have got swapped over? Are the units the same size?

waingels

lohr500 said:

Could the covers have got swapped over? Are the units the same size?

No idea if that's the case , I only moved in last week . The units are the same size.  

lohr500

If you feel competent enough to isolate the power and remove the covers, you could check the data plates inside the housings.

waingels

lohr500 said:

Its hard to tell what the two pumps are doing from the photo, and I'm no expert in the 1st place!! molerat does have a point. Is it definitely the C600 model?
The other thing I am thinking is perhaps the immersion heater kicks in at the same time as the boiler, so the boiler does the central heating and the immersion does the hot water. Again I'm no expert, but if you are going to use electricity to heat both the central heating and hot water, would it make sense to heat the hot water in a cylinder directly by an immersion. Although you mention the power switch is off to the immersion, is there a separate immersion heater switch near to the tank? If so, try switching that off and see if the consumption drops. Most immersions are 3kw or 6kw. If it was a 3kw immersion, then knock that off your 8.8kw, and you get very close to the rated output for the boiler. Or, if you are competent enough, check the wiring on the immersion to see if it is live when the boiler is switched on. ONLY DO THIS IF YOU ARE CONFIDENT ENOUGH TO DO IT SAFELY!!
As far as I can tell from the boiler installation manual, there should be one pipe in and one out. The flow is from the top. Can you follow that pipe around and see where it goes. If you can, you might be able to figure out why there are two pumps. How many levels in the house? Do you have any zone type controls with different thermostats in different areas. Sometimes different zones are circulated by different pumps. 

The fuse board switch to the immersion is also off , The water from boiler goes to the red pump , which looks to direct the outflow to both the radiator system and the water tank. 
The yellow pump appears to receive water flow from the water tank , then splits off in 2 separate pipes going under the floor ( into the unknown !)
The pump switch is also off , I haven't turned it on as the pipes connected to yellow pump looks corroded, so want the engineer arriving next week to confirm its operational ( it makes standard  noise when switched on , but I haven't left it operating in fear of a leak as system is on top floor ). The pump being off is most likely the reason why ground floor radiators take a while to heat up.
The house is 3 stories , no zonal thermostat, just a nest control. 
The maze of Pipeworks makes me really miss my previous gas boiler in my Victorian flat!