Why do yours pull on immersion mate, mine don't as its unplugged can't say I've ever needed to go and plug it in either, we set a hw legionnaire programme for 2 hours once a week at 3am in morning. That's it immersion wise
I think the first thing to say is that I don't think I had an MCS install. I looked in to it yesterday and it was just some random plumber and electrician who fitted my system. My builder/project manager subcontracted them in. I feel a bit like an idiot now, especially since I just found out about the available grant that I won't be getting as well!! The price of not doing your homework I guess. After reading what you wrote, I'm getting alarm bells about the whole installation now.Helllooooooooo
Ok in Scotland for an mcs install you would be designing a system so the unit runs to at least -5, me personally I'd design it to about -7, if customer had any data on actual average land temps of that area we could adjust the curve accordingly, lets start here
What's the unit?
You should have it programmed to run at 20c in day and no lower than 18c at night, its best to run 20c from morning to night with no off times during the day, the units I use come with a back up heater but we ALWAYS disable it as we don't like to use them as running costs can rocket.
Other factors t check is what was the underfloor loop set at ie 120mm centres or 200mm? If 120 great were onto a good start, if 200mm its ok. You want a flow temp from the unit set to about 45-47c max on Ufh. I'd personally if loops were 120 set it so my curve was from 37c in milder weather and 45c for days like now. This lets the weather comp kit control flow temps and I've found that pretty stable in most places. On your floor area your looking at 16kw unit.
If you can provide as much info as needed we can look deeper. I don't come on here much but I'm sure the lads will keep me informed
The £200 a month figure is based on the last 12 months. From all the information I'm getting I can see that I'm just operating it wrong now. I'm interested in the whole 'don't switch it on and off' thing. My Economy 10 tariff gives me 3 periods of Off Peak energy a day. The heating and water is only set to come on during these periods. Are you advising that I should change my tariff to a standard anytime tariff and leave the heating and water to do it's thing for the whole day? I'd certainly much prefer that but wonder if it's a realistic option?On the note about high cost in winter you have to ignore that, you have to take a 12month period and then compare with other months, had a customer who was running a 5 bed house at nearly same cost as oil last winter, issue was it was colder than previous year and cost of elec had gone up he has his 12 month bill in, his oil would cost around £1600 a year, his whole house elec bill inc all his touch screen tvs and lights was £1300, he now understands its a 12 month look at prices and not a 3 month check. I've heard nothing but issues about the grant, so much so that people have taken out and put another in throwing units back at grant. Ashp can be very efficient even more so than natural gas, but they must be set up and sized correctly or they can cost twice as much as oil I've seen some horrendous installs and its getting a bad name because of theses installs.
That sounds exactly like the advice I was fishing for in my last post. I have to admit that it seems counter-intuitive to make it cheaper by having it on for longer periods.have experienced high electric consumption before with people turning the system on and off.
you will need to run the air sorce for a minimum of 18 hours a day but preferable to leave it on 24hrs per day.
reason is purely the following.
when the heat pump first turns on it uses the immersion (direct electric element only 3 or 6kw) to get the flow above 15 degrees.
this is the period when it uses huge amounts of electric.
because you have underfloor it is possible when the system cools down slightly that you could be in a situation where the flow temp doesn't get above 15 for a couple of hours or more.
your electric tariff is also very high. change to single rate but you should get a good deal because of your high usage. don't expect to use less than 12000 kwh per year for heating but could be as high as 20000 kw/h
at present best to have heating on 24/7 and to time the hot water for the cheap periods. also change the underfloor temp to a lower temp from 11pm to 7am ( will reduce demand on air source unit when it is not as efficient due to colder outside temps.)
Thanks again Kev. I'm not sure if the Grant is hot water priority or not but I'll certainly try to find out. As far as putting the heating on all day - I'll try that out when I get home this week.Not sure how the grant works but the bigger manufacturers all use hot water priority, so as soon as the tank has water used it re heats it straight away. You need to make sure your heating is on all day ie 6am to 10pm at 20c, then set 10pm to 6am at 18c MINIMUM, this will keep the fabric of the house stable and you won't get any loss of heat at peak times. It's impossible to say without seeing it and its set up but something is definitely not right.
I can assure you mate, the thought has crossed my mind.Just rip the stoopid thing out and fit an oil boiler.
You're completely right. My main complaint is that my house is cold and I'm still paying a fortune for electricity. I wouldn't mind paying so much and having a lovely warm house. Alternatively, I wouldn't mind it being ridiculously cheap but not up to the standard of oil or gas central heating. What I grudge is the cold house and the cost.I have skimmed through your posts and dont actually see what your main complaint is.
You seem to be sayiong ther house feels cold but even so you dont have your heating on for so many hours.
Its going to be far more expensive for you too if your local electricity is more expensive than the rest of the country.
One would have expected that you would have compared local fuel prices before choosing ASHP? But ASHP usually comes out well in high fuel cost areas.
You say you have rads upstairs. They need to be well sized to give enough heat output with a flow temp of only about 50 C.
It may help you if you can set your water heating to be only during off peak and have your heating on a lower setback temperature at night.
Tony
Domestic Hot Water Boost kit
Whilst it is possible to raise the DHW to 60ºC with an Aerona Air Source Heat Pump, it can be more efficient to set the hot water temperature between 45ºC and 50ºC and utilise Grant’s Domestic Hot Water Booster Kit to take the cylinder up to the desired higher temperature. This unit comprises an enclosure with 20A rated contactor, an override switch and relay, which works with the immersion element fitted in all Grant cylinders.
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