Condenser/immersion heating

ddtwelve12

hi all im new to here and to my new rental home which came with a new condensing boiler and immersion tank heater , ive sussed how to programme my ch/hw timer but i need advice on how to use it proper so it dosnt cost me ££££ to run as im a single dad on low income..at the moment the ch/hw is off due to summer heat..but im still getting hw is the immersion heater on all the time costing ££££ or do i need to turn the hw on with the condensing boiler ????
Any advice would be geatfully accepted

tacpot12

Hi. You need to turn the HW on at the timer. When you set it to come on will depend on when you need to have hot water. You could set it to come on only at 5pm so you have water to wash up dishes from your evening meal and for baths & showers in the evening, but the water won't typically stay hot enough for a shower in the morning. You might need to set it to come on twice; perhaps at 6am and 5pm? 
You will want to set to be on for long enough to heat the tank completely. This should take about 30 minutes, so try this first. Once the heating goes off, check how hot the water is (ideally with a thermometer). Then set the HW to be on for an extra 10 minutes (some programmers only work in 10 minute jumps), then measure the water temperature again the next day. If the water is hotter on the second measurement, it needs the extra 10 minutes. You could try adding a further 10 minutes but it would be unlikely that it would need this unless the cylinder was particularly large or inefficient.

Bear in mind that the water coming into the tank will be colder in the winter and so take longer to heat up, so you might need to add another 10 minutes in the depths of winter. 
Normally your cylinder would have a thermostat and will shut the boiler off when the cylinder is up to temperature, but you don't want to be running the boiler when you don't need to, so try to minimise the time that the HW is on for to 30-40 minutes in the early morning and late afternoon. 

Note that many older programmers only allow ONE time range to be set and then allow you to decide whether you will have heating and/or HW on at this time. This won't allow you to have the HW on for 40 minutes but have the heating on for 2 hours. This is a poor system, but typically in the UK where our heating controls are prehistoric. Some (but still not all) modern controllers allow different times to be set for HW and heating.  

tim_p

For a quick check on your electric consumption, what’s the reading now and what was it when you moved in? Divide this by the number of days for an average daily reading - this should give you some idea of your electricity usage. You should then take daily readings at a similar time and enter them into a spreadsheet and then you’ll be able to monitor the effects of changes to the electricity powered hot water.
you'll probably be better off letting the boiler provide the heat as it’s a heck of a lot cheaper than peak electricity costs.  Unless you’ve got Economy 7 in which case you might find a couple of hours E7 in those off-peak hours will provide enough hot water (obviously depends on your specific usage / needs)

ddtwelve12

Cheers that was very helpful i will check hw timer etc and set it see what happens

Talldave

Consider the immersion heater for emergencies only, if the boiler breaks down.

To put things in perspective, our gas for hot water for the last week cost £1.03, standing charges were £1.21. That's heating a large 300 litre tank

macman

Heating the HW from the immersion is probably going to cost you 2.5 to 3 times more than from the gas boiler.