I moved into a flat with the same heater last summer and it took me ages to figure out how it worked. As it happens there are two variations of the SRC 187, one which contains a relay, and one which does not. My particular model does not contain a relay but I know how both variations work. To find out if yours has a relay I believe you will find it behind the cover underneith the heater into which the power cables enter. Switch off both supplies and have a look. A relay should look something like this
http://www.storageheater.co.uk/IMAGES/751001034L.jpg
Once you've found out what type of model you have here's how to work it:
Non-relay model (same as mine)
The off-peak switch supplies power to the storage element. When the switch is left on, power should be automatically supplied to the storage element during the off-peak night-time period. This, however, was not happening with mine, so I changed the switch to a regular plug socket so I could use an electronic plug in timer to control when the power was supplied. The amount of heat stored is controlled by the rightmost control knob on the right hand side of the heater with the word 'stored' underneith it. Turn it clockwise to store more heat overnight. Turning it fully anti-clockwise will not cut off the power completely, some heat will still be stored.
The peak wall switch supplies power to the convector element and should supply power at anytime of the day and night. Turn this wall switch on along with the rocker switch on the left hand side of the heater (neon should light up) to get instant heat from the convector element. The amount of heat given out is controlled by the left most control knob on the right hand side of the heater with the word 'direct' underneith it. Use this with caution though, as using the convector during peak hours is a very expensive way to heat you home.
Relay model
If you have a relay model the peak wall switch supplies power to both the storage and convector elements. The off-peak wall switch energises the relay which directs the current to the storage element during off-peak hours and to the convector element otherwise. So, if you want to store heat overnight keep both wall switches on. Heat will be stored and you have optional use of the convector heater by using the switch on the front of the heater. If you do not want heat to be stored overnight, turn the off-peak wall switch off. That way the relay will never direct any current to the storage element giving you only optional use of the convector.
If you are new to storage heaters (like I was) then the general idea is that they store heat overnight when the electricity is cheaper, and then switch off before the electricity becomes more expensive during the day. They then release the stored heat gradually throughout the day. Personal experience will help you use you heater as economically as possible, as it can depend largly on the size of the space you are wanting to heat and how well insulated that space is. I generally only have the storage side operating between say November and March when I need heat everyday. Otherwise, in spring and autumn I find it cheaper to just operate the convector on the odd cold evening rather that have the storage side on everyday when I don't really need it. On the very coldest winter days you will probably find that the stored heat runs out before the end of the evening and you will need to use the convector as well as the storage side! Also be aware that if the storage element has not been used for some time, like during the summer, it takes about three nights of use before the bricks inside the heater become fully 'charged' and provide maximum heat.
Well I hope that lot helps you. If you still don't understand anything let me know and I will try and clear it up for you
Roger, May 2009
