Hi, We have an old (1970/80's) heating sytem. We have a Concord boiler which feeds the radiators and central heating and an immersion heater that provides the hot water for the taps (bath/sink and kitchen sink). They have always worked independantly, i.e. when we need hot water it would come from the hot water cylinder without the need for the heating to be on. Recently however the hot water cylinder is luke warm at best, and only gives out good hot water when the heating is on as well. What could be the problem? I'm thinking the thermostat maybe dead, but this was replaced about 18 months ago along with a new cylinder.

Craig, March 2011

RE mm:

No we dont have a white meter - everything runs at single rate. The system we have is literally:

Boiler - central heating
Hot water cylinder - bathroom & kitchen hot water supply to taps

The boiler is fine, and we have never needed to use the boiler to heat the hot tap supply before!

Its a conventional boiler, will it be best to get combi/condensing boiler fitted?

Craig, April 2011

i think you guys are talking x purpose here,if i read it right you have a emersion heater,this can be fitted with two or one elements that have their own thermostats,this type of system has norm a boost control,i.e.if you come home after a holiday,you can press the boost control that will turn the emerser on for one or two hours,depending on the switch,the other element is fed through the white meter ,it comes on during the night when the elect,is half price,providing you have left the switch on in cupboard,its very common for the elements to burn out,as is with the thermostats,you can check these with a test meter,turn of the power,remove the round covers of the elements,disconnect the live lead to the thermostat,check across the therm,with meter set on ohm scale,you should get continuity,if you do,check across the heater element,you should get a reading of about 19.5 or 20 ohms,if you get less than this,the element is burned out,repeat for the other element,hope this helps.

mm, March 2011

Hi, no our boiler doesnt have a hot water only setting. It does have a timer, but only buttons are a boost button, all day, twice a day and on. This hasnt happened before and last summer when the boiler was always off the hot water was fine? I was thinking it could be the thermostat on the immersion heater but not sure?

Craig, March 2011

i suspect that the boiler also does the h/water very unusual not to you should have a timer with seperate settings for heating and h/water switch it to h/water only the boiler should come on and heat the water if it doesn't you may have airlock normally the boiler will keep the cylinder hot with the heating on but if you use a lot of h/water the boiler needs to be on h/water only for a short while each day

brian, March 2011