Rads warm all the time - CH not on ???

[andytc]

Hi , I have an odd problem with my Combi boiler and after reading the FAQ I think it may be a valve problem of some sort ?

The boiler is an iSAR made by Ideal , either a HE24 - HE30 or HE35 , prolly a HE24 as it was originally fitted by the local council.

My hot water works fine , the heating works fine , but when the heating is turned off the rads stay warm to the touch all the time. I've just noticed it in the last few days , we've been running it on the timer , coming on twice a day , it goes off at around 10.00pm at night , but 2 hours later the rads are still warm , not hot , just warm. Even the rads on the upper floors are warm , but the boiler shows no demand and the thermostat is set to 0 degrees (off). I've even turned the timer controls to permantly off and they still stay warm.

How are the rads heating up ? especially the upper floor rads with no pump running?

Is our demand for hot water somehow leaking over into the CH part of the system ?

If it is a valve , what valve would it be and is it easy/expensive to replace or rectify ?

thanks in advance ,

 

[plummerman]

It may be the divertor cartridge sticking, so when your running hot water, some of the hot water is passing to heating as well.

Best way to check turn it off let it cool down fully then place a hand on the far left hand pipe about 12 inches down from boiler and then get someone to run a hot tap. if the 22mm pipe your holdin gets hot it's passing and your need to call someone out!

 

[davebgas]

As said your diverter cartridge is passing, but the boiler hot water preheat is keeping the rads warm, in addition to whenever you run a tap. Only way you'll let it cool down properly to do test above isto turn the boiler power off.