DIY Doctor UK DIY Forums

Hi

The water and heating come on via the wireless termostat but for the past few days we've noticed that the heating comes on at random intervals. most rads get warm (not hot) but one upstairs gets hot. Then CH goes off by itself!

The thermostat doesn't show the CH being on but when we turn the temp down it usually goes off. Until earlier today. I noticed all rads getting hot. As usual the termo wasn't showing the CH on and when trying to turn the temp down it wouldn't switch off. So reset the boiler and still got the same problem

Any ideas? i don;t think its the frost thermo as its not been that cold for a few weeks

It could be a fault with the frost stat though.


htg

infact, i don't think it would be the frost stat onm the boiler. The programmer has one to kick in at 5 degrees but it is switched off.

The boilers built in frost stat is a seperate function on the control. There are 4 controls:

reset,
CH/HW,
standby (only starts boiler once temp drops below 5 degrees)
H Water only

I've just been out to the boiler and noticed a slight leak and the pressure is really low! not to zero though. I've put the pressure upto 1.5 and ther is a slight leak - is this related?????

If it's coming on with no demand than it's likely to be a faulty frost stat, change the CH sensor and see if it stops coming on (CH sensor is the frost protection)

The leak is unlikely to be the cause unless it's getting onto electrics - but obviously needs repairing.


htg

I have the same problem with my Glowworm Xtramax HE...
The Central Heathing randomly comes on....The rads get luke warm, but not hot. I sometime get an F6 error which indicates it's a Flow Thermistor error... I have had the flow thermistor replaced last Saturday, but still getting the problem.... I called the plumber again today...waiting for a call back...

I too have a wireless thermostat, but cannot think whether that is sending some sort of signal to the bolier to switch on. The termostat display shows everything is OFF.... I have also switched thermostat off completely, but that does not seem to make a difference.

The bolier will also come on even when I have turned the CH dial to off...Which indicates its some sort of override issue???

I would appreciate if you share any info you find out, and I will do the same...