Intermitent hot water supply to taps

Hi, The hot water supply to taps has become intermitent (bath & sinks). When taps are opened hot water is supplied initially then gradually goes cold and then fluctuates between hot and cold. I've checked the sensor readings and found the following:
T1 Started at 66 and gradually reduced until both boiler and pump lights came on (T1 on = 63 & T1 off = 70), I checked the boiler and it was definately fired up.
T2 (PHE) read 85 and remained at 85 throughout.
T3 (DHW) Started at H53 and reduced down to 35 then fluctuated between 43 and 28.
I also noticed the DHW pump started and stopped throughout, green bar on and off and I checked the pump and it was definately running and then stopping in line with the light.

My feeling is that the T2 sensor is faulty as its reading high and doesnt change, can anyone advise if this sounds correct?

Thanks

Nick

Hi Nick,

If you move the PHE sensor around you will find the reading changes, install a new PHE sensor and it should be fine.

Kind regards

Gary

MK Group Limited

Thanks Gary

I've got a sensor on order, can you tell me if it necessary to drain the system down to change the PHE sensor?

Thanks Nick

Hi Nick,

If you are confident and the system is cold you can do a cut and snatch, if you are not confident then I would suggest you drain the system.

Kind regards

Gary
MK Group Limited

Hi NIck

Gary is correct in the PHE sensor diagnosis, however, I wouldn't advise you changed the PHE sensor without draining the system.
Water is held in the store at approx 73deg C and this can cause a very nasty burn. It generally only takes around 5 - 10 mins to drain the unit enough to replace the PHE sensor (if you use the drain point next to the sensor), but 3 - 4 weeks to recover from a nasty burn!

As I said previously only cut and snatch if the system is cold!