Potterton Profile 50E not starting for DHW

[psarinuk]

Hello,

My Potterton Profile 50E is currently setup for DHW only twice a day through the timer (summer setup).

For some reason it did not fire this morning when the timer came ON.

When I turned ON CH through timer, the boiler started and fired straight away (I could hear the 3 port valve move). So turned the CH OFF but the stone cold boiler would not fire at all for DHW only.

The only way I could get DHW working was to start the timer for CH (for ~3 seconds), let the boiler begin to make pressure to fire and then turn CH OFF while the demand for DHW was still ON from timer. Then the boiler worked normal for DHW.

Last year it had a new 3 port Tower valve and has been running good since then. I am thinking it could be some faulty thermostat but will let the experts guide.

Thanks.

 

[undertrained]

I wouldn’t suspect the thermostat if it carries on after ch has been on, sounds more like your 3 port valve again. Maybe invest in a good quality one or check your system for sludge.

 

[psarinuk]

Thanks Chris.

I remember using CH cleaner, then draining and adding the inhibitor last year. The water quality in the F&E tank is also a lot better (just checked). I will try to repeat this process before winter (unless the DHW issue becomes persistent).

I replaced my age old Tower 3 port valve with a new exactly similar Tower valve, so was hoping quality would not be an issue.

I still have the old one. Would you know if these 3 port valves can be cleaned?

 

[ianmcd]

sounds like a lazy synchron motor in the Tower valve, personally I only fit Honeywell

 

[psarinuk]

Hi Ian,

Technically I am unable to get your point. The CH demand has been OFF for months from the timer. The 3 port valve has been engaged to DHW cylinder since.

So unless there is a demand for CH, why would the motor even need to move between CH and DHW?

Is there something else involved here that I am missing?

 

[psarinuk]

A quick update: The (non) issue was the thermostat on the hot water cylinder. For some reason it was set to ~40 degrees and due to heat wave, the demand for DHW would not come on I presume, so the boiler never fired.

I moved it to 60 degrees and the boiler has been firing up fine since.