Pump not turning off

[Cenci]

This has been driving me mad lately

The heating pump seems to be running all the time for hot water

When on central heating only it cuts in and out fine(presume the signal coming from room stat is working )

But when in hw mode the boiler seems to cut out ok but the pump always runs.

Could it be the cylinder stat? I turned it down to 50 and the pump stopped but I have a drayton hts3 and I think it cuts out there anyway doesn't it?

The water from the taps seems alot hotter than the 55-60 setting

 

[Cenci]

Wanted to Add that I can turn the pump off fine if I turn it off at the programmer. It's just if we have the programmer on continuous heat the pump always runs (hw only)

 

[seco services]

If you leave the pump running does the boiler fire up again ?
Sounds like the stats still calling for heat to cylinder but the boiler had shut down by the boiler stat.

 

[Cenci]

The boiler turns on and off at random intervals through the day so I think its working correctly,

Shall I change the hts3 stat? Is this a common likely fault to keep the pump running? It works fine in ch mode only

As I mentioned I can get the pump to turn off my turning the stat to 50 but I think that's off mode anyway in that stat, I think it's not getting to its satisfied temp

 

[seco services]

If you say the stat is set at 60c but water seems alot hot, maybe check temp at tap then poss stat is not shutting down at 60c.

If the pumps running i would say the boiler will more likely keep running it's just shut down on boiler stat then will cycle again.

Quite a common fault.

Turn the cylinder stat back up slow what temp does it click at ?

 

[Cenci]

I can turn it off (pump) at 50 then clicks back on when I go back above 50

I tried leaving it on about 52 (just above minimum) and waiting for an hour and the pump never stopped , but the boiler cut in and out

There's no other clicks through the range of the stat

 

[seco services]

It clicks on at say 52c but your waters def alot hotter you say.

Then sounds like the stats had it.

 

[Cenci]

Yeah I'll change it tom
Was gonna get a cheap one off eBay but I'm impatient so will pay the £15 at screwfix
Appreciate the help

Also, slightly off topic but I have Really old Drayton room thermostat, just a rotary knob. Are they easily interchangeable with a newer LCD type (love the heatmiser prt) or does it need more connections

Thanks

 

[seco services]

honeywell cm907 is a nice stat.

 

[Cenci]

Just to let you know, cylinder stat replaced and problem fixed thanks