Worcester Heatslave Pil Boiler

[Harri1863]

Over last days l have problems with boiler diverting to hot water. Its under a service contract and 3 engineers visits over last 10 days. Problem persists despite numerous parts being changed including diverter valve and switch, pcb etc. Works intermitrently but then switches to just hot water which gets really hot. Can anyone help please .. another visit due tomorrow

 

[oilhead]

Don't know what Pil is, but I'd be checking the DHW thermostat and ensuring the slave tank is fully bled before chucking any more money at parts.

 

[Harri1863]

HI thanks for reply. Its under service contract with WB so not costing me! Just very frustrated that it will not work. What is Pil? Do you think its the thermostat? Why would you bleed the slave tank? I know nothing about boilers but am trying to second guess the engineer when he calls again tomorrow

 

[oilhead]

Just realised that 'p' is next to 'o' on the keyboard, so assume it is oil, as I thought. You bleed the slave tank so that the thermostat pocket is in water. If it is dry, the DHW thermostat never gets hot, so constant demand for hot water, same as if DHW thermostat has failed. But if WB cannot sort it out, what chance us mere mortals?

 

[Burnerman]

Change the P to an O?
One more call for a thermostat issue.....I had some occasional boiling on one of these and the 3 bleed points on the top of the boiler all had air present.
John

 

[Harri1863]

Thanks for the replies. It appears you both think its a thermostat problem? Hopefully next engineer will know what to do to get it working again. Hot water is fine .. but at this time of year l need the heating. If anyone else could shed some light l would be grateful

 

[Terrywookfit]

Faulty h/w flow switch maybe ??

 

[Harri1863]

Hi they did the flow switch and then the valve.
So went to bed last night and turned hot water off. At this point heating had not worked since 10am. Left heating on timed to come on at 6am. Woke this morning heating is working. I have turned it to low and constant and as of yet have not turned on hot water or used hot water! It appears then that the heating works from a cold start! Any ideas ??

 

[oilhead]

DHW stat or air in the top of the slave tank.

 

[snb]

i would go with,
1, air in slave tank
2, flow switch sticking
3, diverter head/valve sticking

 

[Harri1863]

Thank you for all your suggestions. Engineer due tomorrow so l shall second guess him and hopefully we can solve the problem. Heating on constant and still working!

 

[Harri1863]

Hi all .. WB came out and changed every physical part again. Two weeks later intermittent divert again to water. Boiler appears to start from cold in the mornings with no problem. Was left on constant during the day and turned itself off during the afternoon again diverting to water. Has happened several times. Water is switched off btw on control pad. Have put up with this but will have to call WB again ... any ideas??

 

[oilhead]

Do you have the built in programmer? If so, turn both heating an d hot water off, switch off all power to the boiler then turn it back on and select heating. If it works correctly, suggest to the WB engineer that you may have a faulty programmer. Have seen this fault several times.

 

[Harri1863]

They have replaced programmer at the start of the month along with stats, diverter switch and valve .. pump etc. In some cases replaced twice. Its a heat slave 12/14. We have had diverter switch problems over the years but this is usually an easy fix. Am trying your fix as we speak . Boiler has been off all day since it switched to hw at 11 am. Should have turned on at 5pm to ch but went to hw. So turned it off again. Gets hot inside really quickly. Pressure is above 1 so l am not sure what is going on.

Yaay it worked . Well l think its kicked in and appears to be a sustained burn rather than a minute to heat water

10 mins later .. rads warm .. which is a novelty these days!

However l know this panel.has been replaced twice since end of December .. probs started Chrustmas Eve!!!

But thanks so much at least we have some heat.

Why do you think it starts from cold an then when on cobstant reverts to hw?

 

[oilhead]

If you have hot water and heating selected, then the hot water will take priority over heating. If it gets really hot inside the boiler, then it suggests either a faulty DHW stat, a sticking flow switch, or air in the heatstore.