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Michael
Michael, Home Appliance Technician
Category: Home Improvement
Satisfied Customers: 9568
Experience:  Home Appliance Technician
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Potterton mf rsl 60 boiler fails to start in the morning unless

Customer Question

Potterton mf rsl 60 boiler fails to start in the morning unless the boiler thermostatknob knob is turned off (0 position) then back on again. It then functions normally!
Submitted: 2 years ago.
Category: Home Improvement
Expert:  Michael replied 2 years ago.
Michael :

good morning

Michael :

this is actually a failed control knob (thermostat)

Michael :

the contacts inside have become intermittent as will happen with age ;-)

Michael :

hello?

Michael :

I will switch us to Q & A it may work better,

Expert:  Michael replied 2 years ago.
Our chat has ended, but you can still continue to ask me questions here until you are satisfied with your answer. Come back to this page to view our conversation and any other new information.

What happens now?

If you haven’t already done so, please rate your answer above. Or, you can reply to me using the box below.
Expert:  Michael replied 2 years ago.
Hi Alan,
this is actually a failed control knob (thermostat)
the contacts inside have become intermittent as will happen with age.
Do you need a source for the part?
Thank you
Tech Michael
Customer: replied 2 years ago.

Thankyou - I will try to get a replacement thermostat control knob and replace it. . .......i will advise in a few days time it it fixes the problem.

Regards,

Alan

Expert:  Michael replied 2 years ago.
Sounds good Alan, please rate and I will stick with you until this is working as it should, have a nice day;-)
Tech Michael
Michael, Home Appliance Technician
Category: Home Improvement
Satisfied Customers: 9568
Experience: Home Appliance Technician
Michael and other Home Improvement Specialists are ready to help you
Customer: replied 2 years ago.

Hi Michael - have sourced and fitted a new thermostat control (potentiometer they call it) it came with a wiring harness so just had to fit it and connect the 2 plug connectors. All seemed to work OK however this morning when the system is cold the heating did not come on untill I turned the the boiler thermostat knob to off (0 position ) the on again. .....the the boiler came to life! So the new part has not made any difference.

Customer: replied 2 years ago.

Just to clarify - changing the control switch has made no difference the boiler still fails to start unless I turn the control knob to off then back on again......any other suggestions?

Thanks in anticipation,

Alan

Customer: replied 2 years ago.
Relist: Inaccurate answer.
I have now replaced the boiler part that Michael advised was the cause of the problem but it has made no difference the fault is still as described in my original question.
Expert:  Plumberpro replied 2 years ago.
Hi . I think you have a faulty motorised valve . when they get weak the motor doesn't pull over straight away.get back to me and I can run you bthrough a test
Customer: replied 2 years ago.

Hi - thanks for following this up. Probably best to advise you ths is not a bog standard set-up..........we live in a covverted bungalow, so there is no loft space to house a header tank so the hot water tank has a header tank as part of it. The system works such that the water in the hot water tank is shared with the radiators and we get hot water from the mains supply passing through the tank on it's Way to the hot taps. Happy to test the motorised valve if you advise how. I think the fault lies with the boiler though cos I was up this morning when the heating comes on. The radiators get warm as the water in the hot water tank gets circulated round the system which tells me that the motorised valve must be working.......the boiler should fire up at this stage to bring the tank and radiator water up to working temp. However it fails to start - normally I switch the boiler temp knob to off then on again and it then fires up but nothing happened today. I left it for 5 mins or so and tried again this time it's worked ! My guess is there must be some sort of sensor on the boiler which is failing to trigger till the circulating water from the hot tank warmed the boiler enough to make it work. Hope this makes sense!

Expert:  Plumberpro replied 2 years ago.

Hi . just going to look up your boiler manual will be a few mins , thanks. Mybthinkingvis it has to be the boiler , as it seems to reset when you turn the boiler to off on the boiler stat. This can only be resetting the overheat stat. Why the overheat stat could be operating could be the permanent pilot is heating the boiler overnight ( maybe boiler a little blocked \ sludged) and the heat isn't dissipating .

Customer: replied 2 years ago.

The boiler was Stone cold this morning - which is the condition from which it fails to start. Once the

Expert:  Plumberpro replied 2 years ago.
Its a strange one . maybe the PCB , but I need to download a better manual PDF as the last one is unreadable . few mins ,please thanks
Expert:  Plumberpro replied 2 years ago.
Hi . is the pump wired directly to the boiler as it has a pump overrun built in?
Also are there any fault code led,s lit?
Customer: replied 2 years ago.

  • Just been to look - there are 2 pumps in the aring cupboard, but I cannot tell IF one is wired to the boiler as an overrun, but I have noticed that when the system switches off at night if the boiler has been working then one of the pumps continues to run for 5 mins or more. No LED lit on the boiler. There is only 1 led on the boiler if that is lit (Red) then the reset Button next to it has to be pressed to get the boiler to work - this has only happened once or twice years ago.

Expert:  Plumberpro replied 2 years ago.
To be honest these boilers arnt designed to run with direct / primary store systems , well that as what it says in the manual . well its got to be the boiler as turning the boiler stat off then back on gets it going . I am thinking that it is the boiler PCB , but its an expensive part , so if you want I can phone potterton in the morning and try to get a heads up from there technical support ?
Customer: replied 2 years ago.

That sounds like a good idea - I'll be otherwise occupied for most of the morning so will come back to this as soon as I can - thanks so far. - Alan .

Expert:  Plumberpro replied 2 years ago.
Ok Alan , speak tomorrow then , Toby
Customer: replied 2 years ago.
  • Hi Toby - am back home now so can continue the chat with you if you have spoken to Potterton tech support . I rang potterton tech support myself - thought they wouldn't commit 100% he was pretty sure it was the pcb - so I ordered one which arrived yesterday , I fitted it and can confirm that the heating came on automatically this morning. . .....problem fixed - excellent. - Thankyou Toby.
Expert:  Plumberpro replied 2 years ago.
Your welcome
Expert:  Plumberpro replied 2 years ago.
Hi would you mind rating me please , thanks
Customer: replied 2 years ago.

Hi Toby ,

I'd like to give you an excellent rating however when I try that, the system wants me to pay another £21 which I am not prepared to do.

Expert:  Plumberpro replied 2 years ago.
Hi . I only recieve a payment when you rate me , so as yet I haven't recieved anything yet. But it is in dollars and not pounds . if you are still having problems with the system , let me know
Customer: replied 2 years ago.

Hi Toby,

Tried again this morning to give you an excellent rating however the system displays a popup box indicating that I have already rated the expert - Michael who started this off and asked me to rate him, promised to stick with it till it was resolved but I could not get anything more from him. ....since I was not not happy and obviously wanted to resolve this took the 'not satisfied with your Expert' option. You took it up.....but I suppose Michael has had the credit for this! Don't know how to rectify this unless you can tell me how to redirect the credit to you .

Expert:  Plumberpro replied 2 years ago.
Yes , that must be what happened , but never mind , I'm glad you got it all sorted out . have it as a Christmas present from me , so don't worry .all the best, Toby
Customer: replied 2 years ago.

Very kind thankyou. . ......all the best to you and Yours this Christmas

Regards,

Alan.

Expert:  Plumberpro replied 2 years ago.
Thanks Alan . you too ,have a good one , Toby