Potterton Profile 80e - Fully pumped - Pump running constantly

[Not-a-pro]

The pump connected to our Potterton Profile 80e is running constantly. I first noticed it when I heard the boiler fire up at 2am, when both the CH and HW are off on the LP522 timer.

I've had two engineers out from different companies. One said both valves (valve & head) and LP522 timer need to be replaced. The other said the PCB inside the boiler needs to be replaced.

From looking at the valves, both seem to turn on and off, okay.

Obviously I don't wish to have work done that I don't need. Is there some way I can test to see what the problem is?

 

[Agile]

How did you have two engineers?

Did you expect a free diagnosis so you could do it yourself?

I always charge to diagnose faults. If I did not then I would have a full time job diagnosing faults but totally unpaid.

If you were not paying them then it would not surprise me if they made up rubbish to tell you.

Tony

 

[Not-a-pro]

Hi Tony,

Thanks for coming back to me.

The first company services our boiler annually. When here two weeks ago, I mentioned that the boiler seems to come on during the night, then he noticed the boiler fire up while he was servicing it, when the CH and HW were off on the timer. So suggested the diagnostic. Then they sent out an engineer, who charged £120 for the diagsnotic. The engineer then came back with the quote for £600 to change the timer and the valves (& heads).

Since then I've been monitoring the boiler, and noticed the pump on nearly all the time.

Because the first quote seemed so costly, a friend of mine put me in touch with a plumber / heating engineer he knows well. He came round, had a quick look, and said that the pump is controlled by the boiler, so it's probably the PCB on the boiler, which he said costs around £50 for the part. For him to replace the valves he quoted £150, but said he'd do a full diagnostic first, for which I said I'd pay him, so he's coming on Monday morning.

I'm really just concerned that the correct thing get's fixed, and I don't get charged more than I should, or have things fixed that don't need fixing. So wondered if there is a way for me to work out where the problem lies. i.e. valves, or timer, or boiler PCB. I'm well experienced with wiring, etc, but not diagnosing heating / boiler faults.

Thanks,
Lance

 

[Agile]

That is extortion to charge £600 for a small repair. In fact you can buy a perfectly good Biasi M269 boiler for £500.

There are several things to look for that on your model.

Certainly motorised valves can fail but usually only the head needs changing, they are about £50 each.

Its rare but a timeclock can also fail like that. But you can remove the 522 body from the back plate and see if boiler still fires up.

To charge £120 for diagnostics ( I charge £84 ) seems very high and particularly when I don't think they have got it right.

Tony

 

[Not-a-pro]

Thanks Tony,

I turned off the power to the boiler, removed the 522 body, turned the boiler back on, and it fired straight up.

So it seems it must be either one of the valves, or otherwise the PCB on the boiler.

How do I go about testing the heads and valves? I assume I need to do more than merely disconnecting the heads from the valves.

Thanks,
Lance

 

[picasso]

It could also be the pump overrun stat sticking so have this checked before you change the pcb or valves.

 

[Agile]

You need to do a little testing with a multimeter on the wiring!

That's if you have one and are competent to use it.

Tony

 

[Gastips]

Hi, to test the valves.
Isolate your power and take out your 3amp fuse.
Open the wiring center.
Your valves will most likely have 5 wires. Brown, blue, grey, orange and earth ( depending on the valve).
The brown and blue only open the valve and a spring closes it. They sound like they are working so leave them alone for now.
The grey and orange are the main supply to the boiler through a micro switch in the valve. Grey live in to valve and orange live out to boiler.
To see if the micro switch is stuck and allowing power to the boiler all the time you will need to remove the wires from the wiring center and test for continuity. Obviously if the switch is ok it will show open circuit. If not then youve found your problem.
Hope this helps and saves on fitting parts you dont need. Any more help just ask. Good luck!

 

[ianmcd]

As Gastips says find out which grey and orange wires are closed circuit , you will have two of each , and replace the valve head from the one that is closed circuit, its not the pcb on the boiler it is an end switch on one of your zone valves

 

[Not-a-pro]

Great, thanks for all you help, guys. It was the HW actuator (head / valve switch). Cost me £60 instead of £600, thanks to all your guidance. If I could buy you all a Christmas beer, I would

Merry Christmas!

Thanks again,
Lance

 

[Agile]

Well if we knew where you were then there is bound to be someone close to you!

Tony