Fitting new 5111603 PCB to suprima 50

[Grindstone]

Hi, I'm new to this forum, but have sen much discussion regarding this and would like some advice if possible.

After having the lockout problem above I bought a digistat room thermometer in the vain hope that leaving the boiler on but controlled by the 'stat would remove the problem. All looked to be working, but then in a separate incident the lights fused in the house. Got an electrician in who got everything back on, (short in a upstairs light). But the boiler would not light.

Got a plumber out who diagnosed a new PCB as above. He fit that, still no heat. He then said the clock was broken, so we got a replacement clock, the new one. All working now, however the problem is that the water must be on to make the heating come on! The thermostat works to send a demand for heat, but will not turn the heating off, it just gets hotter and hotter until I turn the water off, then the boiler goes off.

The plumber has been back twice, he still has no idea why as essentially all he has changes is the clock, just slotted over the existing connections, and put a new PCB in. As I said it was all working perfectly before the power cut apart from the lock out problem.

Can anybody offer any advice?

 

[cowley]

What type of clock/programmer?.
Has it been set to 16 program setting?.

 

[superdupergasman]

Look in the instructions for the clock and it will have a section talking about gravity system set up or fully pumped.

Yours will have been set to the gravity and needs to be changed

This could be in the form of a small tab that has to be moved of a little slot that needs to be twisted.

 

[Agile]

EDIT Yet again one of this mad Mod 10 has deleted part of my posting without comment or explanation so I have consequently deleted my free advice on what might be the problem. Its time the site owner sorts out these people he gives editing rights to!!!

I am not very impressed by your "plumber" who has apparently made TWO visits and still cannot tell whats wrong with a simple control circuit. I hope he is not charging you for his imcompetence!

Tony

 

[Grindstone]

The clock is a Drayton with programmable settings for water and heat, currently the heating is set to be permanently on witn the hot water on timer. When the water goes off so does the heating. The thermostat is a digistat from drayton and is programmable and can be overidden manually to force a demand for heat by increasing the temperature. This works to get the heat on but when the temperature is reached doesn't turn the heat off.

I'll take the clock off tonight and check for the tab, will it cause an issue if it is set to the wrong position, i.e. can I change it, see what happens etc?

Thanks for the advice

 

[ChrisR]

can I change it, see what happens etc?

Yes, no probs.[/quote]

 

[Grindstone]

Ok, I took the clock off, behind it there is a plastic tab and below that a p, I guess for pump and gravity marking. The tab pulls off and you then see three connectors, replacing the tab allows a one connector to be visible at either end, so the middle one is always obscured.

It was set so that the one over the P was covered, I've moved it so that the P is visible. Put it back on the wall, and now there is a change to the clock.

In the first fitting the heating and water controls worked indepepently of each other, (although the heating control didn't fir up the boiler, only the water did). On this setting the heating control lights up the water and the heating. Heating comes on when the thermostat demands heat, but still doesn't turn the heast off when room temperature is reached.

The original clock, (this is a new replacement) was a Drayton that has independent heat and water controls, but the programme only allowed both to come on at the same time or off at the same time. You coukld set both to constant, off or once only.

The new clock allows all the same but allows the water and heat to be programmed independently. Hope that's clear?

Can you help, coould it be the wiring that is now not correct for the new clock? According to the plumber this was an upgrade but straight replacement part, fitttings are exactly the same, clock looks the same.

 

[Grindstone]

Sussed the clock, on the gravity setting it will not allow independent heating of water, so I need to change this back the way it was, which still leaves the same issue, i.e. heating control won't turn the boiler on, although it needs to be on, hot water must be on to get the heating on and then the thermostat must demand heat, BUT then the heating won't turn off when the heat passes the thermostat mark.

The thermostat is a digistat programmable one, looks to be working ok i.e. flame comes on to indicate demand for heat and goes off when the heat is reached.

Clock is a drayton LP522, Boiler is a potty50 with the new PCB. My plumber still does not know why this is happening and its driving me mad.

Anybody good with conundrums?

 

[Grindstone]

Hi, sorry to re start an old post, but I still have the same problem. Three plumbers have been out to this and still no further on.

Essentially all that has been changed to a system that was working, is an upgraded PCB, so the lock out problem has gone. And an upgraded clock that allows independent water and heat.

If the heat is on its own, no heat!
Turn the water on as well and the thermostat down, no heat or water.
Turn the thermostat up, heat and water, but once the temperature gets past the thermostat, despite it turning off, the boiler stays on and the radiators get hotter.

Can anybody advise, or know of a competent plumber in the Oldham area who can come and fix this?

 

[Agile]

As we told you before, the system seems to be wired wrongly.

If its wired using a wiring centre which is like a double sized blank switch box then it may not be too difficult.

If its wired into odd connector blocks either behind the programmer or in a single size box then its usually better to rewire it from scratch.

Others charge on a per hour basis which is like a blank cheque. We like to charge on a fixed price basis but as these situations can be quite time consuming, I would be inclined, without seeing it, to quote about £120 in our local area.

Perhaps someone on this forum will be able to cover your area.

Tony

 

[MANDATE]

Do I take it that it's designed to have HW or CH independent of each other.
In which case do you have any motorised valves, none appear to have been mentioned.
Unless I've got it wrong, it sounds like a 3 port mid position valve that will not go beyond or stuck at mid position

 

[Grindstone]

There is a three way motorised valve. It will move through all positions I think. Leastways when the heating is off its at one end and it will move through to the other end.

Is there anything I can check here to prove its working?

Thanks

 

[Grindstone]

Tony,

Sorry I never got to see what I guess was your original post, only what is on here now. Its wired into connector blocks, so I guess a re wire may well be what is needed as you suggest.

I guess this means it can be incorrectly wired up but still sort of work as it is now?

Anyway happy to pay £120 to get this resolved if anyone is in the area and can resolve this.

 

[MANDATE]

To get CH only the valve has to move fully across to the CH only position, which is in two stages, not only that but it has to supply power to light the boiler.
The two stages rely on power being available on the valves ‘white’ wire supplied via the room stat. to cover the first stage.
Secondly power must be available on the valves ‘grey’ wire, supplied by the satisfied terminal of the cylinder stat. to cover the second stage. This leaves a problem if the HW is not on, cause that power can’t be there. So an additional wire is supplied from the programmers HW OFF terminal.

So you could test to establish (a) is the valves ‘grey’ wire live when HW is Off and again if HW is on but satisfied, then
(b) Is the valves ‘white’ wire live when CH is on and room stat turned up.

You might be able to tell by trying
(a) HW only: (boiler lights)leave for 20 secs to give time for motor to unwind by return spring.(boiler lights)
(b) (boiler stays lit)Put CH on (so both are on). Motor/Valve should move to mid position (stage 1)
(c) Now turn HW off. This is where the ‘grey’ wire takes over and moves the motor/valve forwards to CH position. During this the boiler will in fact stop for a sec and relight. This is due the cylinder stat being no longer involved and the power to light boiler now comes from the valves ‘orange’ wire. (via a micro switch).
If the valve moves as it should, You will know the wiring from room stat and the HW OFF terminal is ok.If boiler does not light, problem will be micro switch.
If the valve does not move as it should problem can be wiring, motor, or micro switch, or stiff valve spindle.
If it does nothing to help solve your problem, it gives some insight into how these mid position valves operate.

 

[Grindstone]

Ok, so this is what happens:

HW and CH off, switch points to the bottom at the letter H
HW on on its own, switch points to the top at M
HW and CH on together switch is midway at W
CH only switch is back at H, boiler turns off no heat.

So does this confirm its the "micro switch" and if it does, where is it and can I change it, or do I need professional help, albeit I can now educate them thanks to your help?