Potterton Flamingo 20-30 CH not working but getting hot wate

I have a Potterton Flamingo 20-30 boiler,it working fine with hot water but it fails to start the CH system,also when the hot water starts my downstairs radiators get warm.

check the three port valve

Thanks you very much for your reply, it was the three port valve , i have to manually switch it to CH and my CH started working, Does this mean that the 'three port valve' is faulty and need changing, also as i manually switched it to CH , my CH started but the switch is back to Hot water is that right behavior.

Thanks you once again for your reply

Hello there guys, seems you know loads about CH problems!

Please help me with a problem my family has been having, me and my dad have been trying for a while to fix it...

Basicly one day we found the heating wasn't working, not firing in the boiler, but the hot water was working fine, firing in the boiler and it worked.

We've replaced the thermostat and tried every way of wiring it up, didn't change the problem. We have earth + neutral + live. Three wires.

Now we've replaced the Honeywell three way powerhead and pipe system. (new switches/motor and everything) checked for leaks, still not working...

We've replaced the automatic programmable switch next to our boiler and it still doesn't work.

We tried to wire up both netrual and live by twisting the two cables around each other, in hope of by bypassing the thermostat, didn't work...

Still not working.

We've almost gave up, can you please help us?

Potterton Flamingo is the boiler. I notice you're from Berkshire also!

Thanks, ever ever so much!

Please respond ASAP, getting a little chilly here.

Best Regards,

Laurence

You seemed to replaced all the obvious things it could be even though all are possible to test to see which is faulty before replacing! You should have come here first!

You say you tried to link live and neutral suggests that you dont really understand the basics.

Time to call out a heating engineer?

Well I should have but no harm replacing them anyhow. Makes sure I guess.

I read that on some forums, to link them together. What's the switch do anyway complete the circuit?

No, sorry we can't do that. Little low on money currently after some car problems..

Thanks for the reply!

CH works like this.

Power is sent from clock to the room stat are you getting power here?

When the roomstat calls for heat i.e makes the wires it sends power to the motorised valve. Which motors open and makes a switch bringing pump and boiler on. You need to see where power is and isnt being sent to. Easy only when you know how.

If all was working fine before hand then its usually always down to one of the three parts you have changed. Which suggests it might not have been done correctly.

And not being funny but all the parts you have bought would have paid for a hetaing man to atleast tell you whats wrong!

Got ya, there is power at the stat.

The powerhead is working, my dad says he tripple checked the wiring.

A heating man might just cost the same, but you would need to add at least one of the parts on top...

He phoned a plumber and they said to drain the system from the lowest rad incase it got full of air?

This a good idea?

Can't see what draining the system will achieve. If you've changed any pipe work, then it is possible there is air in the system that needs removing. However if you do drain and refill please ensure the lever on the side of your 3 port valve is on the latch that holds it in the mid position. This ensures water goes into both the HW side and the CH side.
Don't forget to bleed the pump as well as radiators.
Going to your initial problem I would say it centres around the 3 port valve.
The valve itself sometimes fails due to either a faulty motor or faulty micro switch, but you've replaced that so I think I'd be looking at the wiring. The valve has 5 wires, the green earth and blue neutral need not be explained, but the white, grey and orange do need a little explantion.
The valve moves over two sections to get to CH only and when it does it supplies power out through the orange wire to fire the boiler.
If this does not happen with a new valve it suggests the valve is not moving across the second section.
For the valve to move from HW position to mid positon, the room stat supplies power to the white wire. This is a easy test using a multimeter in the 10 terminal box. You should be able to indentify the white.
The second section is not quite as simple. When valve is in mid position HW and CH are receiving water, but only until one side gets satisfied.
Now this is usually HW and the valve then moves over the second section to the CH only position. Now to do this, it's down to there being power on the grey wire.
So where does the grey wire get its power from. Well it needs to have power when there is no call for HW so the cylinder stat has a third terminal so when HW is satisfied power is diverted to the grey wire.
Good! but what if HW is not switched on?, the cylinder stat is not fed with power.
Well it's been catered for! There is progammer terminal called HW OFF and a wire is fed from this terminal also to the grey wire.
This means that with both HW and CH not switched on at the programmer, the grey wire must be live. Again easy to test in the terminal box.
It's possible when wires are replaced a fault may be introduced, I'm thinking wires may be too far in terminal and insulation is causing problem and I'm thinking the valve wires including neutral.

Thanks ever, ever so much for your post! It's helped us both greatly!




Right my dad has checked all the wires, and he gets a signal on all at the right time other than the white wire, which doesn't get anything any time - While I made sure the heating was on, on the programmable switch (next to the boiler) and while I was flicking the thermostat on and off every three seconds.

Red(maybe brown), blue and earth are the only ones going to our new thermostat.


Red(maybe brown) into "Marked L"

Blue into "#2"

Earth into the top left corner, marked earth. (assume earth is earth)




Can you help us on this problem?

I hope we understood you correctly.


Thanks ever so much!

Regards,

Laurence

Well if the white does not become live the valve can't move across the first section.
Now the room stat is basically just a switch, thats a live wire going to it from the programmer and with CH on it will always be live at the room stat.
Then the wire coming from the room stat to the white wire is called a 'switched live' ( not neutral)
This of course means two wires only, but there are room stats with three wires. The third wire is in fact a neutral usually coloured 'blue'.
While a wire going to a load is 'live' or 'switched live' the wire leaving the load is a 'neutral' so why a neutral in a room stat which basically a switch'
In order to have better control of room temperature there is within some room stats a miniture heater which is a 'load' so a neutral is required.
I'm not aware of room stats having a earth, so I reckon yours could be 'red' 'yellow' and 'blue'.
The live from the programmer could be either the red or yellow and you need to verify which one it is then put that to the L terminal and the other to SL (switched live) terminal and blue to N terminal.
I don't know what make or model of room stat you have, but you can usually find a web site that gives all the detail.
Good luck! hope you soon get it solved

Just another thought. What colour is the wire in the ten terminal box in with the white. Whatever it is, it's got to be coming from the room stat and will be the 'switched live'

Hey Mandate, thanks ever so much for your posts!

We bleeded the whole system, from the bottom two rads and it still didn't work, which I thought but my dad seemed to think that it would.

Turns out the green/yellow cable was a switchable live... not earth, wired up different in the room thermostat and it works perfect now, rads nice and hot! We're just bleeding out the rest of the air now.

You solved the problem!

Now the real problem is what caused this all! Hehehe.

Thanks ever so much for your help, greatly appreciated!

Take care!

I would say your problem was down to the old valve. Maybe a duff micro switch or more likely the motor. These motors drive and hold the quadrant at the CH position so they energised for hours on end and if CH is the last thing to be switched off, it does not return to the HW positon as you may imagine. The power to boiler is cut off but the valve stays put.
However problem solved and look what you've learned for the future.

Yeah that's what I was thinking, why we got a new one.

Really so it's better to turn on HW before you turn off the CH? (then turn both off)