very hot water and intermittent CH?

[skipper_2]

I don't know if anyone can help me with this problem but any advice would be appreciated.
I have a Y plan system with the dreaded Potterton suprima boiler, a ppt tank stat and ptr room stat and 2 2 port motorised valves.

The first problem is the water never stops heating, I assumed that the tank stat was faulty so put in a new one, ( I also replaced the HW motorised valve as it was was melted when I moved in so)but to no avail. The light on the stat says water temperature reached but it never stops calling for heat?

The other problem is that sometimes the heating comes on as it should and other times when it is supposed to come on it runs for a few minutes then stops and keeps repeating this sequence of firing up the boiler then stopping. Also sometimes when the heating is turned on, the valve opens, the pump starts but the boiler does not fire up and no flashing light to call for heat? However, when the water is on the heating is fine, but as I say the water never stops heating.

I have searched the forum but to no avail. If anyone has any suggestions they would be greatly appreciated as the only way I can successfully have heating on is by having scorching water

Cheers
Paul

 

[cross thread]

sounds like the wiring is wrong you will have a diagram for " s plan "with the new valve

 

[baxpoti]

Or you've left the immersion heater on

 

[skipper_2]

I have looked at the wiring diagram and although I know very little about electrics, it doesnt look like the diagram

It cant be the immersion heater as there isnt one.

The only thing I dont understand is that the water problem has been like it since I moved in but the heating thing is quite recent?

 

[bster]

check that hot water on terminal from programmer is connected to common (C terminal on cyl stat) and that terminal 1 on the cyl stat is connected to the brown wire on the 2 port valve ( hot water).

 

[bster]

is it a PTT and not a PPT?

If so then terminal 'H' (identified in the last post as terminal '1') is the feed to the brown wire of the 2 port valve.

 

[skipper_2]

yes sorry I meant ptt, will check what you said, cheers.

 

[bster]

PTT1 or PTT2 or PTT100?

 

[skipper_2]

PTT2 so it says on it

 

[bster]

and the programmer?

 

[skipper_2]

EP2002

 

[bster]

The functional flow should go as follows

PROGRAMMER - HW ON= Terminal 3 (this wire then goes to the cyl stat -TL)

Cyl Stat: in = 'TL', out = 'H' (H wire goes to brown on 2 port valve)

2 port valve (if honeywell v4043) Brown



check that the above wiring is correct and report back!

 

[skipper_2]

cheers, will do tommorrow and report back.

 

[bster]

There is a plumber on here from Cardiff, cant remember his 'name' though. He might be your last resort before xmas...if you can find him!

I'm from Newport BTW

 

[skipper_2]

I have had a look at what you said and the results are as follows

There are 5 terminals on PTT2 from left to right H C L TL and N

According to what I can see they go like this

H = SLW C = Grey on valve

L = 3 on programmer

TL = Valve brown and N to neutral

I tried connecting H to Valve brown and TL to 3 on the programmer and L to SWL but the thermostat kept going click click click and lights were flashing

I am not really sure if cable 3 really is cable 3 as i dont know how to get the front off the programmer. I am just going by wiring diagram I have for the control box.

Any thoughts?
Cheers Paul