Some Real help neded

[dgrallying]

Hi All

This problem that i am going to list has now been ongoing for about 2 weeks now, so to say that i am getting a hard time from er-in-dors is a bit of a understatement!!!

the problem was originally due to the three port valve i had was sticking and thus making the temp rise to about 28 degrees, so as a cut back exercise i decided to change the valve as i would save money on heating bills, well at least thats what i thought...

I changed the valve and body from an original TOWER type to a DRAYTON type, the wires were the same, therefore i changed them in the joiner block like for like.

i couldn't get the boiler to fire up once i had done this so i had a electrician attend to make sure i hard wired it in correctly, i had.

i then set to and blew out all the air in the system as it is a fully vented system, the boiler then fire up for about 60 secs and then went off again, I then carried out the fault finding as of the book, and it indicated a PCB fault, i then changed the PCB for a new one, and still the same problem.

The problem that i seem to have is that when you call for CH on the room stat the boiler MAY fire up for approx 60 secs and then cut out, although the 3-port valve is in the H position, when you call for HW on the programmer the 3-port valve will go to the W position and the boiler will fire up until the cylinder stat cuts it off. If i call for both CH & HW the valve will move to M and the boiler will run fine and i get heat around the house until the Cylinder stat cuts it off again. if i call for just hot water the valve will move to W and the boiler runs fine until the cylinder stat cuts it off.

I had a Plumber look at it today and he said the cylinder stat was too high and was making the boiler get too hot and causing it to cut off and thus not making the CH get hot.

so, i left it just turned to CH and 4 hours later the boiler was stone cold and when it was called on the room stat and programmer to fire up it would not fire up, when it did finally fire up it only fired up for approx 60 secs again and then switched off.

CAN SOMEONE PLEASE HELP???

So you know what i have, i have listed the parts below:

Boiler: Potterton Kingfisher MF cf80
3-Port Valve: Drayton
Programmer: Horstmann Centaur Plus C27
Room Stat: Drayton Digistat 1

i am really getting to the end of my tether with this!!

 

[jackthom]

Take a look at this diagram http://www.octaveblue.co.uk/c_heating/ch_only.htm.

When CH only is selected, check that the boiler is receiving "demand" via the orange wire and the pump actually runs.

 

[Rob]

Better to get a heating/boiler man rather than a plumber out to have a look.

If it works ok on HW then I would assume the boiler is working ok and is an external fault.

If its not even firing up for htg then check the wiring or again get a heating engineer to have a look. Electricians aren't always the experts on heating control wiring.[/i]