HELP NEEDED QUICK

[D_Hailsham]

its a 3 port motorised valve nr the cylinder.
I have tried the tests above and nothing seems to ignite the system. Just on the motorised valve there is a small lever on it "Auto" and manual what should it be on ? - have tried to do the test with it on either but still nothing.

1. Leave the switch in Auto. The Manual position is only used when filling the system
2. If the boiler does not light with HW only then either there is a fault in the boiler or the boiler is not getting 240v from the cylinder stat (The motorized valve is not in circuit on HW only).

There are 3 terminals on a cylinder stat:

C (Feed or Common): this should have 240v when the HW is turned on at timer.vI
1 This should have 240v when the cylinder thermostat is turned up high
2 This should have 240v when the cylinder stat is turned down low

If it passes this test, then the fault lies at the boiler end.

You asked about the purpose of the 3-port motorized valve. It is to circulate the heated water through the radiators and/or the HW cylinder as necessary. Water enters the valve at the bottom of the Tee from the pump, it is then routed out of either or both of the side arms of the Tee as required. One arm goes to the radiators, the other to the cylinder

could our problem lie with the on off switch for the heating and water?? its wall mounted with a timer on the Left and two sliding switches on the right one for the water the other for the heating.
Note that the timer part of this hasnt worked for a few months and the heating/water had to be switched on/off manually - i have taken the box off and checked the push on connections - they seem fine -also power going to the cables ok.. I did notice that near the timer (back of box) there is a two wire resistor?? type thing light grey.

The voltage checks should tell you. If there is not 240v at the C terminal of the cylinder stat, then the time switch may be faulty.

To be logical you need to start testing at the beginning, i.e where the system obtains its 240v and progress forwards through the timeswitch, selector switches, thermostats etc until you find the fault or reach the boiler.

 

[hi-spec plumbing heating]

wouldn't worry now that was 3 days ago

 

[zimmers]

I had this problem last year and found it was the gas valve which i didnt expect to be the main issue,the o/heat button was also knocking the pilot out but when i renewed the g/valve it was ok

 

[D_Hailsham]

wouldn't worry now that was 3 days ago

I know, but there was no sign that the problem had been solved.

 

[hi-spec plumbing heating]

i do agree, but if they can't be bothered to come back why should we.