No hot water from Megaflow

In December 2012 I had my boiler replaced and DHW and UFH are from a Vallant Eco Tech Plus 630. Installed and everything fine until today

I have an 11 year old Megaflow. Never had to do anything to it or had any trouble with it. There are two Honeywell valves, in line, on the pipe leading into the base of the Megaflow.

My plumber, who I have been using for the past few years, queried why there were two valves fitted. However reading this post //www.diynot.com/forums/viewtopic.php?t=180039&start=15
this appears correct.

The valve furthest from the megaflow is a Honeywell V4043H1056. The other is too near for me to read but it is a Honeywell.

I must confess the electrics for my DHW and UFH baffle me. I have separate UFH electrics but the fitted DHW clock has CH settings and if I don't run the two together I don't get any DHW. I guess that is a electrical problem but it doesn't cause this problem.

Having read the above posting and searched on here I checked the reset button, didn't make any difference. However when I turned the Megaflow thermostat down to minimum the Honeywell V4043H1056 value "moved" as I heard that sliding sound. Turned the thermostat up and it moved again. Meanwhile the other value started clicking. The pipe then became hot under the valves and we have hot water.

I have now noticed the led's on the clock and intermittently clicking and turning themselves on and off.......

Sounds like there could be a fault with the programmer but its all about electrical testing which you have to be competent to carry out. need to check voltage at both zonevalves & work back . could even be a bad N connection but if everything else works may not be. Should work independent to the heating & UFH though

swanny65 said:

My plumber, who I have been using for the past few years, queried why there were two valves fitted. However reading this post //www.diynot.com/forums/viewtopic.php?t=180039&start=15
this appears correct.

Click to expand...

as above & i wouldn't get this numpty to test it, i think he should just stick to changing your tap washers in future

Cheers for the replies. It is a problem with the programmer. Switched both programmes off last night and the CH led came on!!! Set it run as usual on auto, checked and came on fine at 05.30 this morning.

Obviously needs looking at as it also appears to switch itself off when it should be on and the intermittent on / off is overworking the valve.

As a aside do the 2 Honeywell valves on the pipe leading to Megaflow explain why the programme for CH needs to be on, together the programme for DHW, in order for the DHW to be heated. The UFH is not run via the programmer and has its own programmers? I cant see the point of having the CH programme otherwise.

bab said:

Sounds like there could be a fault with the programmer but its all about electrical testing which you have to be competent to carry out. need to check voltage at both zonevalves & work back . could even be a bad N connection but if everything else works may not be. Should work independent to the heating & UFH though

Click to expand...

Thanks for this - programmer tested by my plumber and it was a faulty electrical connection. Programmer and valves work fine now.