As I said it would be better to fit one pump per boiler with a non return valve on the return. Then the sequencer will be able to properly control the boilers so that just one can work without the pump still sending half of the flow through the off boiler.
Fitting a spring return motor valve to the return connection to each boiler would achieve the same result but enable a single pump to be used. But we think your pump is undersized already so thats not a recommended option. Furthermore the valve would need to be connected so that it remains open for the pump over run period.
Hello, I am the owner of the property and 2 years down the line i still have to go upstairs and stick a pen into the reset buttons every morning and often during the day too...
the plumber who installed this system is the nicest guy anyone could wish to meet and is meticulous to the extreme. and is my friend. but i have to get this issue resolved.
it appears that he has created an llh with check valves and boiler isolation valves, but am i right when i say that the llh will not work unless it mixes with some of the cool return flow. Is this what is reffered to as a shunt? I am no plumber, just trying to understand what is going on.....I have offered to purchase another Alpha pump to put in the return.
one factor which i still find odd is that there is virtually no hot return the temperature never reaches anywhere near even 40 degrees which has rendered the sequencer useless as it never shuts down.
also there is no flow control valve in the hw feed to the megaflow which seems to be the path of least resistance when the boilers do fire and the boilers shoot up to temperature when there is no ch demand. but they do modulate nicely in this situation as one would expect. when the ch demand is put on the boilers take a gulp of cold return water which i can only assume confuses the hell out of the boiler and contributes to the f25 error, i dont know how the software actually determines the f25 fault.. this could be the first step in solving this problem.. are there any of you guys who for a modist fee would head to the midlands to see and fix this rogue installation
