I am troubled by my boiler repeatedly firing up for very short periods od less than a minute when I have used less than a sink of water, and doing this 8 times in 25 minutes even though I had not used any more
I am thinking that the cyl stat detects the drop in temp near the bottom of the cyl (stat is mounted 300 mm up from the bottom, coil tappings are at about 100mm and 450mm up, was fitted Sept 2002 and is modern blue/green foamed)
I am considering the idea that if I had a cyl stat with a big gap between "off" and "on" temps, it would not start the boiler up until the bottom of the boiler had gone cold, so it would not fire up so often. the cylinder is plenty big enough.
The boiler is a Vitodens with the coiled stainless tube HEX, so it does not have much mass.
I have not got pipe thermometers but I have tested the temp of the tap water and it is coming out at the temp set by the cyl stat
Any comments or suggestions?
the cyl stat is a (new) Honeywell L641
Working parts of installation are new
Boiler is Vitodens 100 Compact (modulating)
Open-vented
Pump is Grundfos Alpha + with 28mm gate valves (self-modulating)
Pump runs for 10mins after final call for heat ends.
Boiler stat is "normal" 60C
Cyl stat is set to 50C (I have been turned it down a bit to see if it helps, but the short-cycling still occurs when the cylinder is almost, but not completely, full of hot)
This is a different approach to solving the problem I reported earlier.
I am thinking that the cyl stat detects the drop in temp near the bottom of the cyl (stat is mounted 300 mm up from the bottom, coil tappings are at about 100mm and 450mm up, was fitted Sept 2002 and is modern blue/green foamed)
I am considering the idea that if I had a cyl stat with a big gap between "off" and "on" temps, it would not start the boiler up until the bottom of the boiler had gone cold, so it would not fire up so often. the cylinder is plenty big enough.
The boiler is a Vitodens with the coiled stainless tube HEX, so it does not have much mass.
I have not got pipe thermometers but I have tested the temp of the tap water and it is coming out at the temp set by the cyl stat
Any comments or suggestions?
the cyl stat is a (new) Honeywell L641
Working parts of installation are new
Boiler is Vitodens 100 Compact (modulating)
Open-vented
Pump is Grundfos Alpha + with 28mm gate valves (self-modulating)
Pump runs for 10mins after final call for heat ends.
Boiler stat is "normal" 60C
Cyl stat is set to 50C (I have been turned it down a bit to see if it helps, but the short-cycling still occurs when the cylinder is almost, but not completely, full of hot)
This is a different approach to solving the problem I reported earlier.