Why does my combi boiler kick in on occasion, just for a few seconds. when (example) ... the time clock is set to 7C (during night) this was at midnight and is set to go from 21 to 7 at 10.30 the rads are cold the thermo is at 7C the room temp is 18C the outside temp is above freezing there are no dripping taps and none used in the previous half hour.
Is this normal?
In article , ss writes
As you haven't stated the make and model of boiler, how would anyone know?
In the spirit of the group however there is a class of combis designed to store a small amount hot water so that they are able to supply hot water instantaneously on demand rather than waiting for the usual run of cold before hot on a normal combi. Such a boiler will fire occasionally to maintain the temperature of the store and perhaps you have one of those.
If so, it's a useful feature, don't knock it.
My Glowworm does that whether it's set for heat and DHW or DHW only. If you look at the display while it's happening, the temperature gauge rises to its set temperature of 65C for the heating circuit. As has been said, it seems to be maintaining a small store of hot water to ensure a quicker response at the tap
Yes (for some boilers). Some have intermittent "tempering" programs that keep a small internal store of water hot - used to eliminate the lag for hot water is called for. Some have anti size programs that exercise the pump from time to time. Some allow you to turn these features on an off.
ok thanks for replies, makes a bit more sense now.
Some combi boilers have a small water store within (around 200cc or so). This is to reduce the waiting time for hot water to appear when you turn the hot tap on. It starts up at intervals to keep this heated up. Yours may be one of them
Based on my W-B, if it has a separate time control for hot water, setting the HW timer off will stop this feature running when its not needed eg overnight.
The other possibility: if it only licks in for a few seconds every 24 hours then it may be the CH pump running to prevent it seizing when unused in the summer.
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