A Worcester-Bosch combination boiler.
I didn't know of this 'feature' when I committed to the new boiler, nor was it explained to me.
I will search for literature.
I'm fairly sure partner tried to maximise temperature immediately after installation and this was tops. I was unhappy then but only have only really needed heating this week.
Partner is mooching about in dressing gown, looking sad. We've had soup for the first time in ages. I have turned up room thermostat and will await events.
Is there a bypass loop close to the boiler?
This will be a pipe with a valve, which basically short-circuits the flow and return, to allow a flow path in the event that all other radiators are shut off.
If the bypass loop is too much open, then hot water returns to the boiler straight away, and it shuts down because it thinks things are hot enough.
The boiler will then short-cycle.
Cure is to shut down the bypass loop to absolute minimum, directing flow out to the radiators.
Isn't it the other way round, the bypass loop should be open so that water continues to circulate without the boiler having to cycle even if rad valves are not open?
I'm guessing that Helly has been sold a boiler with only one water temp setting, rather than separate temperatures for central heating and hot water.
The bypass loop is there to prevent deadheading the pump if all the radiators have TRVs, and they all close.
In many installations, there will we an always-on radiator ( eg bathroom towel rail ) in which case there is no need for a bypass loop.
Some bypass loops will have a PRV and will only open if the forward loop pressure exceeds a certain value.
Others can just be a dumb gate valve.
In the case of a dumb gate valve, it this is located close to the boiler and open too much, then freshly-heated water returns directly to the boiler causing the boiler stat to become satisfied and shut down, before much in the way of hot water has gone round the rads. As this cools, the boiler will fire briefly again, until it sees hot water returning again. In this case, the rads never become properly hot.
