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Central Heating

Boiler working, radiators come on but randomly all go off

Anonymous user 15/03/2024 - 2.52 PM

I have a 10 year old Potterton Main System 24HE. Boiler is working normally. Thermostat and programmer are working. I have a hot water cylinder and tanks in the loft in addition to the boiler. The boiler fires up and heats the radiators but after a few hours, it all goes completely cold. Always at night until morning and sometimes they do not come on at all. I have had 3 plumbers out so far, all got it working temporarily but once they have been paid and leave, it all goes off again! If I reduce the temperature on the hot water cyclinder to below 60c, I hear it all come on and the radiators heat up again. This has not happened before. I have been recommended to replace the boiler for £3500, not something I had planned for at this time of year so would rather avoid for another year. I do not know what to do to correct this. Any advice would be gratefully received.

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4 Answers

J.R.M Gas Ltd

Rating: 5 out of 5
Islington, London
Sounds like controls issue either mid position valve or zone valves. Also room thermostat or programmer
Answered22 November 2019
1

Anonymous user

If the boiler fires up for hot water like you say there is no problem with the boiler. It appears that the fault could be the 3 way valve, a wiring fault or an external control issue. The boiler is not at fault.
Answered22 November 2019
1

Anonymous user

Assuming zone valve(s) have been checked properly. Flow / Return temperature sensors could be faulty.
Answered24 November 2019
1

Bdm plumbing and heating

Rating: 5 out of 5
Islington, London
This is a control issue. It’s sounds like you have a 3 port system (y-plan) where your system is designed to give hot water priority. There are many reasons it could be failing eg. Cylinder stat faulty, cylinder stat not correctly attached to cylinder or heat loss due to lack of insulation or circulation issues. The best solution is check all above but also upgrade the system to an (s-plan) with a 2 channel programmer and 2x 2 port valves, this is a controls upgrade which is relatively straight forward allowing independent control of both ch/hw but is also a more modern way of controlling a system. You would keep with your existing boiler and cylinder but alter wiring, pipework and controls in the cylinder cupboard to accommodate.
Answered26 November 2019
0