The system is longer than the boiler
Between the boiler firing and a room getting warm there is a pump, a diverter or motorised valve, a programmer, a room thermostat and its wiring, the valves on each radiator, an expansion vessel and the water itself. A fault anywhere along that chain arrives as the same complaint, no heat, and those parts are nothing like each other in price. Working out which link has stopped is the job.
How we work back through it
- Is a demand reaching the boiler at all? Programmer, room thermostat and wiring come first.
- Does it fire and drop out, or never fire? That separates ignition and sensing faults from control faults.
- Is water moving? Flow and return temperatures show whether the pump is shifting anything.
- Is the demand going where it should? Valves are the usual reason for hot water and cold radiators, or the reverse.
- Is pressure holding? If not, water is leaving the system or the expansion vessel has lost its charge.
- What does the water look like? Black water explains repeat failures better than any fault code.
When the system is the fault, not the part
A pump that seizes twice, a valve that goes again, radiators cold along the bottom, air that keeps coming back – that is not bad luck with parts. Corrosion debris circulating around a system wears pumps and valves and blocks the narrow passages in a modern heat exchanger. Fitting the same part again treats the symptom. A magnetic filter on the return does more for a system than an oversized pump will.
Repair or replace
Repair is the sensible call on a boiler that is not especially old with a part still in production. Replacement makes more sense when parts are obsolete, when there have been several separate failures, or when the fault is a heat exchanger, because at that point you are spending a large share of a new boiler on an old one. We will tell you plainly which you are in. New boilers start at £1,900 + VAT supplied and fitted for a straight combi swap, same type and position, including the boiler, flue, fittings and a system filter.
We work on Worcester Bosch, Baxi, Vaillant, Ideal and Glow-worm. Fixed price agreed before work starts, no call-out fee. Call 0161 515 9977 or email admin@nelsonplumbing.co.uk.
