Heating works but the taps run cold? On a combi that is almost always the diverter valve or the hot-water thermistor, and both are same-day repairs. Fixed £95 diagnostic across every EH postcode.
Boiler with no hot water — Edinburgh repair?
If your Edinburgh combi gives heating but no hot water, the diverter valve is the most likely cause, followed by the hot-water thermistor, a blocked plate heat exchanger or a failed flow sensor. A vetted Gas Safe registered partner engineer diagnoses it for a fixed £95, deducted from the repair, and carries the common Worcester, Vaillant, Ideal, Baxi and Glow-worm parts on the van.
Key points
Diverter valve stuck on central heating — the single most common cause
Hot-water thermistor reading wrongly and shutting the burner down
Plate heat exchanger scaled up (more common in hard-water Midlothian fringe supplies)
Flow sensor or flow turbine not detecting the tap opening
Most likely causes
Diverter valve stuck on central heating — the single most common cause
Hot-water thermistor reading wrongly and shutting the burner down
Plate heat exchanger scaled up (more common in hard-water Midlothian fringe supplies)
Flow sensor or flow turbine not detecting the tap opening
On a system boiler: failed cylinder immersion, motorised valve or cylinder stat
Check these before you call
Check the pressure gauge reads between 1.0 and 1.5 bar cold
Confirm the boiler fires when a hot tap is opened — listen at the boiler
Try a different tap, in case a single tap cartridge has failed
Note any fault code on the display before you call
How the visit works
Fixed £95 diagnostic, booked to a two-hour window
Fault traced to the component — no speculative part-swapping
Written quote before any repair begins
Common Worcester, Vaillant, Ideal, Baxi and Glow-worm parts on the van
Because the diverter valve that switches flow between the radiators and the taps has stuck on the heating side. It is a mechanical part, it fails gradually, and on most combis it is a one-to-two-hour replacement costing £220–£340 all-in.
Can I use my heating while I wait?
Yes, if the boiler is firing for heating and there is no leak, smell of gas or fault lockout. Boil the kettle for washing and avoid running the hot tap repeatedly — repeated cycling can worsen a failing valve.
How much does a boiler repair cost in Edinburgh?
Heatscape charges a fixed £95 diagnostic across every EH postcode, deducted in full from any repair carried out on the same visit. Out of hours (after 6pm and weekends) is £140. Most common repairs land between £120 and £420 all-in including parts and labour. If a repair would cost more than about £600 on a boiler over 10 years old, we quote a like-for-like replacement at £2,295 instead.
Are boiler repairs guaranteed?
Every repair carries a 12-month workmanship guarantee, and manufacturer part warranties are passed through in full. If the same fault returns inside 12 months there is no second diagnostic fee.