Boiler losing pressure in Edinburgh — traced and fixed
Topping the boiler up every week is not normal. In Edinburgh's tall tenements the static head punishes a tired expansion vessel faster than anywhere else — we trace the actual cause instead of selling you a top-up loop.
Boiler losing pressure in Edinburgh — traced and fixed?
A boiler that keeps losing pressure has one of three causes: a discharged or failed expansion vessel, a weeping pressure-relief valve, or a leak on the system. In four and five-storey Edinburgh tenements the expansion vessel is the culprit far more often than in houses, because the static head is higher. A £95 diagnostic includes a pressure-drop test that separates the three.
Key points
Expansion vessel lost its nitrogen charge — recharge or replace
Pressure-relief valve weeping to the outside discharge pipe
Pinhole leak on buried pipework or under floorboards
Failed auto air vent dripping inside the boiler casing
Most likely causes
Expansion vessel lost its nitrogen charge — recharge or replace
Pressure-relief valve weeping to the outside discharge pipe
Pinhole leak on buried pipework or under floorboards
Failed auto air vent dripping inside the boiler casing
Radiator valve gland or towel-rail joint weeping slowly
Check these before you call
Look for a drip from the small copper discharge pipe outside — that is the PRV
Check under the boiler and around radiator valves for staining
Note how fast it drops: hours means a leak, weeks usually means the vessel
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
Once or twice a year at most. Weekly or monthly topping-up means an active fault, and repeatedly re-pressurising introduces fresh oxygenated water that corrodes radiators from the inside.
Why is this worse in my top-floor tenement flat?
A fifth-floor flat can have 12–15 metres of static head above the boiler. That extra pressure exposes a weak expansion vessel or a tired PRV far sooner than the same boiler in a bungalow.
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.