LG Therma V Servicing & Repair
Annual servicing, fault-finding and repair for LG Therma V air source heat pumps — monobloc and split, older models and the newer R290 units — across Orpington, Bromley, Sevenoaks and Kent. £190 with no VAT.
LG Therma V Servicing
- £190 full annual service, no VAT
- £285 Therma V + cylinder together
- CH14 and other flow faults traced
- Pump, strainer & filter checked
- Any installer, warranty checked
What I Check on a Therma V
LG's Therma V is a capable heat pump, and when one misbehaves the cause is usually on the water side rather than inside the unit. That's good news, because water-side faults are normally cheaper to put right. Most of my Therma V visits come down to the same handful of checks.
Water flow through the unit
Therma V units watch the flow rate and stop with a flow fault when it drops below what they need. I measure what the system is actually delivering rather than assuming a running pump means enough flow. A heat pump short of flow works harder, cycles more and eventually locks out.
Strainer and magnetic filter
Heating circuits carry fine debris for years after installation, and it collects in the strainer and filter. A part-blocked strainer is one of the commonest causes of flow faults I find, so it is stripped and cleaned on every visit. Some LG documentation asks for a magnetic filter as well, so I check one is fitted and doing its job.
Pump capacity setting
LG's installation manuals warn against setting the circulating pump to minimum, yet I still find pumps turned down — often to keep things quiet on commissioning day. If yours has been, it goes back where LG intends and I explain why.
Pressure, expansion vessel and relief valve
System pressure checked cold and hot, the expansion vessel pre-charge checked, and the relief valve looked at for signs of weeping. A pressure that keeps falling means water is escaping somewhere, and every top-up adds fresh, oxygen-rich water to the system.
Controller settings and hot water
The heating curve, flow temperatures, hot water schedule and the disinfection cycle that heats the cylinder hotter to control legionella. Each is a running-cost decision as much as a technical one, so I go through changes with you rather than making them quietly.
LG Therma V CH14: The Flow Fault Explained
LG shows faults on the controller as CH followed by a number. The one I am asked about most is CH14, which means the unit is not seeing enough water flow. A restart may clear it for a while, but it comes back until the cause is fixed.
| Likely cause | What I check |
|---|---|
| Blocked strainer or filter | Strip and clean the strainer, check the magnetic filter and look at what has collected. |
| Air in the system | Vent the unit and the system; check automatic air vents are working. |
| A valve slow to open | Watch zone and diverter valves open and close — a slow valve starves the unit when the pump starts. |
| Pump capacity set too low | Compare the installer setting with LG's guidance. |
| Flow sensor or switch | Only once the water side is proven: the sensor, its wiring and its connection. |
Warranty, R290 and Your Records
Manufacturers generally expect an annual service by a competent engineer to keep warranty cover in place. I check your warranty paperwork before I start, record what I did and found in writing, and give you a copy for your file. Warranty claims go through LG or your original installer — I will tell you plainly if something looks like a warranty matter.
Newer Therma V monoblocs use R290 (propane) refrigerant. The refrigerant circuit in a monobloc is sealed at the factory, so routine servicing is on the water side, the controls and the electrics — the same as any other heat pump. If I ever suspect a fault inside the sealed circuit, I will say so and arrange the right route rather than open it up.
If the installer who fitted your Therma V has stopped answering, you are not stuck. I service and repair units whoever installed them.
Signs Your Therma V Needs Attention
The same CH code keeps coming back
A one-off code after a power cut is common. A code that returns every few days is pointing at something specific.
Radiators lukewarm while the unit runs
Usually flow rate, flow temperature or a heating curve set wrongly for the house.
Pressure creeping down
Water is leaving the system somewhere — the relief valve, a joint or the vessel — and wants tracing before it causes a lock-out.
Gurgling or a noisy pump
Air in the circuit. It also cuts flow, which brings you straight back to CH14.
Hot water slow to recover
A cylinder coil, a diverter valve not switching fully, or a setting.
Prices and What You Get
A full annual service of your Therma V is £190 with no VAT, with a written report. If you have an unvented cylinder, servicing both in one visit is £285 — £45 less than booking them separately.
Fault-finding visits are priced before I come out, and if a part is needed you get a fixed price before anything is ordered. Flow faults are often fixed on the day with nothing more than a clean strainer and a properly vented system.
I'm not VAT-registered, so the figure I give you is the whole price.
LG Therma V Questions
Book Your Therma V Service
£190 with no VAT, written report every visit, across Orpington, Bromley, Sevenoaks and Kent.
07717 846247
Other Heat Pumps I Service
Brand guides and the faults I see most.