Navien boiler repair and service engineers in London
Made by a Korean company, with a current UK gas range best known for strong hot water flow.
- Fully insured and Gas Safe registered
- Every fault diagnosed before we quote
- You agree the price before we start
- Our workmanship is guaranteed
Monday – Sunday, 7:00 AM – 10:00 PM · Out-of-hours emergency? Call 020 3576 5825
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Navien boilers
Navien’s reputation rests on combis with unusually high hot water flow. That makes one a sensible pick for a home that wants the simplicity of a combi but uses more hot water than an average combi can supply. The company makes oil boilers as well, but Ninja Plumbers works on the gas range only.
The Navien range
Navien belongs to KD Navien, a South Korean heating company that is a major name at home and in North America, and it reached the UK later than most of the brands we cover. Its UK gas range is built around combis designed for more hot water flow than usual, for homes that want a combi but have more than one bathroom. A high-flow combi can only deliver what the incoming mains gives it, and in parts of London the mains is the limit.
Faults we often find on Navien boilers
- High-output combis chosen for homes that use a lot of hot water
- Faults in controls and sensors more than mechanical wear
- Installations where the boiler was picked for its flow rate
- Mains supply that cannot keep up with the flow the boiler can give
- Scale on the hot water side, which affects a high-flow combi sooner
This list reflects what Ninja Plumbers finds across Navien boilers in general. It is not a diagnosis of yours, and we confirm any fault on site before giving a price.
Navien servicing
Navien’s warranty usually asks for the boiler to be registered and serviced every year — check your warranty terms for the details. A high-flow combi moves more water through its heat exchanger than most, so in hard-water London the scale reducer on the incoming mains deserves a look at every service. If the boiler is not giving the flow it should, the service is a good time to measure the incoming mains, because the cause may be outside the boiler.
Repair it or replace it?
Most Navien installations in London are fairly recent, so check the warranty first, and expect repair to be the answer. Faults tend to be sensors and controls rather than wear. Parts may need ordering, which can mean a wait. On an older unit with a major failure outside warranty, ask whether you still need a high-flow combi before replacing like for like.
Work we do on Navien boilers
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Navien boiler repair
We find the fault first, then quote for the fix.
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Navien boiler service
An annual check, which most manufacturer warranties require.
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Navien boiler installation
Matched to your home, at a price agreed up front.
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Navien boiler replacement
You see repair and replacement costs side by side first.
Questions about Navien boilers
- Will a Navien combi really supply two showers?
- Its higher-output models give far more flow than an ordinary combi, but the true answer depends as much on your incoming mains as on the boiler. No combi can deliver flow the mains does not supply. We measure your incoming supply before recommending one.
- Is a high-flow combi dearer to run?
- Not by itself. A combi only burns gas while it heats water or radiators, so running costs depend on how much hot water you use, not on the most the boiler could deliver.
- Is Navien a new make?
- Newer to the UK, not new. Navien has made heating products in Korea for decades and is used widely in North America. There are fewer in the UK, so parts are sometimes ordered in.
- Can you repair and service my Navien boiler?
- Yes. Our gas work is done by Gas Safe registered engineers, as the law requires for any gas boiler, whatever the make.
We handle every make of boiler
Problem with your Navien?
Tell us the model and whatever fault code the display shows. We can often say what the likely problem is before an engineer is on the way.