Navien UK Avis 

Boiler had an electrical fault, identified on a Wednesday morning.

Called Navien support, who asked for the basic details of what seemed to be the issue. Was told i would be called back to arrange an engineer call out.

Called back to explain parts needed to be ordered, this is without even looking at the boiler just taking my explanation. Was told i would be called back.

I have called Navien 3 times a day since asking for an update. It is now the Tuesday after, and as of writing i am still awaiting an actual ETA.

The service team sounds helpful, but they actually provide little to no useful information and spend most of the call apologising.

In the mean time, not being able to go much longer without hot water and heat, especially with a 4 year old running riot, i called British gas who attended same day and prompty fixed the issue that required 2 new parts apparently from a phone dignosis.

Amazing what can happen when someone actually attends the issue.

Fitted an oil combi boiler. Really well packed supplied with most of the parts to start the installation. It was a boiler swap so a bit of pipework juggling! At first sight the setup instructions were a bit daunting but following them though step by step was surprisingly easy. Had to ask support at Navien about a couple of points not clear in the instructions but they responded within 24 hours. Boiler fired up first time very impressed

Grant turned up on time having previously contacted me with an eta. Work was done in a tidy fashion and I was kept informed as the job progressed. He tested the finished work very thoroughly and was courteous and informative throughout. I am extremely satisfied with the work done...

This is the first time I have written a review..never had such a good experience with a company..boiler stopped working on Tuesday phone navien only to be told boiler warranty wasn't received..no worries i will register it now..2 years after installation..Wednesday morning at 9 am engineer was at my door..15 hours from first call..had my boiler fixed... absolutely amazing service...if only every company was like that...amazing

Abysmal product (oil fired external LCB700) and service from Navien.
The first boiler we had installed burnt out, as it was installed incorrectly, and could have burnt our house down.
The replacement boiler (over 4 years old) has never worked properly. It's had circa 10 different fault codes and around 20-30 breakdowns.
It is a painful and time consuming process to get someone out to repair it. We've had engineers apparently booked and they never turn up. Each time it breaks down we're left without heating and hot water for over a week. When repairs are made they're often not correct, and require follow up.
A lot of the time they try and pass the blame on to us (their APPROVED engineer installed it?). We've spent thousands on rectifying apparent issues, including new oil tank and oil line, which made no difference to the barrage of fault codes.
The 10 year warranty is completely meaningless. We've only used Navien approved installer to service the boiler. Every single one has completed the service incorrectly, including leaving parts out of the boiler. causing it to breakdown. Their Navien 'in house' engineer promised they would complete the servicing going forward, as they recognised it was not feasible to use their approved installers. I'm now being ignored by their engineer. We're left in an impossible situation. Navien doesn't have one approved engineer in the whole of Surrey. Ironically, Navien are located in Guildford, only 25 minutes from us, and still they won't help us.
The boiler has just broken down again (Sunday 19th April). Promised an engineer today, 21st April. Navien just called to say the engineer is sick and now won't come to Thursday. I reiterated we had a baby and small child, with no heating or hot water.
13th April 2026 I emailed Navien to lodge a formal complaint. I've not received any acknowledgement. I am leaving this review as a last resort, as I like to provide opportunity for companies to set things right.
Navien - your product is unfit for purpose and I will be progressing the matter in the Small Claims Court unless you contact me to resolve this.

22/04/2026 Response to Ellice -
Ellice, I have already emailed, using the email address supplied in your reply to my review, first on 13th April and then again on 20th April to chase up a response. You've not responded to either?

Rhys came out to fix an issue with boiler. He was professional, polite, tidy and explained everything in simple terms I could understand.

1 star — Avoid. AT ALL COSTS .Would give a minus star if I could.

Unreliable boiler and no resolution after over a year.

I have spent over £3,000 trying to get my Navien oil boiler to work properly since installation. Within the first year it was already suffering repeated flame loss and lockouts requiring constant resetting.
In an attempt to resolve the issue I have had a new oil line fitted, a tiger loop installed, and an oil lifter fitted — all at my own expense — on the assumption the problem was the system rather than the boiler itself. It still cuts out.
Despite using a Navien recommended contractor, the fault has never been properly diagnosed or resolved. The boiler has been unreliable since December at the latest, requiring regular manual resets just to maintain basic heating and hot water.
The consequence of this ongoing failure is that my tenants are now withholding rent, leaving me significantly out of pocket on top of the repair costs already incurred.
I would strongly advise anyone considering a Navien oil boiler to think carefully before purchasing. When things go wrong the support and resolution process is wholly inadequate.

And thank you to Navian for your feedback below. I can confirm that I reached out to them using the email below. But no response yet…… I will update this review as and when I hear from them!

A 90-year old with no heating - phoned Navien for help and was put through to Aubrey. What a splendid chap! He courteously, patiently and efficiently guided me to a resolution of the problem. I could not have been more satisfied with the service he provided.

From my initial phone call to Navien about my boiler fault, the repair was carried out within 24 hours and the engineer was very efficient and courteous. Everything was tested thoroughly before he finished and left clean and tidy.

Our boiler has been a bit tricky however Navien sent an engineer up the next day with all the parts to get it working again :-)

Very well presented, very friendly making me feel at ease and did a wonder job getting my boiler working again. Didn’t take him long to work out what the problem was and he got straight to work and I have heat again. No mess was made. Highly recommend

Navien are inefficient, and don’t care about their customers. They are leaving me without hot water and heating for 10 days. They cut you off when you speak to them, wouldn’t have another Navien boiler under any circumstances

An update- after 4 days a Navien Engineer came and fixed the boiler. Many thanks Navien. Now a week later, fingers crossed, it’s still producing hot water and heating. Thanks again.

Had a Navien boiler for about 3 yrs, warranty is for 10 yrs, experienced loss of pressure over and over again just randomly, tried on multiple times to log a support request with Navien via the web site, nothing heard back, really poor I thought.
Booked a British Gas engineer to come out, they sorted it the next day, had to change a pressure relief valve and complained that Navien were bad for spare parts, lesson learned, cost me a couple of hundred quid to fix but I was desperate...no more Navien for me after this, take note if you are reading this, after sales is important and Navien are particularly bad at it

Have gone from 1 star to 5.
Faulty boiler but at the end of the day, customer services did what they committed to, found an engineer who came out and fixed it n day.

Thank you

We got our boiler fitted by Boxt.Navien boiler.Pressure dropping after a year.We had it serviced.Phoned for engineers to come out which was about half an hour.The date n 8-1 time slot with an hour's notice phone call.No phone call! Just a message saying he was here at 12.20 looked at cameras it was 11.30.Had to phone again n they said will sort same day but 1-6 after changing my day around.Assured me i would get a phone call.If they phone n I get my boiler sorted by this company Navien I will be back on Trust pilot with a gleaming report n a 5 * but something tells me....I won't hold my breath!! The engineers came out still no phone call from Navien.The British Gas engineers-really good n hopefully sorted it now.Navien boiler is good.Boxt who fitted it are good.British Gas are excellent.So the most simplest but worst is Navien customer service!! Sort this out-its ridiculous.How difficult is it to phone a person to give 1 hours notice?! Obviously difficult....its not rocket science.Navien please sort this out!! The day after had to do pressure x 3 times phoned Navien n waiting for a phone call.Hppefully won't have to have British Gas out every week.Also contacted Boxt no reply yet

Navien UK Team always going above and beyond the call of duty - you are not only buying a great product but also peace of mind for many years to come. One of the best Customer Service Teams I have ever dealt with - well done and keep it up. Chris / Ayrshire

The Boiler broke down yet again. After phoning the helpline and being transferred to the Philippines. I was put on hold for only 43 minutes to be told someone will call me back. Luckily this time they did and was given an appointment for Thursday and told the engineer will call me one hour before arrival. This must have been lost in translation and the British Gas engineer called to say he was ten minutes away, not great as I was twenty minutes away. One very unhappy engineer who said he would come back later, 3 hours later only to tell me he didn’t know anything about the Navian boiler( great convenience boost for me) turns out he didn’t know about it as he came back Friday to try again. I called the customer service line and was told to call back Saturday morning. Called Saturday morning to be informed that a Navian engineer would visit and I would get a call within the hour. Fare enough he didn’t say what day that would be. Monday got the call to say the engineer would be there on Friday. Yes that is two weeks without heating and hot water. Good news is the coldest February. Great service NOT. A compete shambles

I originally experienced a very frustrating issue with my Navien oil combi boiler, which is only four years old and covered by a 10-year warranty. After reporting a fault on 29/12/2025, we unfortunately experienced periods without heating and hot water, which was particularly difficult with an infant in the household. There were delays with parts and communication, which caused understandable concern at the time.

However, I am pleased to say that the situation was resolved in a way that truly deserves recognition.

On 06/02/2026, Chris Peden, the National Service Manager for Navien UK and Ireland, personally attended our property to resolve the issue. Chris travelled over 12 hours round trip to ensure the fault was fully diagnosed and repaired, which demonstrates an exceptional level of commitment to customer service.

Chris was extremely knowledgeable, professional, polite, and thorough throughout the visit. He took the time to explain the issue, ensured the system was fully operational before leaving, and even provided his direct contact details for any future concerns. His dedication and willingness to go above and beyond completely restored our confidence in Navien as a company.

While it is unfortunate that it required escalation to reach this point, the level of care and ownership shown by Chris reflects very positively on Navien’s commitment to standing behind their products and supporting their customers.

Thank you again to Chris and Navien for resolving the issue and ensuring our home is warm and fully functioning again.

— A very appreciative customer

Had a visit from an engineer today who supposedly made a temporary repair, of which the boiler is still not working.
Thus saying a service is needed to get the boiler working
My own engineer cannot visit until 21st as very busy, which is understandable being the winter.
Now we will be without hot water and heating for 18 days
Call navien warranty useful... I think not!
Very unacceptable

I am writing to formally recognize the outstanding support I received from Matthew Cundill regarding the heating system at our property located in Snowdonia National Park.

Because our property is a five-hour drive from our primary residence in London, remote reliability is absolutely critical for us.

We recently experienced a total loss of communication with the boiler management system. Upon arrival, we discovered the batteries in the Smart Plus NCR10-RW Wireless Room Thermostat had been exhausted, and the radiators were failing to reach the necessary temperatures for the local climate.

Matthew provided expert guidance that went above and beyond a standard service call. Specifically:
• Permanent Power Solution: Matthew helped me find a battery replacement/power adapter solution that connects directly to the wall plug. This ensures we will never again lose communication due to battery failure of the Smart Plus NCR10-RW Wireless Room Thermostat —a vital fix for a remote property.
• Climate Optimization: He guided me through recalibrating the Weather Compensation Factor Curve specifically for our geolocation. This ensures the boiler now responds correctly to the extreme cold of North Wales.

In an era where remote management is essential, Matthew’s technical knowledge saved us from a potential disaster, including the risk of frozen or burst pipes. He is a credit to the Navien team, and his expertise has given us immense peace of mind.