Navien UK Avis 

Engineer called 1/2 Hour before arrival to say he was on his way.
Engineer was polite and courteous and fixed the problem in 30 minutes and explained what to do if I have any further problems.
Brilliant!

RHYS come to our property yesterday and fixed our boiler. He was very helpful, explained the problem and made recommendations to improve the efficiency of the boiler. Excellent service and support provided as I only contacted the company in the morning and they had a booking secured 30 minutes later for later that same day. Would recommend RHYS and Navien.

Left without a functioning boiler and no way of getting help! Stay clear of this type of boiler! We had a whole new central heating system in 2022. Pro Plumb (Navien's number 1 Installer) fitted it for us. Since then it has broken down four or five times. We have discovered you need specialist engineer to service and repair it - they are hard to find. We currently have two leaking valves that need replacing inside the boiler. Navien say it is because they have been installed upside down so will not repair, ProPlumb will not respond to our calls, we can not find anybody who is willing to touch this system. Consequence, we are now on week three of no hot water with nowhere to go. Back to the Victorian times with a small child living in the house. I feel like crying!

Contacted me quickly when called. Convenient appointment made. Engineer kept in touch & turned up in time. Repair completed & everything tidied & clean. Very efficient.

I didnt have no hot water, spoke to someone called albury he guided me through step by step instructions to put pressure up in my boiler, should a great help and very patient and knowledgeable

Great service unlike British Gas who where trying to find ways out of doing actual job ,,

Navien LCB 700 Oil boiler .
First class service once again from phoning Navien to booking a call-out to Engineer attending.
Engineer very knowledgeable and it would appear issue sorted.
Thanks

My thermostat needed fixing yesterday and just wanted to say that I was put through to the technical team. I cannot praise enough a man named AUBREY he was so patient in going through setting it right for me, I botched it up by dropping it at one stage but he was so calm and helpful, he deserves a mention.

Super quick- spoke with Aubrey over the phone - he was able to talk me through sorting out onev of the issues and go my boiler back on again. Then sorted someone to come look at the leak.wad very patient with me, lovely bloke, easy company to deal with.

Great after sales service for my LCB 700 combi boiler. The engineer Rhys carried out a thorough service of my boiler and obviously knows his stuff.

The man that came out to sort the boiler was lovely, ive just lost my husband and he was very caring and put me at ease straight away.When he had completed the job he gave me time to write down what I needed to know to pass on to my son.
I would definitely recommend this firm.
Thanks again the customer service was fantastic.

An engineer called Rhys came out to fix a sensor problem on the boiler today. Fast and friendly service.

The water heating is very good but the heating is quite a different matter. The screen on the remote controller for heating suddenly went blank and the heating is now constantly on so I have to control it by turning on/off at each radiator although I have to leave one running constantly to avoid a constant clanking and banging noise.I’ve tried on many occasions to reset the controller but to no avail. When I contacted the installer I was told that a visit would cost £120 + VAT. I declined this and decided that it would be better to put that money towards my next oil delivery.

Bit of a mixup in arranging the engineers visit but all good in the end.

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.