FAQs
Our Frequently asked questions can be found here. Please use the category filters to the left and questions within those categories on the right. Hopefully, these will help you find the answers you are looking for. If not please use the contact us page and we will try to help.
Browse Categories
All FAQs
How do I view my account and Navien Choice in the Navien Warranty app?
How do I register and sign up to the Navien Warranty App?
How do I register a new boiler installation on the Navien Warranty App
What do the codes and symbols mean on the front of the LCB700 boiler?
What do the codes and symbols mean on the front of the NCB300?
What do the codes and symbols mean on the front of the NCB500 and NCB700?
What do the codes and symbols mean on the front of the NCB-CE Gas Boiler?
What is Boiler Plus?
From 6 April 2018, when a new boiler is installed in England, there are additional measures that must now be met. This is a new piece of legislation called ‘Boiler Plus’
Boiler Plus has been introduced by the government department BEIS (the Department of Business, Energy and Industrial Strategy) and aims to reduce domestic carbon emissions and encourage energy efficiency. Gas-fired heating contributes about 60% of what is spent in a year on energy bills, this new legislation should, therefore, save you money. The requirements are flexible to allow a suitable choice to be made.
1. Any Gas boiler installed or replaced in existing dwellings in England must be of a minimum 92% efficiency (minimum performance standard) under the European rating system (ERP) which aims to phase out poorly performing products.
2. In addition, all new gas and oil boiler installations must include ‘boiler interlock, time and temperature controls’ (programmable timer and a thermostat)
3. Gas combination boilers must also include at least one of the following energy-saving options (see next page for explanation) :
• Flue Gas Heat Recovery (FGHR)
• Weather compensation
• Load compensation
• Smart thermostat with automation and optimisation
These changes are not optional as they form part of the building regulations in England which must be adhered to by law. Your Gas Safe or suitable competent persons scheme member registered installer can discuss with you the options suitable for your needs.
My system comes on during the night or in cold weather when not asked for?
Check the minimum room temperature setting on your Smart Plus controller; this should be a low-temperature setting e.g. 8°C to 12°C. If the minimum setting is too high e.g. 18°C, then when the room temperature falls below 18°C during an off period, then the room stat will bring on the boiler and keep the house up to 18°C when the house should be allowed to fall to a much lower temperature whilst no heat is required.
Do Navien boilers have a pump over-run?
When the boiler is not required to heat the system anymore, the pump will continue to run after the burner has gone out, so heat can be dissipated around the system.
(Note: Regular boiler only. The pump must be wired into the pump connections on the boiler)
Do Navien boilers have a built-in frost protection?
Navien boilers incorporate a built-in frost thermostat which automatically turns on the boiler and pump if the water in the boiler falls below 10°C, providing the electrical supply is on. The boiler will operate until the water temperature in the system reaches approximately 10°C measured on the flow sensor in the boiler.
Any other pipework outside of the boiler should be protected from the risk of freezing and protected with suitable insulation. Additional protection from external frost thermostats and pipe thermostats should also be considered.
For systems requiring freeze protection, use only inhibited propylene glycol, specially formulated for hydronic heating systems; use of other types of antifreeze may be harmful to the system and will void the warranty.
Can 87-degree bends be used on vertical flue systems?
Yes, on our condensing boilers, you can fit 90-degree bends onto a vertical flue system. Note: An 87° bend is equivalent to 1.3m length of flue. If it is necessary to use an 87° bend in the vertical flue, ensure any horizontal flue lengths are sloped towards the boiler to ensure that all condensate is allowed to drain from the flue. The slope must be a minimum of 25 – 30mm per meter.
What is the maximum equivalent length of a boiler’s flue?
The maximum horizontal equivalent flue lengths (after the first elbow) is: 20m
The maximum vertical equivalent flue lengths is: 21m
Allow 1.3 meters of flue length for each 87° bend
1.0 meters of flue length for each 45° bend.
| Maximum horizontal equivalent flue lengths (m) | Maximum vertical equivalent flue lengths (m) | 87° Elbow (m) | 45° Elbow (m) | |
| NCB-CE | 20 | 21 | 1.3 | 1.0 |
| NCB300 | 7 | 8 | 1.3 | 1.0 |
| NCB500 | 7 | 8 | 1.3 | 1.0 |
| NCB700 | 20 | 21 | 1.3 | 1.0 |
| LCB700 | 20 | 21 | 1.3 | 1.0 |
| NPE A/S | 20 | 21 | 2.4 | 1.2 |
Note: The maximum horizontal equivalent flue length is measured after the first elbow.
What does the fault code E302 mean for the LCB700?
This means that the system pressure is too low and you may see that the system pressure gauge or the pressure reading on the front display indicates that the pressure in the system is below the 1 bar pressure.
To re-pressurise the system you will find a filling loop (metal braided flexible hose) on a combi boiler version near the top right of the boiler with two tap connections at either end of the filling loop. Two small black tap handles.
The taps should be opened a quarter of a turn. Open one small black tap one and then open slowly the other small black one. The water will start to refill the system (water should be heard filling the system). You should see the pressure gauge or the reading on the front display rise back up between 1 bar and 1.2 bar pressure and then stop filling.
Once the pressure gauge is between 1 bar and 1.2 bar turn the taps back to the off position and the water will stop filling the system. The error code E302 will stop and the boiler will now operate. If the error code E302 is still active, fill up the system a little more but not over 1.5 bar.
(If you do fill the system too much and the pressure gauge is too high, just bleed water from a radiator until the pressure on the gauge goes down to below 1.2 bar).
What does the fault code E302 for NCB500 or NCB700 mean?
E302 means that the system pressure is too low and you may see that the system pressure gauge or on the front display indicates that the pressure in the system is below the 1 bar pressure.
To re-pressurise the system, you will find a NaviFill Link (a plastic and brass link with a green plastic leaver) on the underside of the boiler.
The green leaver needs to be pulled down slowly. The water will start to refill the system (water should be heard filling the system). You should see the pressure gauge or the pressure reading on the display rise back up between 1 bar and 1.2 bar pressure and then stop filling.
Once the pressure gauge or pressure reading on the display is between 1 bar and 1.2 bar release the green leaver and the water will stop filling the system. The error code E302 will stop and the boiler will now operate. If the error code E302 is still active, fill up the system a little more but not over 1.5 bar.
(If you do fill the system too much and the pressure gauge is too high, just bleed water from a radiator until the pressure on the gauge goes down to below 1.2 bar).
How can consumers save money with Navien boilers?
Thanks to a range of features within Navien’s boilers, there are a host of savings on offer. For example, the NCB700 ON boiler saves 7,787 litres of water and 38% gas on average per year – equating to a saving of around £513.
How energy efficient are Navien boilers?
All Navien products deliver the highest levels of energy efficiency. When used in conjunction with Navien’s Smart Plus controls, they can achieve ErP A+ (98%) efficiency ratings. The NCB700 ON gas boiler requires just one Smart Plus to achieve this, whereas NCB500 ON, NCB300, NCB-CE gas models and LCB700 Blue Flame oil boilers need to be fitted with three Smart Plus thermostats respectively.
Further details can be found in our product brochures.
What is energy efficiency?
Boiler efficiency is determined by how much fuel (e.g. gas or oil) it can turn into usable energy compared to how much is wasted in the process. So, a boiler with a 94% efficiency rating would only waste 6% of the fuel it uses, so is deemed to be highly efficient. Every boiler also has an ErP (Energy Related Products Directive) efficiency rating which indicates how efficiently each unit will perform.
Can I run a shower from my combination boiler?
Yes, you can run a shower from your Navien combi boiler. Dependent on the model and size of your boiler you could up to 3 showers at a time with a gas model and 2 showers with an oil model.
Can I use 3rd party controls on my boiler?
Yes, you can use 3rd party controls with our boilers. They do need to be volt free as our wiring interface is potentially free. Also Navien NCB comes “OpenTherm” ready this will give instant access to the latest control technology with minimum disruption and less cost on installation.
What type of boiler do I need
Our Find a Boiler tool takes into consideration your property type, size as well as the number of bedrooms and bathrooms to see whether you need a combi, system or regular boiler.
What size boiler do I need?
This is determined by the number of bedrooms and bathrooms. Simply find a suitable size of boiler for your house by using our Find a Boiler feature
Do you recommend system cleaning before installation?
We recommend that the system is flushed thoroughly before installation and a good quality magnetic filter. Our boiler also has particulate filtration built in.
What warranties do you offer?
Navien undertakes to rectify any manufacturing defect that occurs within the warranty period after the installation date. Each model has a different warranty period. Navien Warranty registration is simple. Just take a picture of your Warranty Registration Card or Benchmark Commissioning Checklist, and email to [email protected]. The details of installation will then be automatically registered within Navien Service Management System. Alternatively, please telephone one of our Warranty Registration Advisors on 0344 332 2323.
Warranties can be checked and downloaded from the warranty look up page.
What maintenance will my boiler need?
We require that the unit is serviced yearly by a competent engineer. Failure to do this will invalidate your warranty.
What does my warranty cover?
Your product will be covered for breakdown due to failure of components within the boiler. If however, the failure is due to poor installation or sludge in the system this may not be honoured at our discretion.
Warranties can be checked and downloaded from the warranty look up page.
Where can I buy a Navien product
Navien products are available from over 400 merchants nationally, For more information please email us at [email protected].
What does the fault code E302 for NCB-CE or NCB300 mean?
E302 means that the system pressure is too low and you may see that the system pressure gauge indicates that the pressure in the system is below the 1 bar pressure.
To re-pressurise the system you will find a filling loop (metal braided flexible hose) on the underside of the boiler with two tap connections at either end of the filling loop. One small blue & one small black tap handles.
The taps should be opened a quarter of a turn. Open the small black one and then open slowly the small blue one. The water will start to refill the system (water should be heard filling the system). You should see the pressure gauge rise back up between 1 bar and 1.2 bar pressure and then stop filling.
Once the pressure gauge is between 1 bar and 1.2 bar turn the taps back to the off position and the water will stop filling the system. The error code E302 will stop and the boiler will now operate. If the error code E302 is still active, fill up the system a little more but not over 1.5 bar.
(If you do fill the system too much and the pressure gauge is too high, just bleed water from a radiator until the pressure on the gauge goes down to below 1.2 bar).
How can we help you?
What Boiler do I Need?
Find a Boiler
Find an Installer
Find an installer
