Boiler Installation FAQ’s

Boiler Installation FAQ’s Matty September 7, 2022

Boiler Installation

Boilers more often than not bought online. You can trust the survey and the delivery you’ll receive from WarmZilla. 

Complete our online survey and we’ll recommend suitable products for you.

Select the product that does it for you. Use our comparison tool to make it easier.

Select a date that suits you on our installation calendar, some days even have additional discounts on them from time to time. 


WarmZilla’s boiler installation area includes the mainland UK and some surrounding islands. We currently do not cover Northern Ireland.


We have a network of 500+ fully qualified Gas Safe engineers covering all corners of the UK making us your local national company. 

To fit new boilers for WarmZilla, every engineer has to go through a vigorous vetting process that checks their background, technical ability, and certifications. If they don’t meet our standards, they aren’t allowed in. We consistently monitor the progress of each engineer and provide constant training. 

Typically a combi to combi, standard to standard and a system to system swap takes up to 1 full day. A conversion from a standard boiler to a combi can take up to 2. In the event of unforeseen circumstances, these may be slightly longer. An electrician may be required in some rare circumstances. 

Our engineer will arrive with your boiler and all the necessary parts. They usually arrive between 8-11am but they will call to let you know when they will arrive.

Our Gas Safe engineers will carry out the work to the highest possible level, making sure they protect any areas in which they work and cleaning up any areas in which they have worked.

We only ask that you clear the areas in which the engineers need to work to give them access. Apart from this? No, just put the kettle on.

Your new boiler and associated parts will be brought to your home address on the morning of installation with your engineer. Sometimes, we will have the pack delivered with delivery times between 7-10:30 am. 

Yes, your engineer will fully protect your home before the installation commences with dust sheets. If you require additional protection for any part of your home, please ask your engineer.

Yes, your engineer will contact you before their arrival on the day of installation. 

Yes, all boilers we install are registered with Gas Safe. This is completed once we register your boiler with the manufacturer. All your installation documents can be found within your Home Hub after installations. 

Yes, it’s you the customers responsibility to ensure parking is available for the engineer on installation day. This applies to parking permits and any costs attributed to it. 

WarmZilla is open at the following times:

Live Chat:

Monday to Friday: 8 am – 5 pm
Saturday: 9 am – 1 pm
Sunday: Closed

OUR 24 HOUR AUTOMATED HELPLINE: Freephone 0333 577 9090

Outside of opening hours please email or an Enquiry Form on our Contact Us page, and we will get back to you as soon as possible. Thank you.

We often get asked what is the best boiler to buy. There are a few factors that affect which boiler might best suit your home. 

We’ve created a Best Boiler Brands blog that breaks down the best budget and premium boilers in the combi, system, and regular boiler categories.

Yes, it will. The only reason it would not be removed from your home is if the builders opening has been fitted too tightly around the back boiler. 

All associated pipework will be decommissioned and/or reconnected where required.

It’s 50/50. Low-pressure showers cannot usually take the new high pressure entering them and may leak internally. It’s best you check this with the manufacturer of the shower to see if possible. In the case that it is not compatible a new high-pressure shower is required. This is not part of the fixed quote. 

Probably not if this is a conversion from a standard boiler to a combi. However, you will have cold water and in most scenarios, your gas back up and running. It’s always best to stipulate your requirements with the engineer before the installation takes place. 

Our survey covers all we require to advise you on our boiler packages. We will ask for photos once you have purchased, just to hand over to our engineers and/or for us to check. This is to ensure a smooth process. 


If you would like to send us pictures before installation then please to and we will be happy to help.

Yes, we wire your existing or new thermostat up to the new boiler. We do not wire up or supply 2 zone systems. A 2 zone system is where you have control of your heating downstairs and upstairs, independently for example. 

Please read our T and C’s for further clarification on electrical work. 

Yes, all of our engineers or ‘WarmInstallers’ as they are called are all Gas Safe registered as a minimum requirement.

It covers all boiler breakdowns for the warranty period specified by the manufacturer. It covers parts and labour providing you meet the manufacturer’s requirements on the guarantee – this usually requires you to get your boiler serviced annually by a Gas Safe engineer.

**Special Offer packages provide a 12-year guarantee/warranty. 10 year manufacturer and 2 years exclusive from WarmZilla** T and C’s apply. 

If you do not have a hot water cylinder and tanks in your attic then it is likely you have a combi boiler. If you do have a hot water cylinder and tanks in the attic, then it is likely you have a standard or back boiler unit. If you just have a hot water cylinder and no tanks in the attic it is likely you have a system boiler.

You can read more about the different boiler types in our blog article.

It really depends on the cost of the boiler repair – they can be quite costly and in a lot of cases will only be a matter of time until another boiler repair is needed.

Our new boilers come with a minimum 5-year manufacturers guarantee, so any future boiler repair is free of charge. Modern-day combi boilers are also a lot more efficient which can save you up to £360 per year on your central heating bills.

You can read our blog article should I repair or replace my boiler for more information.

You will need to call the boiler manufacturer and book a breakdown service call. All phone numbers will be located in the installation booklets left at the time of your boiler installation or you can use the below as a guide. 


If your boiler is made by Worcester Bosch call 0330 123 9559

Open Monday to Friday 7am to 8pm, Saturday 8am to 5pm, Sunday 9am to 12pm. Opening times may vary and are at the discretion of the manufacturer. 


If your boiler is made by Ideal call 01482 498660

Open Monday to Friday 8am to 6pm, Saturday to Sunday 8.30am to 2pm, Bank Holidays (including Christmas and New Year) 8.30am to 2pm. Opening times may vary at the discretion of the manufacturer. 


If your boiler is made by Vokèra call 01274 866 100

Open Monday to Friday 8.15am to 5pm, Saturday 8am to 12pm. Opening times may vary at the discretion of the manufacturer. 


If your boiler is made by Vaillant call 0330 100 3143

Open Monday to Friday 8am to 6pm, Saturday 8am to 3pm and 8am -12pm Sunday. Opening times may vary at the discretion of the manufacturer. 


If your boiler is made by Viessmann call  01952 675000

Open Monday to Friday 8.30am to 5pm, Saturday 8am to 1pm. Opening times may vary at the discretion of the manufacturer. 


If your boiler is made by Atag call  0800 680 0100

Open Monday to Friday 9am to 5pm, Saturday 8am to 12pm. Opening times may vary at the discretion of the manufacturer. 

It’s important to service your boiler annually, not just to maintain your boiler manufacturer’s guarantee/warranty but to ensure your own safety.

To service your boiler you can use any gas safe engineer or we can service the boiler for you. If you would like a boiler service please use this link 

**Special Offer packages provide a 12 year guarantee/warranty. 10 year manufacturer and 2 years exclusive from WarmZilla** T and C’s apply.