Main boilers
Main Heating is a sister brand of Baxi. Both belong to the same group, along with Potterton. Baxi describes Main as high-efficiency boilers sold only through independent merchants.
Main boilers today
Main’s own website still exists, but its boiler pages now take you to Baxi. The current boilers carry both names: Baxi MainEco Compact. There are three types:
- the MainEco Compact Combi, for heating and hot water from one box;
- the MainEco Compact System, for homes with a hot water cylinder;
- the MainEco Compact Heat, for homes with a cylinder and tanks in the loft.
Older boilers may just say Main Eco Compact. They’re the same family. Check the label on the front, or under the boiler, for the full name.
Fault codes on a Main boiler
Main boilers use Baxi’s style of fault codes: an E and a number, such as E118. Baxi’s technical list puts the Main Eco Compact Combi and System alongside its own boilers. So Baxi’s codes apply to them too.
The two codes most homeowners see are in the table on this page. E118 means low pressure. That’s one you can usually fix yourself. E133 means the boiler couldn’t light. In winter, a frozen condensate pipe is a common cause.
Watch out for a common mix-up. Many websites say E119 means low pressure on these boilers. Baxi’s own list says E118. Our Baxi page explains more, and lists other Baxi codes.
Help and manuals
Because Main is part of Baxi, you get help through Baxi. Baxi keeps the user guides for its boilers in one place, and you can register your warranty there too. Baxi’s warranty sign-up covers the Main Heating brand.
If you can’t find your exact Main model, contact Baxi with the model name and GC number. Our guide shows how to find your boiler’s model and GC number.
Before you call an engineer
- Check the pressure gauge. If it’s low, see how to top up low boiler pressure.
- Make sure your other gas appliances work, such as the hob.
- If you have a prepayment meter, check there’s credit on it.
- In freezing weather, look at the condensate pipe outside. See how to thaw a frozen condensate pipe.
If none of that helps, call a Gas Safe engineer. Tell them it’s a Main boiler, and give them the code.
Main gas boiler ranges
These are the gas boiler ranges on the Main website as of 21/10/2026.
- Baxi MainEco Compact Combi Combi
- Baxi MainEco Compact System System
- Baxi MainEco Compact Heat Regular
Older Main ranges
You may still find these in homes. They are no longer sold new, but many are still working.
- Main Eco Compact Combi and System
Common Main fault codes
Codes can differ between models and ages of boiler. Always check the user manual for your exact model.
| Code | What it means | What you can do |
|---|---|---|
E118 | The water pressure is low (under 0.5 bar). | Top up the pressure with the filling loop, following your user guide. |
E133 | Gas supply fault. The boiler couldn't light. | Check your other gas appliances and any prepayment meter. In cold weather, check the condensate pipe for ice. |
Main manuals
Main puts its user guides and installation manuals on its own website. You can find Main manuals here. You'll need your model name. The GC number helps too. Our guide shows you how to find your boiler's model and GC number.
Stay safe. You can reset a boiler, top up its pressure and thaw a frozen condensate pipe yourself. Anything inside the case is a job for a Gas Safe registered engineer.
If you smell gas, leave the building and call 0800 111 999.