home pageunvented cylindersPlumbingHeatingPower Flushing

Advice PageElectricalPhoto PageCarbon MonoxideLinks Page

BPECCity & GuildsW.R.A.SPart P Electricalgas safe register


Winter advice
(from the Baxi web site)

Everyone will have noticed the harsh weather conditions that are currently gripping the country, and everything has been affected. Even our boilers. We’ve noticed that the low temperatures have caused some of the external pipework connected to our high efficiency (HE) boilers to freeze.

This will be apparent if your boiler is displaying the code E133 on its display panel. The display will alternate between E1 and 33.

We hope that the following easy steps will help to get your boiler working again without the need for an engineer’s visit.

- If the boiler is displaying error code E133, check to see if the condensate pipe is located outside, as it may be frozen. It is a plastic pipe that leads into the drainage
- To unfreeze the pipe, the best solution is to pour hot, but not boiling, water across the length of the plastic pipe until it has defrosted. This could take around 30 minutes, but the boiler will not light until this pipe has cleared
- Once the pipe has thawed out, the boiler needs to be reset, and then should fire up and run as normal

The E133 error code will appear on all Baxi Platinum, Duo-tec and Megaflo boilers.


Q. I’ve tried the above and the boiler is still displaying the error code
A. Don’t worry, give us a call and we can send one of our engineers out

Q. What if I don’t feel comfortable doing this?
If you don’t feel comfortable contact your installer or give us a call, however there may be a charge for this.



What is a condensing boiler

Condensing boilers are the most energy efficient Central Heating boilers on the market today. They achieve this high level of efficiency by removing the heat from the fuel it is burning and also cooling the products of combustion, which are normally wasted up the flue, so much so that the water vapour in them turns into liquid. This happens at around 58°C. For a boiler to cool the flue products this much, it has to have a larger, more efficient heat exchanger than traditional boilers.

What to do if water is leaking from the cylinder?

Copper water cylinders have a finite lifespan; if the water is leaking from the bottom of the cylinder it is prudent to take immediate steps to replace it, as the situation could rapidly get worse. Instructions for draining the cylinder are outside the scope of this section. If the water is leaking from a pipe union to the cylinder, this can normally be fixed by remaking the joint.

How often to service a boiler?

It is prudent, for safety and efficiency, to have the boiler serviced annually.


What is the danger if the boiler is not serviced regularly?

Most gasi registered gas technicians have personal experience of the dangers of not looking after gas burning appliances. We have come across a number of instances where faults have laid undetected due to lack of maintenance and have resulted in carbon monoxide poisoning of the house occupants. In severe cases lives could be at risk. Drowsiness, nausea, headaches are all symptoms. If you live in rented accommodation, the Landlord is legally obliged to have a safety inspection carried out annually. You can ask to see the inspection certificate at any time. If you are a Landlord, please bear in mind that most contractors performing 'CP12 inspections' or 'safety checks' do not check the internals of the combustion chamber or clean the unit internally. An annual CP12 is not a form of maintenance for your boiler. The best analogy is a car; no-one would expect their car to run properly by purely submitting it for the annual MOT.

What to do if you smell gas?

Turn off the gas supply at the meter. Open windows but do not turn any electrical items on or off.
Call Transco on 0800 111 999 in the first instance.

If the leak is on your pipework/equipment (the customer side of the meter) Transco will normally turn off the supply and advise you to contact a Corgi registered operative to make repairs.

What are the benefits of radiator thermostats?

The use of Thermostatic Radiator Valves prevents individual rooms being 'overheated'. Without TRVs the only temperature monitoring and control is done by a room thermostat; this covers the whole house rather than an individual room. Some rooms tend to warm up quicker than others, thefore a TRV can maintain comfort while potentially aiding economy. The new building regulations strongly advise that on new installations and significant upgrades, TRVs should be fitted to sleeping areas.

What is power flushing?

PowerFlushing describes the use of a high power pump and flushing machine used in conjunction with chemicals and heat, to dislodge and dissolve accumulated sludge and scale debris. This can rejuvenate a partially blocked system, giving faster warm up times, warmer radiators, greater efficiency and prevent the untimely demise of the boiler, pump and motorised valves.
Boiler manufacturers all advocate that a system is cleaned to British Standards prior to the connection of a new boiler. Powerflushing is the only way to comply. Modern, higher efficiency boilers are far more susceptable to water borne contamination than the older, cast iron heat exchanger types. We have seen new combination boilers virtually ruined after less than a year in service because of sludge. Our advice is to have an old system Powerflushed before connecting a new boiler.


What is a pressurized central heating system and what are the benefits?

A pressurized system uses an expansion vessel, containing a diapraghm and a compressable gas. The expansion in the water as it is heated is accommodated by the gas being compressed. The main benefit is the lack of a requirement for a 'filling and expansion' tank in the loft.

Is it more expensive to run an immersion heater relative to using a gas boiler?
Yes, in almost all cases.

What are the differences between 'combination' and 'conventional' boilers?

A combination boiler is where the boiler handles central heating and instaneous hot water requirements without needing external tanks or cylinders. Conventional boilers are merely a gas/water heat exchanger, the water from which is then routed using external controls to radiators and hot water heat exchangers (eg: a cylinder).

What is a SEDBUK rating?

This is a rating which tells the consumer how much of their gas is turned into useful heat output by the boiler (working in ideal conditions). There is still a percentage rating available, which makes more sense. This is normally stated in the manufacturers brochure.

What does Gas Safe registration imply?

The Gas Safe registration implies that the operative has achieved the technical proficiency in order to handle gas safely. It is illegal for a non-registered individual to work on any gas appliance. This was changed from Corgi in April 2009 and the new registration provider is the HSE with the "Gas Safe Register"(see below for the new Kite mark)

The Gas Safe Register

What is 'pumping over' in the Central Heating system?

'Pumping over' is where water is forced up the 'open vent' into the Feed & Expansion tank.
Causes can be;
- The hot water circulator pump is incorrectly sited
- the pump is oversized
- there is a restriction in the system


The authors and publishers of this site accept no liability, nor do they encourage you to do work that
should be undertaken by a qualified tradesperson. The content of this site is best viewed and discussed with your plumber.
Any original material on this site is not to be reproduced or transmitted without the written permission of
Andrew Dodsworth