Specifications

Pressure Relief Valves
All heating systems incorporate pressure relief valves. In the event of a very high pressure build up in a
sealed system due to a malfunction, the pressure relief valve will open up to relieve excess pressure and
prevent damage to the system. These valves should be routed to the ground or a drain/collection vessel and
installed in a suitable location so as to cause minimal damage if they are called into action.
Ventilation / Exhaust
A boiler must have a secure air supply for safe operation. This can either be in the form of a controlled
dedicated air supply directly to the appliance or in the form of a permanent ventilation opening to the
space in which the appliance is located. Best practice is to rely upon dedicated ventilation and not on air
inltration and / or leakage into the space. The size of the opening depends on the size of the appliance.
Your supplier should be able to size this correctly. In addition, extractor fans may interfere with the operation
of the appliance causing smoke to spill out of the appliance to the room. The ue is critical to the safe and
ecient operation of a wood boiler. It is the ue which helps the boiler to breathe. Its task is to evacuate the
exhaust gases, and to draw in new air to keep the re burning. Even if a boiler has a mechanically assisted
draft function, it is still very important to ensure that the ue is suciently high to provide natural draft in the
event of a power outage.
Technical Guidance Document Part J of the Building Regulations provides guidance on ventilation and ues
for solid fuel appliances.
Mounting Base
A boiler should be placed on a hard, level and non-combustible surface. Typically this would be a concrete
oor or base that is purpose made for the boiler. Avoid placing on oors covered with lino or carpet,
suspended timber oors or oors nished with timber.
Air to Fuel Ratio Control (Lambda Control)
Boiler eciency is inuenced by the amount of air introduced into the combustion process. Too little air
results in incomplete combustion and loss of eciency as not all the energy in the fuel is being extracted.
Too much air provides complete combustion but wastes energy heating the excess air which goes out the
ue rather than being used where it is wanted. It is therefore always a primary objective to get the ratio of
air to fuel just right. One way this is achieved is by setting an air inlet to the boiler, typically during servicing.
While this often works well with gas or oil systems because the fuels are very uniform and the characteristic
operation of the boiler does not change signicantly over the course of a year, wood boilers, especially chips
Burn back Protection Measures
Interruption design – pellet drop Twin-auger design with rotary pocket
feeder
Boiler showing melting tube(in blue)