13 minute read
Boiler focus
Behind the scenes with H21’s hydrogen research
With one of its first 100 per cent hydrogen boilers in place at the H21 test site in South Bank, Middlesbrough, the team from Vaillant involved with its installation and testing reflect on what it means to the industry, and what the results will feed into.
The H21 South Bank project, led by Northern Gas Networks with support from DNV, is carrying out research to assess the suitability of the UK’s existing gas network with a view to eventually transforming it to run on 100 per cent hydrogen. The site is key to helping the UK move towards the reality of using hydrogen as a fuel in our homes.
Vaillant has carried out a great deal of work testing the appliance in a lab, says technologies and training director Mark Wilkins, so this is a chance to get the boiler into the field and use it in the real world. The installation will start to inform the project on findings such as controlling flammability and installation requirements, ahead of hydrogen boilers being produced on a mass scale.
The trial will also validate the various steps required between installation and commissioning of the appliance and will start to inform the next stages of field trials as we move from a single house to a village, to a full town.
“We are very proud to be part of the field trial at Middlesbrough as it is a ground-breaking project in terms of the decarbonisation of the UK’s energy grid,” adds
Paul Honeyman, head of product development.
“This is the start of a new generation of energy products in the UK, and we are delighted to have a boiler running efficiently on 100 per cent hydrogen. The boiler itself is a result of many years of development and predevelopment work by our teams in Remscheid, Germany. This has involved multiple teams working on each separate element of the boiler, resulting in a high-quality product that will help pave the way for our net-zero future.”
Developing 100 per cent hydrogen
In terms of the product development taking place in the background, product manager David Parker says: “This boiler has been specifically designed to run solely on hydrogen from the outset. The burner is a smaller design, the ports are smaller and grouped differently because of the flame speed. Flame detection equipment is made specifically to read the hydrogen flame and the fan system designed expressly for this purpose.
“Vaillant is an active member of many heating industry associations that are also helping shape the future of hydrogen. The work we are doing here will help to understand how hydrogen products work in real situations and will inform consultations for the future.
“The site here was perfect as it uses existing gas pipework, adapted to replicate how the gas
would work across the grid on a domestic scale. This will help answer many of the questions installers have on how it will perform in our homes.”
As one of the engineers who fitted the boiler on site, Steve Dixon, field service support manager for Vaillant, says installing the boiler was not dissimilar to the products with which heating engineers are already familiar. “There was very little difference when installing a hydrogen boiler over a natural gas version. The boiler we have installed here is running very smoothly. At first fire, we were struggling to hear if it had ignited, it was so quiet.
Flue gases
“The main difference during commissioning and testing of the boiler is the measurement of the flue gases. We use O2 to determine correct combustion because there is no longer any CO in the products of combustion. The best advice I would give to installers when the time comes to install a 100 per cent hydrogen boiler is to follow the gas regulations and correct standards to the letter, particularly when purging the installation pipework.”
“Hydrogen boilers work the same way as a natural gas boiler,” adds Colin Box, technical quality manager. “It is a pre-mix gas and air appliance. For this project, we are using a combi boiler to power the heating and hot water at the facility, and we are getting the same outputs you would expect from a natural gas version.
“We are at the front of this development for a new type of gas and have moved the timeline forward and shown that the appliances can be ready. We have a boiler that is a similar size to what installers expect, and the installation is no different. This is a really big step.
“These projects are not only being monitored on site, but also remotely by our product team in Germany, so we can see how it is performing in a real-world situation. This is new technology, and we want to be there at the forefront creating the best products for installers and homeowners when hydrogen becomes mainstream.” ■
Time to rethink first-time fixes
How can gas engineers achieve a first-time fix to keep their customers happy while keeping their business efficient? Dave Griggs, managing director of Spares & Services at City Plumbing, has some ideas.
What is a first-time fix?
Many companies define a first-time fix as dispatching an engineer to attend a customer’s home to assess a problem, then returning to fix the problem once the faults have been diagnosed and spare parts ordered. This means that the problem isn’t actually fixed during the first visit and, for the homeowner, the problem isn’t resolved until their heating and hot water are back up and running.
In my opinion, first-time fix rates should be focused on the restoration of heat rather than an engineer identifying the problem and setting a date to return to fix it. Restoration of heat is the number one priority for the customer and translates directly into satisfaction, repeat business and improved profitability. It’s for this reason that heating engineers need to aim to achieve a true first-time fix.
Using data to your advantage
Much has changed since I joined the industry in 1991 and gone are the days of having to see a boiler in the flesh to understand what parts are needed. Now companies and managers can invest in data and apps to do some of the legwork.
Through the use of data and the increasing number of apps, gas engineers can find out what parts are needed and their availability, service history, and resolution steps for similar issues, all before attending a call-out.
Collect as much data as possible about the heating system in the property, particularly when conducting repeat visits or working for landlords. Although homeowners usually know what make and model their boiler is, it’s the finer details that determine exactly which spare parts are needed, and details are not easy to identify to the untrained eye.
Preventative maintenance
Having this data can also enable businesses to compare the failure rates of one boiler against another so that they can advise their customers on the most reliable boilers while simultaneously improving their business.
This use of data can also be combined with monitoring systems that use diagnostics to provide real-time fault notifications even before the homeowner has spotted the issue; this is particularly useful to maximise the safety of elderly or vulnerable customers who are unable to raise an alert themselves.
As an industry, we need to aim to get the right part in the right hands at the right time, as it is this that will ensure consistent first-time fixes for householders. Using the technology available to improve your service will go a long way towards making this possible.
Let’s talk
Better communication with customers on how to resolve issues like repressurising the boiler or bleeding radiators can also free up your time so that you can prioritise those customers who have bigger problems.
You can triage your calls to determine whether the issue can be resolved by the customer themselves or whether you need to visit their property. And keeping an accurate record of the heating systems you maintain will help you to identify and source the necessary parts.
It’s high time that first-time fix rates were measured on the restoration of heat and customer satisfaction. Data-led fault-finding can make this a reality: by understanding heating systems in more detail, we can reduce the need for unnecessary call-outs, ensure that replacement parts are readily available, and ultimately, ensure that your customers are happy with your service. ■
To find out more about how City Plumbing is helping engineers improve their first-time fix rates please email:
faultfinder@cityplumbing.co.uk
Priority domestic hot water: an untapped solution
The nation’s attention is fixed on how to cut energy costs. Here, Alpha product engineer Jonathan Kidner looks at how priority domestic hot water can be a quick fix now.
Two issues are facing UK homes this winter: the cost of living; and living more sustainably. But in the midst of the energy crisis and with families facing a brutal ‘eat or heat’ choice this winter, the cost of running their home is eclipsing any desire or sense of urgency to reduce their carbon footprint.
However, existing technology that can offer a remedy now is being under-utilised due to a lack of awareness and understanding by both homeowners and heating engineers.
Traditionally, heating systems consisting of a gas boiler and hot water cylinder are set up with one ‘go’ signal, regardless of whether they are firing for heating or hot water. They then send the same
high-temperature water (somewhere around 70°C-80°C) to either the heating system or to heat up the hot water cylinder. This is a simple but somewhat wasteful set-up and can impede the boiler’s ability to condense effectively.
Priority domestic hot water (PDHW) involves separating these two functions. This enables low-temperature water to be sent around the heating system or a short burst of high-temperature water to the hot water cylinder. The benefit is that the heating (which is on for longer) can be run at lower temperatures to maximise savings while still heating the hot water cylinder beyond 60°C to kill legionella bacteria.
Running PDHW, particularly with a Delta T (DT) controlled pump, ensures that a system designed to run at 70/50 will see boiler efficiency at around 90 per cent compared to around 86 per cent efficiency from one run at an 80/60 temperature. Energy consumption is reduced, therefore lowering the overall household bill.
Regardless of the cost benefit to homeowners, PDHW also ticks the box when it comes to Building Regulations. The new Part L insists on higher building performance in terms of energy efficiency. However, we have often observed Part L being seen as a minimum standard: PDHW is one simple way in which heating engineers can go above and beyond to improve a building’s energy rating.
To take advantage of PDHW,
you need a boiler that can differentiate between the demands for heating and hot water. Boilers such as this incorporate control valves that shut off the heating when the hot water cylinder is being heated, preventing high-temperature system water from being sent wastefully around the heating system.
You can further maximise the benefits of PDHW by controlling the flow rate of system water going to the coil of the hot water cylinder. In addition, the boiler’s output can be tailored to match each individual home’s heat loss and hot water cylinder coil rating.
Although not all boilers have this inherent functionality, most can be adapted to incorporate PDHW without too much disturbance by using a diverter valve kit. This is a straightforward task because the control valves, controllers and wiring required are all very much industry standard. No special skills are required except for an awareness that the technology exists and making sure that everything has been installed and wired correctly.
Saving energy
The appeal for homeowners is that this won’t cost a fortune to install (usually around £200) but it will save energy and reduce the overall cost of providing heating and hot water without losing any performance in either.
Many domestic customers won’t know or understand about this simple remedy. By telling them about the benefits, ease and low cost of installing PDHW, heating engineers can offer an option to help alleviate the growing pressure of the energy crisis. Homeowners should be assured that the valve itself is very much a ‘fit and forget’ solution. They won’t need to routinely maintain or replace it. Neither will they need to learn about any complex new controls or special new ways to run their system. ■
One way to provide PDHW is to use Alpha’s diverter valve kit. It operates as a hot water priority valve, meaning that if the heating is on and there is a hot water demand, the valve will divert the primary heat to the cylinder until the cylinder sensor is satisfied.
Pump up the flow rate
Low water flow can reduce the efficiency of combi boilers, which means that you should consider the water pressure and flow in the property before you install one, says Salamander training manager Mike Oxley.
Over the past two decades, combis have become much more common, providing an efficient solution for most households. In fact, condensing combination boilers have risen from 1.7 per cent of installations in 2003 to become the most common type in all homes by 20191 .
For the most part, they are mains-fed, meaning that they are supplied directly from the mains water, which is then heated and distributed throughout the home. Because they receive water directly from the mains, the flow rate throughout the system will be dictated by the water flow from the mains.
The boiler’s flow rate indicates how many litres of hot water it will deliver per minute. This is determined by the flow rate of the mains water supplying the combi boiler and the boiler’s ability to heat the water to the set temperature. The more powerful the combi, the faster it heats the water coming into your home.
Given that combi boilers can deliver various flow rates, it is important to consider the home’s water needs to ensure the right boiler is fitted to meet the property’s requirements. A home with high heat and hot water demand will require a more powerful boiler.
Some factors to consider
when determining your customer’s needs include the number of occupants, the size of the house and the number of bathrooms. But it’s important to remember that the combi’s output flow rate is limited by the flow of the incoming mains water. So, installing a boiler that has a flow rate of 14 L/min in a system where the mains water is only providing 10 L/min will mean that the boiler will be limited to delivering 10 L/min.
How can you improve the mains water supply?
When the flow rate of the mains water supplying the property is below the home’s water
requirements, an in-line pump or accumulator tank are both great options to boost it. And doing this means that you can install a combi boiler with a flow rate that matches the needs of the property.
In-line pumps, can boost the water flow to 10 L/min and 12 L/min respectively. These pumps can be fitted to boost the water supply up to 12 L/min, meeting the requirements of the Water Supply (Water Fittings) Regulations 1999.
When the property has a greater demand of more than 12 L/min, then stored water is required. Accumulator tanks should be installed, which can provide flow rates of up to 36 L/min per tank. Water is stored under pressure and then released into the system to assist the incoming mains water when an outlet is opened.
You should look to install a pumped tank when the home’s mains water pressure is less than 2.0 bar and/or the mains water flow is less than 12 L/min.
Unpumped tanks are suitable when mains water pressure and/ or flow are good, but the demand required by the combi boiler is greater than that which the mains is providing naturally. ■
