Name: Huw Jenkins
Business: Thornhill Plumbing & Heating
Please tell us about a project you are particularly proud of – what was the problem and how did you solve it for the customer?
I was approached by a family living in a large detached house with a family bathroom and two ensuites. They had been suffering from numerous faults with their heating system also inadequate, very noisy and unreliable hot water. The customer was struggling with inefficient hot water and heating, temperamental shower pump, no control over the individual room temperatures, the heating and the hot water were very difficult to control, the hot water was too hot at the basin taps and the radiators were out of balance, so some radiators did not heat up at all.
The heating system had become very unreliable and my customer wanted it replaced with a solution that would be reliable, quiet, efficient and give a good flow rate of hot water.
The system also needed to be fully controllable but at the same time easy to operate.
My first course of action was to decide what type of heating and hot water system would be ideal for this house and its occupants; how to make the best decision and offer solid advice to the customer so they could make a well-informed choice.
On an installation, a lot of time and thought is put into the planning stage. I need to make sure that the system I specify is perfect for the building without doing any unnecessary work to keep costs to a minimum and to minimise any disruption and downtime.
The customer was asking for the current system to be replaced with a combi boiler as they had been recommended this option.
Combi boilers have many advantages. They are small so save a lot of space, the heated water instantaneously so can use less gas than a stored hot water solution, and when replacing a conventional system with a combi system you are doing away with most of the components of the heating system such as the header tank the cold-water storage cistern, pipework in the attic and airing cupboard, zone valves, pump, hot water cylinder and shower pump. All of these components are replaced with components within the boiler and are then covered by the boiler warranty common so fewer things to maintain for the customer.
A combi-boiler, however, is only suitable for properties with lower demand for hot water. As the combi heat water instantaneously, it can only ever serve one outlet at full capacity. If someone is in the shower, and then another shower or hot tap is turned on, then the heated water has to be shared between the two outlets which will lead to the shower running cold or decreasing inflow rate down to a dribble.
Another disadvantage of a combi is that a is no backup for the hot water – should there be a problem with the boiler or the gas supply as there is no electric immersion heater for such instances. Finally, the combi boiler utilizes a diverter valve, so can only heat either radiators or hot water; not both together. This becomes a problem when more than 3 people live at the property and a lot of hot water is being used. For example, on a cold morning, if all of the occupants are showering one after another, the heating will be off the whole time the hot water is being used. This can cause the house to be cold as the heating is not on when needed.
I needed to calculate the hot water requirement for the house so I asked the customer how many people live in the house and how often they had guests. I also tested the incoming mains pressure and flow rate.
After my initial assessment, it became clear that a combi-boiler would not be the right choice for this installation as the hot water requirement would be above was a combi-boiler could provide. I instead thought the best option would be an unvented cylinder which would give mains pressure hot water to many outlets simultaneously. Fitting a system boiler to work in tandem with the unvented cylinder would also give us many of the benefits of a combi-boiler such as getting rid of the storage cisterns and pipework in the attic and airing cupboard. The system would be pressurised instead of running an open vented feed and expansion cistern which has many drawbacks and is becoming outdated technology.
Whenever changing a boiler from a conventional open vented boiler, I always like to suggest a system boiler. The main reason is that you do away with the feed and expansion cistern (which leaves the system water open to the atmosphere and introduces oxygen to the system which in turn causes corrosion which is the number one cause of system problems).
I explained the above points to my customer in easy-to-understand language so that they were making an informed and correct decision for the heating installation.
After calculating the hot water requirement for the house, I then carry out a heat loss calculation for each room and calculated (for a given outdoor temperature) the lowest flow rate I could send to the existing radiators. This included assessing insulation levels and the size and efficiency of the windows etc.
Efficiency is always born in mind and is important to upgrade the parts of the system that need upgrading and equally important to not be wasteful and replace things that do not need replacing. Most of the radiators will be of the correct size for our requirements and in good condition, apart from many did not have thermostatic control.
The customer did not want to lose the airing cupboard, although she did struggle to get clothes into the as had to go above the monster 250l open vented cylinder. Her house was pristine, very neat and tidy and everything had its place. The utility room backed onto the garage and was next to the gas meter.
To maximize space in the house and to minimise heat loss through primary pipework between boiler and cylinder, I decided to fit the boiler in the utility room and the cylinder on the other side of the wall in the garage. I could convert the airing cupboard by removing all of the heating and hot water components and fitting a small radiator which was give the customer much more storage space and a much easier and more accessible airing cupboard.
I measured up a wall cupboard in the utility room and worked out how I could fit a boiler in there but hide all pipework behind the boiler. This would make the boiler as unobtrusive as possible, hidden away, but should the customer want to get to the boiler, they wouldn’t have to go out into the garage.
I studied the garage and found a way to rearrange the shelving so we could fit in the cylinder and associated pipework components leaving lots of access to maintenance but maximising space in the garage.
I went away and did my research on exactly what components would fit my plan perfectly, taking into consideration my energy calculations and space requirements.
Once I knew the dimensions of what I had selected to fit, I do a schematic drawing of my planned installation so that the installation would be as efficient as possible, perform excellently, take up as little space as possible and be easy to maintain/service.
The boiler selection was important as I wanted this to be quiet, efficient, reliable and be capable of running the time of system I have specified.
The modulation of the boiler and the flexibility for the complexity of the boiler parameters are also important.
The maximum heat output was not oversized for sake of efficiency and longevity. I asked the customer if she was planning to extend the house in the future, or upgrade the insulation and windows so I could account for this.
I took into account the current heat requirement of the building and possible changes to this heat requirement. I advised the client of upgrades to the windows and insulation of the building, and bear that in mind when designing and specifying my system as the heat requirements were likely to change in the future.
Upon taking water samples from the existing heating system and looking at my heat loss calculations it was clear that there was advanced corrosion within the system which was unbalanced, inefficient, unreliable and oversized.
I needed to put the smallest heat input into this building as possible that would still adequately heat the building through the coldest days. I needed to go away and do my research for any questions I had about the specification.
Which products did you select for the job and why?
The hot water cylinder was sized at 210l according to the hot water demands of the occupants, making sure not to oversize which would end up wasting energy and space.
The heating system would have weather and load compensation for maximal comfort and efficiency. the hot water would be set up as priority hot water which would give excellent hot water performance was allowing the heating to run at as low a temperature as possible.
Low temperatures are desirable in heating systems as they less corrosion, less thermal shock to the system, less stress on expansion vessels, prevent cavitation at the pump, keep the air in the house cleaner and more comfortable, less system noise, less heat lost through pipework, more efficient combustion, cleaner emissions, less heat wasted through exhaust gas, the boiler will condense more as more heat can be recovered by the heat exchanger. Also, the temperature of the rooms can be turned down as the comfort level of the heating will have increased. We are limited in the temperature of the heating – down to heat loss of the building and size of the emitters/radiators, this is why heat loss calculations are so important.
I considered the use of a low loss header, with this solution was not right for this particular job as this could have negatively affected our efficiency due to higher return temperatures and cycling of the boiler.
The products I selected for this installation were specified to meet the customer’s needs and my calculations.
I specified ATAG i 24 system boiler which has an excellent user interface, many parameters, can modulate down to 5kw, comes with a 14-year warranty and lifetime warranty on the main heat exchanger.
The boiler was sized so we could run the boiler at almost its full capacity to achieve the current heating and hot water requirement and range rate the boiler down in future should be needed, also adjusting the weather curve should the U value of the building change with any future works.
The choice of the boiler was also due to the heat output, the modulation ratio, the ability to set the pump speed, the quality of the components, proven reliability and backup from the manufacturer along with the long warranty offered. I do have my preferred manufacturers and as I work on many different boilers in my servicing and repairs, I get a feel for what boiler would be correct for each particular situation. Another reason for selecting this boiler is the packaging is 100 per cent cardboard (no polystyrene).
I also specified ATAG priority hot water valve for a number of reasons. When using atag priority hot water with an ATAG system boiler we can achieve the radiators to be weather compensated (low-temperature) but also have the hot water to be rapidly reheated; as the full power of the boiler will be redirected to the hot water cylinder whenever the hot water heater to be replenished. We can also store the hot water at a lower more comfortable temperature which will save massively on gas bills and wasted energy. This will also give much more comfortable hand washing and prevents any possible scalding to especially vulnerable people such as children and the elderly.
This is made possible via the boiler and priority valve carrying out a thermal cleanse once per week to kill any potential bacteria in the cylinder.
My cylinder of choice was a megaflo indirect eco cylinder for its excellent insulation (as it would be situated in a garage), it has an air gap so no expansion vessel is required, has excellent heat recovery rate, and has a lifetime leak guarantee.
Or the heating controls a specified ATAG One zone smart heating controller as this will give the customer the flexibility to use the heating and hot water remotely and easily using their devices, but also connected to my phone for remote diagnosis of any boiler faults. The one controller is also great to be used in conjunction with the weather and load compensation of the boiler has the boiler and function with room temperature influence. This optimises efficiency, comfort and performance. The one controller also looks very smart and fits in well with the decor of the home.
For the hot water to perform as best as possible, I upgraded the pipework between the mains stop tap and cylinder inlet control group to 22mm pipe with a minimum of fittings and changes of direction to have maximum flow rate to the outlets. We ensured the cold outlets to the rest of the house was balanced at the same pressure is the hot water, in order to have the showers and mixer taps work as best as possible. The outside tap was left at full pressure to utilise higher pressure or watering the garden and cleaning cars etc.
The pipework was insulated in foil faced glass wool insulation. This insulation was chosen as the best performing insulation (0.043 W/MK@50°c) also glass wool is made of more recycled material than mineral wool and is less harmful to the environment than polyethylene foam pipe lagging which is commonly used. The foil-faced lagging would be ideal in an unheated garage, also looks very smart.
All of my pipework is done in copper as I feel it is still the superior material for pipework for many reasons. Copper performs better and looks better than plastic alternatives, which is also called the world’s most reusable resource.
For control of the individual room temperatures, I specified danfoss B2 dynamic self-balancing radiator valves to be fitted to all radiators. The Danfoss radiator valves I have found to have a very accurate temperature sensor and we can give each radiator a set flow rate that is not influenced by what is happening elsewhere in the system. This way by commissioning using the installer App we can achieve desired delta T across every radiator for a set flow temperature. This is ideal, the emitters would always perform as designed, even if the valves were played about with. The valves could be set at different values down the line should our design flow temperature need adjusting. We can also calculate the total flow rate through the system so we know the correct amount of pump head that is required at maximum load.
Tell us what was different or unique about this job? Why does it stand out?
Once the job was accepted, I had to plan to work around the occupants and their families. Floorboards and ceilings had to be opened to identify and assess all pipework. Any redundant Plumbing pipework had to be removed for legionella prevention, the gas pipework was calculated to give the correct working pressure to the position and power of the boiler and any redundant gas or heating pipework to be removed. As much of the system as possible was kept intact to keep costs, disruption and environmental impact to a minimum. A plan of how to connect/adapt the heating system and various elements was made along with a schedule of work and which areas needed to be worked on in which order.
As the old system was to be removed and made good so there was no sign of where we have been working or removing any components of the old system
The health and safety of the building occupants was of paramount importance during this project, and everyone was informed of what areas they could and couldn’t use as work was progressing. Although many becoming less concerned about the covid pandemic, I still wear a face mask on every job for peace of mind for my customer and continue to sanitise anything I’ve touched as well as my tools at the end of the workday.
Whilst working we made sure that we were very respectful to the customers by making sure we didn’t turn the water off for long periods we protected the customer’s property with dust sheets, always refer to the customer using their names and lightly asked if we could use the toilet. We often get the compliment that the house is cleaner when we had finished the job than before we had started the job, I feel this is very important as tradespeople do tend to have a reputation for being messy.
The pipework was designed to be as streamlined as possible following a logical sequence and all to be concealed, supported correctly and adequately insulated whilst bearing In mind factors such as system noise and turbulence. Pipework is very important to me and I am always practising to perfect my pipe bending, soldering, always deburring pipework and minimising joints and changes of direction etc. Even if the customer cannot see or appreciate these things, they are essential to me.
I also hold my apprentices to high account and want them to have the very best training possible as I had and to aspire to become better than me. There is a lack of youngsters (especially females) coming into the trade and being trained properly. I find much satisfaction in passing my skills on and find it helps me learn my job better when I have to show someone else how to do it. Other skills are important to pass on such as dealing with people and being conscious, meticulous and organised.
My cylinder, pipework and the components that needed to be exposed were set out with a low profile and as neat as possible to maximise space and aesthetic beauty. The heating installation became a feature instead of what is usually an inconvenient eyesore.
The system volume was calculated so I could provide adequate means of expansion and filtration for the system water along with correct dosing of the fill water.
I incorporated many special touches into the installation with future maintenance in mind. I fitted flushing and drain points to the flow and returns of the boiler and also fitted convenient full bore isolation valves and drain points to all relevant sections of the system to ensure anything could be isolated if needed. I also ran a drain point directly outside so the heating system could be drained from outside in case of an emergency which would be the quickest way to drain the system in an emergency as no hose pipes etc. would be required. I also incorporated a lever valve into the cold feed to the bottom of the cylinder and connected this to the discharge pipe from the cylinder so should a rapid drain down of the cylinder required, this could be done in via the discharge pipe. I made the valve tamper proof so it could only be operated by a maintenance engineer.
Upon flushing the system, a power flush was performed, but any radiators with an excess of sludge were removed, taken outside and flushed through with mains water whilst agitating the radiator. I find this method to be the best for heavy deposits.
Although replacing items is usually a good shout, we still have to be mindful of costs and environmental impact – does it really need replacing?
Upon commission of the system, an infrared camera was utilised to accurately check how evenly everything was heating up and to fine-tune the system.
The boiler parameters were set to the desired values as calculated. The system was deaerated.
On all of my jobs, I take a concise and easy to understand video of how to use the system and what to do if there is a problem. I send this to my customer for future reference and this video could be shared with whoever in the building needs the information. A video is handy as often times people forget what you have told them face to face.
The result was a perfectly balanced system, a warm building and a boiler constantly running at the correct output instead of cycling on and off which reduces the efficiency and lifespan of the boiler.
And finally, tell us what the end result was for your customer?
The customers were over the moon with the result as they now have a silent heating and hot water system that looks very high tech is extremely easy to control and they are finding the temperature in the house to be much more comfortable. They are very impressed with the increased performance of the hot water. They now have a much larger airing cupboard which has temperature control so the airing cupboard can be kept at a particular temperature as can every other radiator in the house which are all heating up at the same time and to the same temperature.
We made a very neat job of making good with the old system was including matching the brickwork to the outside of the house in such a way that you cannot see where the old boiler was now. They have also told me that they invite any guests as come to the house into the garage so they can see the cylinder part of the install as they think it looks spectacular and futuristic.
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