Welcombe Hotel, Stratford-upon-Avon
Building: Hotel plant room refurbishment
Products: Wessex ModuMax mk3 boiler, Stratton mk2 wall hung boiler
Application: Space heating 540kW/588kW/154kW; DHW 2,149 L/h
The Welcombe in William Shakespeare’s birthplace Stratford-upon-Avon is one of Hallmark’s many prestigious hotels in the UK. Situated in 157 acres of landscaped grounds with access to its own spa and golf course, it presents a relaxing retreat for its guests and day members. Like many hotels, the Welcombe was facing the issue of old boilers becoming unreliable, nearing the end of their serviceable life, with spare parts being difficult to source. Over the course of two years, Danny Bulch, Director at Cedar Green Projects Ltd, replaced the boilers, gas fired water heaters and hot water calorifiers in the hotel, spa and golf club with varying products from the Hamworthy range. The products were chosen thanks to their ability to suit a range of applications and overcome the main challenges of the project: Refurbishing a hotel during peak heat requirements in winter, overcoming access issues to the plant room and accommodating different fuel options.
Replacing the spa boilers
The Welcombe’s spa offers guests an indoor and outdoor pool, luxury treatments and a fully equipped gym. Five large cast iron boilers with a combined output of approximately 500kW supplied heating and hot water to the spa. As the sections of the boilers kept splitting and were becoming unreliable, a replacement was needed. Danny chose three Hamworthy Purewell VariHeat cast iron floor standing condensing boilers with a combined output of 540kW to substitute the five old boilers. They are the only ErP-compliant cast iron condensing boilers in the UK.
“Hamworthy’s Purewells are compact and sturdy cast iron boilers with large waterways, we use them in our temporary boiler rooms for this very reason. Looking at the requirements of the spa, there wasn’t a moment of hesitation in choosing these boilers as we know them so well.”
To accommodate the hot water requirements, PS200 and PS500 Powerstock hot water calorifiers were chosen. These glass-lined indirectly heated water heaters provide a combined hot water output of up to 2,149 litres per hour at 50 degrees differential temperature. They also benefit from a recovery time of only 20 and 18 minutes respectively.
Finding boilers to accommodate the heating and hot water requirements of the main building
Two large atmospheric boilers on a fan dilution system previously delivered heating and hot water to the main building of the hotel. One of the boilers suffered from a split heat exchanger which meant the second boiler was the only one left working. Danny opted for Hamworthy’s Wessex ModuMax mk3 196/588V, a small modular condensing boiler with stainless steel heat exchanger that has a 10-year warranty, to replace the old boilers. The chosen model can deliver an output up to 588kW from less than a square metre of footprint and consists of three individual boiler modules which can be flexibly stacked on top of each other to suit difficult plant room layouts. The boiler can efficiently match the heat load from 39kW incrementally all the way up to 588kW. This is possible thanks to the 5 to 1 turndown ratio per module, combined in a three-high stack, it then becomes 15 to 1. The higher the number of modules, the higher the turndown ratio of the system.
“We chose the Wessex because it delivers a high output from a small footprint and it’s a tried and tested product with stainless steel heat exchanger. I’ve been working with Hamworthy for a long time and I like their products because they are reliable. We’ve installed a large number of Wessex ModuMax which means we’re very familiar with the product. Thanks to its compact size, the Wessex fitted onto the footprint of only one of the old boilers, so we’ve effectively halved the space needed for the heating equipment.”
Challenges of running a hotel and replacing boilers at the same time
The replacement was undertaken during winter while the hotel stayed open; with high heating and hot water requirements which made it more challenging.
“The remaining old working boiler kept the hotel running while we were installing the Wessex ModuMax on the footprint of the second, failed boiler.”
When atmospheric boilers are replaced with condensing models, changes to the flues are required to deal with the acidic condensate. In this case, a FuranFlex flue liner was applied to the inside of the old chimney which was running through a brick stack to the boiler room. New twin wall flue components were then used to connect back to the new boiler from the liner.
Working with Cedar Green Projects, Midtherm Engineering were employed to design, supply and install a new flue system and boiler room air supply and extract system at the historic hotel in Warwickshire.
“Whilst we installed the boilers, Midtherm were able to set up the flue using the FuranFlex flue liner. Once finished, our team of coded welders undertook some complex positional welds whilst the hotel remained open for business as usual. Within only a few hours, the hotel was running on the new Wessex boiler, a virtually seamless changeover with no noticeable loss of heating or hot water.”
Ian Ford, Flue Division Manager at Midtherm Engineering, commented,
“First of all, we erected a scaffold tower from the ground to above roof level with the help of our partners Perry Scaffolding. This included a platform built around three sides of the chimney stack to provide safe access to carry out a camera survey of the six flues within the chimney. In keeping with a building of this age, the routes of the flues from the chimney top were complex, and in some cases blocked. Ultimately, it was found that there was only one flueway which linked the boiler room to atmosphere, with others serving fireplaces in the rooms in that area of the hotel. The problem was that the path from the boiler room’s chimney breast to the top of the chimney had multiple offsets, and the cross-section was rectangular. This meant that traditional stainless steel flue liners were not practical, and because of the condensation and pressure created in the flue by the Wessex ModuMax boilers, we needed a proven and reliable flue liner which could negotiate the awkward route, as well as changing in shape to match the rectangular flueway in the chimney.”
“FuranFlex liner was our clear favourite for this application, delivering the much-needed flexibility. FuranFlex is a glass fibre reinforced thermosetting resin flue liner. Essentially, the liner arrives on site in uncured condition. Resembling one leg of a pair of trousers, the soft form allows the liner to be passed through a complicated flue route before being suspended from the scaffolding, once positioned. Then, the liner is inflated using fast blowers. When complete, a camera survey is carried out to ensure it is free from twists and damage. A bank of steam generators is then connected to the plastic inner sleeve of the liner to slowly cure it under heat, turning it into a hard and smooth material which resembles carbon fibre in appearance.
Lastly, we just had to connect the liner to the boiler and install the new mechanical input ventilation system to complete the installation and make it safe and efficient.”
The whole installation was subsequently tested and commissioned by Hamworthy. Danny commented,
“We chose commissioning from Hamworthy, as it extends the standard warranty terms. Since the installation, the hotel has been benefiting from the Wessex’s great fuel efficiency and reliability.”
Overcoming access issues to the Welcombe’s golf club plant room
The hotel’s clubhouse with function rooms and sports bar was the last part of the refurbishment project at the Welcombe. The old boilers were installed in a loft space plant room with awkward access.
“We wanted a Hamworthy product which is wall hung and made of stainless steel. An LPG boiler was required as there is no mains gas to this part of the estate. We opted for two boilers, as these are smaller and lighter than a big model and provide back up for servicing and maintenance. Making use of multiple boilers means we can benefit from better load matching thanks to the combined higher turndown ratio.”
The chosen new boilers were two Stratton mk2 S2-70 stainless steel wall hung condensing boilers with 5-year warranty and 154kW total output. Additionally, the two boilers have a combined turndown ratio of 10 to 1 for flexible load matching from as little as 15.4kW up to its full output of 154kW.
A successful project
Cedar Green’s longstanding partnership with Hamworthy Heating allowed them to become familiar with the complete product range, from technical specification to installation and servicing. For this reason, it was easy for Danny to choose the right product for each application. Thanks to the expertise of Midtherm Engineering, even the difficult part of preparing the flue to cope with condensate from the new boilers could be resolved without extensive changes to the existing flue system. The hotel boilers are now all Hamworthy models across the board, simplifying aftercare. With the installation of the new energy-efficient equipment, the Welcombe Hotel benefits from reliability and standardisation. The installation of multiple modular boilers ensures a backup is available should a boiler need servicing or maintenance. Additionally, the combined turndown ratio of several boilers also lowers operational costs due to fuel savings, helping the Hallmark Hotel Group with their constant progression within the Green Tourism Sector. This hotel, like a number of other Hallmark hotels, has benefited from investment in energy-efficient boilers and associated mechanical plant together with a continued room refurbishment programme to improve guest experiences.