22mm Accumulator Kits
APS 22mm Upstream Kit
- Established 1975
- Trusted by thousands of customers
Supplied as the Mainsboost Upstream Monobloc 22/28mm. This kit now ships as a single pre-assembled unit rather than a box of loose fittings — the same upstream regulation controls every accumulator and Mainsboost install needs, combined into one compact body.
Pressure regulation, backflow protection and straining are all built in, so the cold mains feed meets WRAS and water authority requirements with far fewer joints to make.
- One pre-assembled unit — faster fit, fewer leak points
- Suits 22mm and 28mm connections
- WRAS approved materials
- 2 year warranty
Please note: the accumulator connection fitting and isolating ball valve are not included and should be ordered separately.
More about this product
Supplied as the Mainsboost Upstream Monobloc
Your APS 22mm Upstream Kit is supplied as the Stuart Turner Mainsboost Upstream Monobloc 22/28mm — a compact, pre-assembled unit that delivers exactly the same upstream regulation as the traditional multi-part kit, but built into one body. Instead of plumbing together a set of separate gauges, valves and fittings, you fit a single component.
It applies the regulation controls required on the incoming cold-water mains for an accumulator or Mainsboost installation, keeping the system compliant with WRAS and water authority requirements.
One unit, not six separate parts
A traditional upstream line-in kit is built up on site from individual components. The monobloc combines those same functions into a single compact casting, so there are fewer joints to make and fewer potential leak points.
- 2 × pressure gauges
- Lever isolating ball valve
- Pressure vessel fitting
- Pressure regulating valve
- Y-pattern strainer
- Double check valve
Multiple fittings, multiple joints, longer install.
- Pressure regulation
- Backflow protection
- Straining
All in one pre-assembled body — quicker, cleaner fit.
What it does
Sitting on the incoming cold mains ahead of the accumulator or Mainsboost system, the monobloc:
- Regulates the incoming mains pressure to the level the system is designed for.
- Prevents backflow, protecting the mains supply and meeting water authority requirements.
- Strains the incoming water to keep debris out of the system.
Features
- Compact, integrated design
- Simple and convenient installation
- Suits both 22mm and 28mm connections
- WRAS approved materials
- 2 year warranty
Compatibility
The Mainsboost Upstream Monobloc is designed for use with Stuart Turner Mainsboost systems and is the integrated equivalent of a 22 or 28mm upstream line-in kit. If you’re unsure whether it suits your accumulator or booster set, message us on WhatsApp before ordering and we’ll confirm.
Standard delivery:
Standard delivery is free on most orders. Some items may incur a delivery charge depending on weight, size or value. Any applicable charge will be displayed at checkout.
Deliveries will typically be made between 7am and 6pm, Monday to Friday (excluding public holidays).
Next day delivery:
Next working day delivery is available for a £16.50 + VAT delivery charge.
Orders must be placed before 12 noon to qualify for next working day delivery. Orders placed after 12 noon on Thursday but before noon on Friday will be delivered the following Monday. Orders placed after 12 noon on Friday will be delivered on Tuesday.
Pallet/Large/Difficult items:
Some large, heavy or difficult to transport items may incur an additional delivery charge. Please contact us for a delivery quote before ordering.
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Frequently Asked Questions
Quick answers to common questions about the APS 22mm Upstream Kit. For technical specifications, see the product details above; for sizing or installation advice, contact our team. If you have any other questions, we're happy to help.
What is a mains pressure boosting system?
A mains pressure boosting system increases the pressure and flow of water from the incoming mains supply into a property. It typically combines a pump and a storage or expansion tank, drawing water from the mains and delivering it to taps, showers and appliances at a stronger, more consistent pressure. They are used where the incoming mains is too weak to serve modern outlets reliably.
When do I need a mains booster pump?
You normally need a mains booster if static mains pressure is below 1.5 to 2 bar, if showers run weakly when other taps are open, or if combi boilers struggle to deliver hot water. Anglian Pumping recommends checking static pressure at the stop tap before specifying a system, then choosing a model rated for the number of bathrooms and outlets in the property.
What size mains booster do I need for my home?
Sizing depends on the number of bathrooms, the type of fittings and the static mains pressure. As a guide, a 1 to 2 bathroom property with combi boiler or single shower often needs 1.6 to 3 bar boost. A 2 to 3 bathroom property typically needs 3 to 4.5 bar with an integral break tank. Larger homes need a tank-and-pump system such as the DAB Esybox with Esytank or a Powertank set.
What is an accumulator tank?
An accumulator tank is a pressurised vessel that connects directly to the mains supply and stores water under pressure. When a tap or shower opens, water discharges immediately from the vessel at full mains pressure rather than drawing only from the street main. This delivers stronger, more consistent flow at peak times. Accumulators have no pump and no moving parts so they are maintenance free and silent.
When should I use an accumulator instead of a pump?
An accumulator is the right solution when static mains pressure is adequate – above 2 bar – but flow is poor or drops during peak demand. It boosts available flow without adding a pump, energy use or noise. If static pressure is below 2 bar, a booster pump is needed instead, or an accumulator combined with a charge pump such as the WaterBoost ACF1.
What size accumulator do I need?
Accumulators are typically sized on a 60 per cent usable rule – a 300 litre vessel delivers around 180 litres of boosted water per cycle. As a guide, a 2 to 3 bedroom home suits a 300 litre vessel such as the GWS GCB-300LV. Larger 4 to 5 bedroom homes or properties with multiple bathrooms typically need 450 to 600 litres. Vertical models save floor space, horizontal models suit lofts and roof spaces.