Grundfos Home Booster
Grundfos Home Booster Slave / Spare Tank 180l MCST0200
- Established 1975
- Trusted by thousands of customers
The Grundfos MCST0200 Slave Tank adds a second 180-litre usable store to a Grundfos Home Booster 3.0 or 4.5 bar set, taking total storage to 380 litres. Fit it where a home has 3–4 occupants, a slow-filling mains, or peak-time demand that empties the booster’s own tank.
It is the same 200-litre polypropylene tank as the Home Booster, complete with float valve and Type AB air gap, but without the pump, vessel or controller. It stands beside the booster on the same 1,000 × 600 × 600 mm footprint and links to it with a balance pipe, so both tanks fill from the mains and feed the one pump. 30 kg dry. Designed and built in the UK, WRAS-approved components.
More about this product
Product overview
The Grundfos MCST0200 Slave Tank is the add-on storage tank for the Grundfos Home Booster range. A Home Booster holds 180 litres of usable water; when a house has more occupants, a slow-filling mains, or morning and evening peaks that drain the tank faster than it refills, the slave tank doubles the store to 380 litres without changing the pump or controller.
It is built as the same 200-litre polypropylene tank as the booster, with its own float valve and Type AB air gap, but no pump, pressure vessel or controls. It stands alongside the booster on an identical 1,000 mm high × 600 × 600 mm footprint and is connected by a balance pipe at low level, so both tanks fill from the mains and the booster’s pump draws from the combined volume. A second overflow is piped to the same warning pipe. It suits both the 3.0 bar (MD/ME300200) and 4.5 bar (MD/ME450200) sets, and can be added to an existing installation. Designed and built in the UK.
Key features
When to add a slave tank
Technical specifications
| Model / SKU | Grundfos Home Booster Slave Tank MCST0200 |
| Suits | Grundfos Home Booster 3.0 bar (MD/ME300200) and 4.5 bar (MD/ME450200) |
| Tank capacity | 200 litres (180 litres usable), polypropylene |
| Total storage with booster | 380 litres usable |
| Mains connection | Float valve with Type AB air gap and overflow |
| Link to booster | Low-level balance pipe between tanks |
| Pump / controls | None; uses the booster’s pump and PM2 controller |
| Dimensions (H × W × D) | 1,000 × 600 × 600 mm (same as the Home Booster) |
| Weight | 30 kg dry, 52 kg boxed, 210 kg full |
| WRAS | WRAS-approved components |
| Installation | Beside the booster on a solid level base; not suitable for loft installation |
Frequently asked questions
Can I add it to a Home Booster that’s already installed?
Yes. It connects with a balance pipe to the booster tank and a tee into the mains feed, plus its own overflow. Allow another 600 × 600 mm of floor next to the booster.
Does it increase the pressure or flow?
No. Pressure and flow come from the booster’s pump, which is unchanged. The slave tank increases how long the booster can keep delivering before it runs low.
Does it need its own power supply?
No. There is nothing electrical in it.
How do I know if I need one?
If the booster runs dry or the PM2 trips at peak times, or the mains fills at under about 10 l/min, more storage is the answer. If the problem is weak pressure with the tank full, look at the 4.5 bar booster instead.
Can I fit more than one?
Grundfos rate the Home Booster with one slave tank. For storage beyond 380 litres, the DAB Esybox with Esytank or a WaterBoost tank-and-pump system is the better route.
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 Grundfos Home Booster Slave / Spare Tank 180l MCST0200. 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 a water booster pump?
A water booster pump increases the pressure of an existing water supply to give stronger flow at taps, showers and appliances. It can be a small inline pump fitted to the incoming mains, or a larger pump and tank set that draws from a break tank to feed the whole house. Boosters do not create water – they raise the pressure of the water already coming in.
What is the difference between an inline booster and a tank-and-pump booster?
An inline booster connects straight onto the incoming mains and is limited to 12 litres per minute under UK water regulations – examples include the Salamander HomeBoost and WaterBoost WB-Compact. A tank-and-pump booster, such as the Grundfos Home Booster or DAB Esybox with Esytank, draws from a break tank and can deliver much higher flow rates for larger homes with multiple bathrooms.
What is a variable speed booster pump?
A variable speed booster uses an inverter to adjust pump speed in real time to match demand. It maintains constant pressure as outlets open and close, runs more quietly than a fixed-speed pump and typically saves up to 50 per cent of the energy a fixed-speed equivalent would use. The DAB Esybox, DAB Esybox Mini 3 and Grundfos Scala2 are common variable speed examples.