Graf Carat 3750 litre underground rainwater storage tank designed for installation below ground to serve commercial or residential premises.

Why buy this tank?

• Store rainwater ready for use under your garden
• Lifting kit not necessary - can be man-handled onto the site
• Exceptionally strong but light two piece Duralen moulding
• Time tested and backed by a 15 year manufacturer warranty
• Tank construction allows for manoeuvre into less accessible locations -even though doorways
• Components precision made for fast assembly
• Buy if you want to build your own system - pumps, filters pipes or buy a system ready made

The image at the top shows a Carat tank with a cutout to show the interior construction and an illustration of a tank with filters and an external pump available from rainwaterharvesting.co.uk in a typical garden setting. To see images showing the construction and scale of the tank visit here .

What do I get?

• Big, strong 2 piece tank for fitting underground
• Carat assembly kit including the seals
• Pedestrian load cover and tank sleeve (green) Product ID: GF-371010 Height 750-950 mm. Maximum tilt 5%. Child safety lock.
• Optional upgrade to a Maxi sleeve giving an extra 100mm of adjustment (the one in the middle)  Product ID: GF-371011
• Optional upgrade to a vehicle load cover (grey) Product ID: GF-371020
• Optional additional extension sleeve for even deeper sites Product ID: GF-371003 (the concertina thing in grey)

About the Tank and Graf

The Graf Carat tank is the largest tank of its kind in the world to be manufactured by injection compression moulding. This technique provides the tank with unbeatable stability and ensures that each component is produced with the highest accuracy. Graf have invested €20m in their factory near Freiburg for the Carat range, introduced in early 2007.

Like the Graf Hercules, the Carat comes in two halves so you can carry it through tight spaces even dorways.. (and so we can stack many of them on one pallet for bulk transport). A centering bolt on the tank flange makes assembly accurate and patented seal laboratory tested for 25 years the quick knock on connections  ensure there are no leaks between the two sections... and yet you can disassemble it if you like. The material used is a PE variant called Duralen.

Features Check:

• Preferably for underground mounting  (can be used above ground at owner's option)
• German manufactured, TÜV safety-tested
• Patented quick connection (no screws required for mounting)
• Permanently watertight: durably sealed thanks to solid profile sealing
• Easy transport thanks to low weight and practicable size
• Durably sealed thanks to solid profile sealing
• See table for dimensions and weight

Connections for underground installation:

Holes are pre-cut in the turret or dome for connecting the filter inside the turret. We recommend use of British standard 110mm brown piping (more accurately 4.25 inches or 108mm external diameter) as supplied by builders merchants like Jewson, Wickes etc. If you are using 110mm piping between your roof's downpipes and the tank, and between the tank and the drain or soakaway, then you have no worries about compatibility of pipe sizes.

Compare the Carat S Tank sizes
Tank	2700 Litres	3750 Litres	4800 Litres	6500 Litres
Product Code	370001	370002	370003	370004
Weight	120 kg	150 kg	185 kg	220 kg
Length	2080mm	2280mm	2280mm	2390mm
Width	1565mm	1755mm	1985mm	2190mm
Height	1400mm	1590mm	1820mm	2100mm
Total Height	2010mm	2200mm	2430mm	2710mm
Half Height ie before assembly (for access)	700mm	790mm	910mm	1050mm
Go to other tank sizes	Go to a 2700L tank	You are here	Go to a 4800L tank	Go to a 6500L tank

* The half height is a useful dimension if your site is at the back of a house and you have to get the tank through the doors of the house. The Carat is shipped in two halves with the turret separate. By tipping the half tank on its side you and a colleague can walk it through a narrow door. Your door width needs to be marginally wider than the half height shown.

Optional Upgrades.

1) Bit more leeway on the tank depth: Opt for a Maxi sleeve giving an extra 100mm of adjustment (see above)  Product ID: GF-371011

2) Support car traffic: (but not trucks and HGVs) when fitted with the optional dome and cast iron lid. Contractors often ask us the dimensions of the turret. The Vehicle loading lid can be found here Product ID: GF-371020

• Height variable between 750-1050 mm.
• Maximum tilt 5%.
• Cast iron cover.
• Child safety lock.
• Dark Grey.

3) Deeper holes: You can compensate for a deep hole with a tank turret sleeve extension Product ID: GF-371003 which extends the height of the pedestrian dome shaft PE lid by 1000-1500mm

More research:

• Download a technical drawing of the Carat 3750 litre tank by clicking here
• Detailed catalogue on the Carat tank range can be downloaded by clicking here.
• Otto Graf in Germany have a wealth of technical data and application illustrations on their website, including downloads and videos. To visit the Graf website please click here