Mk7 Power Tubes & Spares
The Mk 7 unit has been made since the late 1980s. The present tube will fit all of the different types of Mk 7 – the Mk 7 Standard, Mk 7 Triple Spring, Mk 7 Hydraulicheck and Mk 7 Epoxy Powder Coated models.
The standard tube is filled with a wax that enables the window to be set to start opening between around 12°C (55°F) and 75°C (24°F). We also manufacture a tube that can be set to start opening the window at about 70°C. This is called a Mk 7 Orchid Wax tube and is available at a slight extra cost to the standard Mk 7 tube. Please contact us for details if you require this option.
Mk 7 tubes open the greenhouse window a maximum of 30cms (12 inches) and will lift a total vent weight of approx 12 kgs (a load of approx 6 kgs).
Mk 7 Power Tube
Alternative Shaped Plug on Mk 7
We use two types of plug on the end of the power tube and have illustrated them both. However, the type of plug does not affect the functioning of the tube and occurs because we manufacture the plugs on different machines. We illustrate them for information purposes only.
When you take the old tube out of the unit, you will have to damage the retainer washer that keeps the pin in place through the plug end of the tube. We always send out a new retainer washer with your new tube.
To illustrate the position of the washers and pin through the plug.
When you have inserted the new tube into the unit, follow the Mk 7 fitting instructions from Page 1, number 2… Place the Autovent in a cool place for half an hour…
When refitting your Mk 7 to the vent, make sure the straight links lie parallel to the glass in the vent i.e. the difference between the straight links and the glass in the window remains the same at both ends of the autovent even when the vent is close.
The Mk 7 unit, showing correct fitting to the vent
The photo shows the Mk 7 operating the vent when the window is semi-open. When the vent is completely shut, it is VERY IMPORTANT that the gap between the straight links and the glass in the vent is the SAME at BOTH ENDS.
This is very important because if the straight links do not lie parallel to the glass in the vent, part of the lifting force is wasted trying to push the vent against the hinge. This can result in severely overloading the unit and reducing its effectiveness and life. It also invalidates the guarantee.
All Mk 7 tubes are date stamped to show the month and year of manufacture.
Mk 7 Adjuster
Long Rivet, Short Rivet, Short Spacer, Long Spacer, Retainer Washer, Plastic Washer
Triple Spring Conversion Kit to enable a Mk 7 standard unit to be changed into a triple spring