FAQs
Frequently asked questions and their answers
Does a gate valve always have to be completely open or closed?
Yes, either open or closed! Gate valves are service elements, NOT regulating devices. If the valve is not fully open or closed, this can lead to cavitation.
Can Hawle valves be used for hot water?
No. Hawle products are designed for medium temperatures between 0°C and 40°C. They cannot be used at temperatures outside this range.
What is the difference between a valve with a manual drive and one with a motor drive?
Valves with a manual drive must be able to withstand at least 250 opening and closing operations according to the standard EN 1074. For valves with a motor drive, this figure is 2500 opening and closing operations.
Where should air release valves be used?
At every high point, on long stretches of pipeline on an incline or decline, after pumps and in every position at risk of negative pressure.
Does every air release valve need a chamber?
Up to a main line size of DN 250, Hawle combined air release valves can be used without a chamber.
What extension spindles can I use with a service valve?
For service valves, the correct extension spindle is 3/4” to 2” and has a thread for ease of assembly in a rigid or telescopic design.
Is the distance bush installed the wrong way round in the Hawle System 2000?
This is intentional. The distance bush deforms when the bolt is tightened, protecting the bare thread against corrosion.
When are support liners used in Hawle connections?
In the System 2000, a support liner must be used with thin-walled PE pipes (≥ SDR 21) and pressure pipelines.
A support liner is also required for Synoflex connections with PE pipes ≥ SDR 17.
Hawle offers two drilling machines for drilling under pressure. Why?
When drilling steel, ductile iron, fiber cement, PVC or PE pipes, we recommend drilling machine no. 5800. When drilling steel and ductile iron pipes with cement mortar cladding, we recommendation drilling machine no. 5805 with automatic feed.
What bolt circle criteria have to be observed from DN 200 upwards?
The correct bolt must be chosen depending on the working pressure. See the technical ‘Chapter R’ in the Hawle water catalog for more information.
Are Hawle hydrants frost-proof?
All Hawle hydrants have an independent drainage function and are therefore frost-proof. Drainage time: < 10 minutes. We recommend installing a ‘Sickerpipe’ drainage pipe for hydrants, which guarantees that the drainage function will always work correctly.
Can E2/E3 gate valves be retrofitted with an automatic actuator?
An automatic actuator can be fitted onto any E2 or E3 model. The actuator can be retrofitted up to the dimension 200, while larger dimensions can have the actuator installed in the production plant.
Do air release valves require maintenance?
Air release valves are not maintenance-free fittings and must therefore be serviced at regular intervals depending on the water quality.
What are the benefits of the corrosion protection ring?
All internal threads on Hawle products are fitted with a corrosion protection ring to prevent corrosion and incrustation. This significantly increases the service life of a threaded connection.