Choosing an electric pump is not only about pressure or airflow. The pump nozzle must match the valve on your inflatable product.
For many inflatable kayaks with a drop-stitch floor, the drop-stitch floor uses a Halkey-Roberts (HR) valve, while the main boat chambers use Boston valves. One kayak can therefore require two different pump nozzles.
Two common inflatable valves: HR and Boston
This guide covers two common valve types. Do not buy an adapter only because it is described as “universal.” Match it to the actual valve on your product.
1. Halkey-Roberts (HR) Valve: Common on High-Pressure Floors and SUPs
A Halkey-Roberts valve, usually called an HR valve, is commonly used on SUPs, high-pressure inflatable boats and drop-stitch floors. It has a protective cap and a spring-loaded valve core underneath.
How to inflate an HR valve correctly
- Remove the protective cap.
- Make sure the centre valve pin is in the inflation position, not locked down in the deflation position.
- Insert the matching HR adapter and twist to lock it.
- Set the pump only to the PSI printed on the board, boat or floor.
- After inflation, remove the adapter carefully and replace the protective cap.
GR-633 nozzle guide for HR valves: Use the black HR locking connector with the white sealing ring, shown in the connection photo above. It must be inserted and twist-locked. Do not use the round Boston nozzle on an HR valve.
2. Boston Valve: Threaded Valves for Main Air Chambers and Everyday Inflatables
A Boston valve has a threaded body and screw cap. It is commonly used on the main air chambers of inflatable kayaks and rafts, as well as air tents, air mattresses, pools and other inflatable products.
GR-633 nozzle guide for Boston valves: Open the Boston valve cap, then use the round Boston nozzle. After inflation, close the cap securely.
HR valve vs Boston valve: which nozzle should you use?
| Valve type | Common application | Correct GR-633 nozzle | Important check |
|---|---|---|---|
| HR valve | SUP, high-pressure boat, drop-stitch floor | Black HR locking connector with white sealing ring | Insert and twist-lock; confirm the product’s maximum PSI |
| Boston valve | Main kayak/raft chambers, air tent, air mattress, pool and other inflatables | Round Boston nozzle | Open cap, make a secure seal, then close cap after inflation |
Do not force an HR adapter into a Boston valve, and do not use a Boston nozzle on an HR valve. An incorrect connection can leak air, inflate very slowly or damage the valve.
Common questions from inflatable kayak owners
My used inflatable kayak did not include the original pump adapter. What should I do?
Take clear photos of every valve with the cap closed and open. Check the model label and the maximum pressure shown for each chamber. On a kayak with a drop-stitch floor, you may need an HR adapter for the floor and a Boston nozzle for the main chambers.
The pump reaches its target pressure, but the boat still feels soft. Why?
First check the nozzle connection (our valve-seal troubleshooting guide walks through the full check). An HR adapter must be twist-locked, while a Boston nozzle must sit securely in the valve opening. If air leaks at the connection, the pump may sense pressure at the hose while the inflatable itself remains under-inflated. Use a small amount of soapy water around the valve connection to look for continuous bubbles. Keep water away from the pump, battery and charging port.
Can the GR-633 inflate every product with an HR valve?
No. Valve compatibility and pressure requirement are two different checks. The GR-633 can use the compatible HR connector, but its maximum pressure is 10 PSI. Use it only when the product label requires 10 PSI or less. A SUP or high-pressure drop-stitch floor requiring 12–15 PSI or more needs a dedicated high-pressure SUP pump.
Can I use one nozzle for every chamber on my kayak?
Usually not. A common kayak setup is an HR valve on the drop-stitch floor and Boston valves on the main air chambers. Check each chamber before inflating.
Quick checklist before inflating
- Check whether each chamber uses an HR valve or Boston valve.
- For a drop-stitch kayak floor, use the HR locking connector.
- For the main boat chambers, use the Boston nozzle.
- Read the maximum PSI printed on each chamber.
- For GR-633, do not exceed its 10 PSI maximum pressure.
- Test the pump, nozzle and valve connection at home before taking the kayak onto the water.
Need help matching a pump nozzle?
Send us a clear photo of the valve with its cap closed and open, the product model and the required PSI. We can help you identify the correct HR connector or Boston nozzle before you order.
